a little code clean-up

defined a few atomic operation macros

bin/hak.c

@@ -249,8 +249,8 @@ static int handle_logopt (hak_t* hak, const hak_bch_t* logstr)
 	}
 
 	fname.ptr = (hak_bch_t*)logstr;
-	hak_setoption (hak, HAK_LOG_TARGET_BCS, &fname);
+	hak_setoption (hak, HAK_OPT_LOG_TARGET_BCS, &fname);
-	hak_setoption (hak, HAK_LOG_MASK, &logmask);
+	hak_setoption (hak, HAK_OPT_LOG_MASK, &logmask);
 	return 0;
 }
 
@@ -280,9 +280,9 @@ static int handle_dbgopt (hak_t* hak, const hak_bch_t* str)
 	}
 	while (cm);
 
-	hak_getoption(hak, HAK_TRAIT, &trait);
+	hak_getoption(hak, HAK_OPT_TRAIT, &trait);
 	trait |= dbgopt;
-	hak_setoption(hak, HAK_TRAIT, &trait);
+	hak_setoption(hak, HAK_OPT_TRAIT, &trait);
 	return 0;
 }
 #endif
@@ -865,6 +865,7 @@ int main (int argc, char* argv[])
 		{ ":debug",       '\0' },
 #endif
 		{ ":heapsize",    '\0' },
+		{ ":incdirs",     'I' },
 		{ ":log",         'l'  },
 		{ "info",         '\0' },
 		{ ":modlibdirs",  '\0' },
@@ -873,7 +874,7 @@ int main (int argc, char* argv[])
 	};
 	static hak_bopt_t opt =
 	{
-		"l:v",
+		"I:l:v",
 		lopt
 	};
 
@@ -882,6 +883,7 @@ int main (int argc, char* argv[])
 	int verbose = 0;
 	int show_info = 0;
 	const char* modlibdirs = HAK_NULL;
+	const char* incdirs = HAK_NULL;
 
 #if defined(HAK_BUILD_DEBUG)
 	const char* dbgopt = HAK_NULL;
@@ -896,6 +898,7 @@ int main (int argc, char* argv[])
 		fprintf(stderr, "Usage: %s [options] script-filename [output-filename]\n", argv[0]);
 		fprintf(stderr, "Options are:\n");
 		fprintf(stderr, " --info                show build information\n");
+		fprintf(stderr, " -I, --incdirs string  specify the list of include directories\n");
 		fprintf(stderr, " -l, --log     string  specify the log file path and options\n");
 		fprintf(stderr, " --modlibdirs  string  specify directories to load modules from\n");
 		fprintf(stderr, " -v                    show verbose messages\n");
@@ -907,6 +910,10 @@ int main (int argc, char* argv[])
 	{
 		switch (c)
 		{
+			case 'I':
+				incdirs = opt.arg;
+				break;
+
 			case 'l':
 				logopt = opt.arg;
 				break;
@@ -979,12 +986,16 @@ int main (int argc, char* argv[])
 
 	{
 		hak_oow_t tab_size;
-		tab_size = 5000;
+		tab_size = HAK_DFL_SYMTAB_SIZE;
-		hak_setoption (hak, HAK_SYMTAB_SIZE, &tab_size);
+		hak_setoption (hak, HAK_OPT_SYMTAB_SIZE, &tab_size);
-		tab_size = 5000;
+		tab_size = HAK_DFL_SYSDIC_SIZE;
-		hak_setoption (hak, HAK_SYSDIC_SIZE, &tab_size);
+		hak_setoption (hak, HAK_OPT_SYSDIC_SIZE, &tab_size);
-		tab_size = 600; /* TODO: choose a better stack size or make this user specifiable */
+		tab_size = HAK_DFL_PROCSTK_SIZE; /* TODO: choose a better stack size or make this user specifiable */
-		hak_setoption (hak, HAK_PROCSTK_SIZE, &tab_size);
+		hak_setoption (hak, HAK_OPT_PROCSTK_SIZE, &tab_size);
+		tab_size = HAK_DFL_EXSTK_SIZE; /* TODO: choose a better stack size or make this user specifiable */
+		hak_setoption (hak, HAK_OPT_EXSTK_SIZE, &tab_size);
+		tab_size = HAK_DFL_CLSTK_SIZE; /* TODO: choose a better stack size or make this user specifiable */
+		hak_setoption (hak, HAK_OPT_CLSTK_SIZE, &tab_size);
 	}
 
 	{
@@ -993,34 +1004,29 @@ int main (int argc, char* argv[])
 		/*trait |= HAK_TRAIT_NOGC;*/
 		trait |= HAK_TRAIT_AWAIT_PROCS;
 		trait |= HAK_TRAIT_LANG_ENABLE_EOL;
-		hak_setoption (hak, HAK_TRAIT, &trait);
+		hak_setoption (hak, HAK_OPT_TRAIT, &trait);
+	}
+
+	if (incdirs)
+	{
+		/* the option is stored in both encodings, so the byte form from
+		 * the command line goes in as is - no conversion needed here. */
+		if (hak_setoption(hak, HAK_OPT_INCDIRS_BCSTR, incdirs) <= -1)
+		{
+			hak_logbfmt(hak, HAK_LOG_STDERR,"ERROR: cannot set incdirs - [%d] %js\n", hak_geterrnum(hak), hak_geterrmsg(hak));
+			goto oops;
+		}
 	}
 
 	if (modlibdirs)
 	{
-	#if defined(HAK_OOCH_IS_UCH)
+		/* the option is stored in both encodings, so the byte form from
-		hak_ooch_t* tmp;
+		 * the command line goes in as is - no conversion needed here. */
-		tmp = hak_dupbtoucstr(hak, modlibdirs, HAK_NULL);
+		if (hak_setoption(hak, HAK_OPT_MODLIBDIRS_BCSTR, modlibdirs) <= -1)
-		if (HAK_UNLIKELY(!tmp))
-		{
-			hak_logbfmt(hak, HAK_LOG_STDERR,"ERROR: cannot duplicate modlibdirs - [%d] %js\n", hak_geterrnum(hak), hak_geterrmsg(hak));
-			goto oops;
-		}
-
-		if (hak_setoption(hak, HAK_MOD_LIBDIRS, tmp) <= -1)
-		{
-			hak_logbfmt(hak, HAK_LOG_STDERR,"ERROR: cannot set modlibdirs - [%d] %js\n", hak_geterrnum(hak), hak_geterrmsg(hak));
-			hak_freemem(hak, tmp);
-			goto oops;
-		}
-		hak_freemem(hak, tmp);
-	#else
-		if (hak_setoption(hak, HAK_MOD_LIBDIRS, modlibdirs) <= -1)
 		{
 			hak_logbfmt(hak, HAK_LOG_STDERR,"ERROR: cannot set modlibdirs - [%d] %js\n", hak_geterrnum(hak), hak_geterrmsg(hak));
 			goto oops;
 		}
-	#endif
 	}
 
 	memset (&hakcb, 0, HAK_SIZEOF(hakcb));
@@ -1091,9 +1097,9 @@ int main (int argc, char* argv[])
 // in the non-INTERACTIVE mode, the compiler generates MAKE_BLOCK for lambda functions.
 {
 	hak_bitmask_t trait;
-	hak_getoption(hak, HAK_TRAIT, &trait);
+	hak_getoption(hak, HAK_OPT_TRAIT, &trait);
 	trait |= HAK_TRAIT_INTERACTIVE;
-	hak_setoption(hak, HAK_TRAIT, &trait);
+	hak_setoption(hak, HAK_OPT_TRAIT, &trait);
 }
 #endif
 

bin/main.go

@@ -4,8 +4,10 @@ import (
 	"flag"
 	"fmt"
 	"hak"
+	"io"
 	"os"
-	//"strings"
+	"strings"
+	"time"
 )
 
 /*
@@ -18,6 +20,9 @@ import (
 `))
 */
 
+/* 0 means no pre-allocated heap, as in bin/hak.c */
+const DEFAULT_HEAPSIZE uint = 0
+
 /* to be set in build time */
 var BINDIR = "."
 var SBINDIR = "."
@@ -25,10 +30,14 @@ var LIBDIR = "."
 var SYSCONFDIR = "."
 
 type Param struct {
-	log_file   string
+	log_target string
+	log_mask   hak.BitMask
 	input_file string
 	heapsize   uint
 	modlibdirs string
+	incdirs    string
+	verbose    bool
+	show_info  bool
 	fs_usage   func()
 }
 
@@ -36,6 +45,93 @@ func empty_usage() {
 
 }
 
+/* the filter names accepted after the comma in --log, mirroring the xtab
+ * table in handle_logopt() of bin/hak.c. 'and' marks the entries that clear
+ * bits instead of setting them. */
+type log_filter struct {
+	name string
+	and  bool
+	mask hak.BitMask
+}
+
+var log_filters = []log_filter{
+	{"", false, 0},
+
+	{"app", false, hak.LOG_APP},
+	{"compiler", false, hak.LOG_COMPILER},
+	{"vm", false, hak.LOG_VM},
+	{"mnemonic", false, hak.LOG_MNEMONIC},
+	{"gc", false, hak.LOG_GC},
+	{"ic", false, hak.LOG_IC},
+	{"primitive", false, hak.LOG_PRIMITIVE},
+
+	/* a specific level */
+	{"fatal", false, hak.LOG_FATAL},
+	{"error", false, hak.LOG_ERROR},
+	{"warn", false, hak.LOG_WARN},
+	{"info", false, hak.LOG_INFO},
+	{"debug", false, hak.LOG_DEBUG},
+
+	/* a specific level or higher */
+	{"fatal+", false, hak.LOG_FATAL},
+	{"error+", false, hak.LOG_FATAL | hak.LOG_ERROR},
+	{"warn+", false, hak.LOG_FATAL | hak.LOG_ERROR | hak.LOG_WARN},
+	{"info+", false, hak.LOG_FATAL | hak.LOG_ERROR | hak.LOG_WARN | hak.LOG_INFO},
+	{"debug+", false, hak.LOG_FATAL | hak.LOG_ERROR | hak.LOG_WARN | hak.LOG_INFO | hak.LOG_DEBUG},
+
+	/* a specific level or lower */
+	{"fatal-", false, hak.LOG_FATAL | hak.LOG_ERROR | hak.LOG_WARN | hak.LOG_INFO | hak.LOG_DEBUG},
+	{"error-", false, hak.LOG_ERROR | hak.LOG_WARN | hak.LOG_INFO | hak.LOG_DEBUG},
+	{"warn-", false, hak.LOG_WARN | hak.LOG_INFO | hak.LOG_DEBUG},
+	{"info-", false, hak.LOG_INFO | hak.LOG_DEBUG},
+	{"debug-", false, hak.LOG_DEBUG},
+
+	/* exclude a specific level */
+	{"-fatal", true, ^hak.LOG_FATAL},
+	{"-error", true, ^hak.LOG_ERROR},
+	{"-warn", true, ^hak.LOG_WARN},
+	{"-info", true, ^hak.LOG_INFO},
+	{"-debug", true, ^hak.LOG_DEBUG},
+}
+
+/* split "path,filter,filter" into a target and a log mask. with no comma the
+ * whole string is the target and every level and type is enabled. */
+func parse_logopt(logstr string) (string, hak.BitMask, error) {
+	var comma int = strings.Index(logstr, ",")
+	var mask hak.BitMask
+
+	if comma < 0 {
+		return logstr, hak.LOG_ALL_LEVELS | hak.LOG_ALL_TYPES, nil
+	}
+
+	for _, f := range strings.Split(logstr[comma+1:], ",") {
+		var i int
+		for i = 0; i < len(log_filters); i++ {
+			if log_filters[i].name == f {
+				if log_filters[i].and {
+					mask &= log_filters[i].mask
+				} else {
+					mask |= log_filters[i].mask
+				}
+				break
+			}
+		}
+		if i >= len(log_filters) {
+			return "", 0, fmt.Errorf("unrecognized log filter - %s - in %s", f, logstr)
+		}
+	}
+
+	/* nothing selected in a category means everything in that category */
+	if (mask & hak.LOG_ALL_TYPES) == 0 {
+		mask |= hak.LOG_ALL_TYPES
+	}
+	if (mask & hak.LOG_ALL_LEVELS) == 0 {
+		mask |= hak.LOG_ALL_LEVELS
+	}
+
+	return logstr[0:comma], mask, nil
+}
+
 func handle_arguments(param *Param) error {
 	/*
 	var nargs int = len(os.Args)
@@ -64,34 +160,110 @@ func handle_arguments(param *Param) error {
 	var fs *flag.FlagSet
 	var heapsize *uint
 	var modlibdirs *string
+	var incdirs *string
 	var log *string
+	var verbose *bool
+	var show_info *bool
 	var err error
 
 	fs = flag.NewFlagSet(os.Args[0], flag.ContinueOnError)
 
-	heapsize = fs.Uint("heapsize", 0, "specify heap size")
+	/* the same set bin/hak.c accepts. the flag package treats -x and --x
-	modlibdirs = fs.String("modlibdirs", "", "specify module library directories")
+	 * alike, so registering both spellings of a short option is enough to
-	log = fs.String("log", "", "specify log file")
+	 * give -I and --incdirs the same destination. */
+	heapsize = fs.Uint("heapsize", DEFAULT_HEAPSIZE, "specify the heap size in bytes")
+	incdirs = fs.String("incdirs", "", "specify the list of include directories")
+	fs.StringVar(incdirs, "I", "", "specify the list of include directories")
+	log = fs.String("log", "", "specify the log file path and options")
+	fs.StringVar(log, "l", "", "specify the log file path and options")
+	modlibdirs = fs.String("modlibdirs", "", "specify directories to load modules from")
+	verbose = fs.Bool("v", false, "show verbose messages")
+	show_info = fs.Bool("info", false, "show build information")
 
 	param.fs_usage = fs.Usage
 	fs.Usage = empty_usage  // i don't want fs.Parse() print the usage
+	fs.SetOutput(io.Discard) // nor its own copy of the error, which we report ourselves
 	err = fs.Parse(os.Args[1:])
 	fs.Usage = param.fs_usage // restore it
+	fs.SetOutput(os.Stderr)   // so the restored usage still prints
 	if err != nil {
 		return fmt.Errorf("command line error - %s", err.Error())
 	}
 
+	param.heapsize = *heapsize
+	param.incdirs = *incdirs
+	param.modlibdirs = *modlibdirs
+	param.verbose = *verbose
+	param.show_info = *show_info
+
+	if *log != "" {
+		param.log_target, param.log_mask, err = parse_logopt(*log)
+		if err != nil {
+			return err
+		}
+	}
+
+	/* --info answers on its own and needs no script */
+	if param.show_info {
+		return nil
+	}
+
 	if fs.NArg() < 1 {
 		return fmt.Errorf("no input file specified")
 	} else if fs.NArg() > 1 {
+		/* bin/hak.c also takes an optional output file as the second
+		 * argument, but the go binding attaches the user data streams
+		 * through handler objects rather than a path, so there is nothing
+		 * to pass it to yet. */
 		return fmt.Errorf("too many input files specified")
 	}
 
-	param.input_file = fs.Arg(0);
+	param.input_file = fs.Arg(0)
-	param.log_file = *log // TODO: parse the option part  (e.g. --log /dev/stderr,debug+)
+	return nil
-	param.heapsize = *heapsize // TODO: set this to hak
+}
-	param.modlibdirs = *modlibdirs // TODO: set this to hak
+
-	return nil;
+func start_ticker(x *hak.Hak) func() {
+	var ticker *time.Ticker
+	var ticker_stop chan bool
+	var ticker_done chan bool
+	var stopper func()
+
+	ticker = time.NewTicker(20 * time.Millisecond)
+	ticker_done = make(chan bool)
+	ticker_stop = make(chan bool)
+
+	go func() {
+		for {
+			select {
+				case <- ticker_stop:
+					goto done
+				case <- ticker.C:
+					x.RaiseTick()
+			}
+		}
+
+	done:
+		ticker.Stop()
+		ticker_done <- true
+	}()
+	x.RcvTick(true)
+
+	stopper = func() {
+		x.RcvTick(false)
+		ticker_stop <- true
+		<- ticker_done // wait for the ticker to stop
+
+		// if i don't close the the two channels below, the multiple calls to the
+		// returned stopper function wouldn't cause immediate panic for writing
+		// on a closed channel. but i would still close them as i don't want to
+		// cater for generic use of this function and this function wasn't
+		// written to be generic. i don't care to use any other more advanced
+		// mechanisms. the caller must ensure to call this stopper only once.
+		close(ticker_stop)
+		close(ticker_done)
+	}
+
+	return stopper
 }
 
 func main() {
@@ -99,6 +271,7 @@ func main() {
 	var x *hak.Hak = nil
 	var err error = nil
 	var param Param
+	var stop_ticker func()
 
 	var rfh hak.CciFileHandler
 	var sfh hak.UdiFileHandler
@@ -111,20 +284,39 @@ func main() {
 		os.Exit(1)
 	}
 
+	if param.show_info {
+		fmt.Println(hak.BuildInfo())
+		os.Exit(0)
+	}
+
 	x, err = hak.New()
 	if err != nil {
 		fmt.Printf("ERROR: failed to instantiate hak - %s\n", err.Error())
 		os.Exit(1)
 	}
 
-	if param.log_file != "" {
+	if param.log_target != "" {
-		x.SetLogMask(^hak.BitMask(0))
+		/* honour both halves of --log. the previous code discarded the path
-		x.SetLogTarget("/dev/stderr")
+		 * and always logged everything to /dev/stderr. */
+		x.SetLogMask(param.log_mask)
+		err = x.SetLogTarget(param.log_target)
+		if err != nil {
+			fmt.Printf("ERROR: failed to set log target - %s\n", err.Error())
+			os.Exit(1)
+		}
+	}
+
+	if param.incdirs != "" {
+		x.SetIncDirs(param.incdirs)
+	}
+
+	if param.modlibdirs != "" {
+		x.SetModLibDirs(param.modlibdirs)
 	}
 
 	x.SetTrait(x.GetTrait() | hak.TRAIT_LANG_ENABLE_EOL)
 
-	err = x.Ignite(1000000)
+	err = x.Ignite(uintptr(param.heapsize))
 	if err != nil {
 		fmt.Printf("ERROR: failed to ignite - %s\n", err.Error())
 		goto oops
@@ -169,16 +361,25 @@ func main() {
 		goto oops
 	}
 
+	/* Decode() writes the bytecode mnemonics through the log, so it only
+	 * produces anything when --log selects the mnemonic type. the log mask
+	 * is no longer cleared afterwards - doing that silenced --log for the
+	 * whole of Execute(). */
 	x.Decode()
-	x.SetLogMask(0)
 
+	stop_ticker = start_ticker(x)
 	err = x.Execute()
+	stop_ticker()
 	if err != nil {
 		//fmt.Printf("ERROR: %s[%d:%d] - %s\n", herr.File, herr.Line, herr.Colm, herr.Msg)
 		fmt.Printf("ERROR: %s\n", err.Error())
 		goto oops
 	}
 
+	if param.verbose {
+		fmt.Printf("EXECUTION OK - %s\n", param.input_file)
+	}
+
 	x.Close()
 	os.Exit(0)
 

configure

@@ -16590,6 +16590,45 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 
 
 
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether compiler supports \u escape sequences" >&5
+printf %s "checking whether compiler supports \u escape sequences... " >&6; }
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+		/* define a macro that forces a compilation error if condition is false */
+		#define STATIC_ASSERT(expr) char assert_array[(expr) ? 1 : -1]
+
+int
+main (void)
+{
+
+		/* true UTF-8 "\u00e9" is 3 bytes including the null terminator.
+		* GCC 2.95's "u00e9" is 6 bytes. */
+		STATIC_ASSERT(sizeof("\u00e9") == 3);
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+
+		{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+
+printf "%s\n" "#define HAVE_ESCAPE_U 1" >>confdefs.h
+
+
+else case e in #(
+  e)
+		{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+
+ ;;
+esac
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for __builtin_memset" >&5
 printf %s "checking for __builtin_memset... " >&6; }
 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -17157,6 +17196,7 @@ then :
 
 fi
 
+
 ac_fn_c_check_func "$LINENO" "posix_spawn" "ac_cv_func_posix_spawn"
 if test "x$ac_cv_func_posix_spawn" = xyes
 then :

configure.ac

@@ -70,6 +70,24 @@ AC_SUBST(LIBM, $LIBM)
 
 AX_PTHREAD()
 
+dnl check some compiler features
+AC_MSG_CHECKING([whether compiler supports \u escape sequences])
+AC_COMPILE_IFELSE(
+	[AC_LANG_PROGRAM([
+		/* define a macro that forces a compilation error if condition is false */
+		#define STATIC_ASSERT(expr) char assert_array[(expr) ? 1 : -1]
+	], [
+		/* true UTF-8 "\u00e9" is 3 bytes including the null terminator.
+		* GCC 2.95's "u00e9" is 6 bytes. */
+		STATIC_ASSERT(sizeof("\u00e9") == 3);
+	])], [
+		AC_MSG_RESULT([yes])
+		AC_DEFINE([HAVE_ESCAPE_U], [1], [Define to 1 if \u encodes properly])
+	], [
+		AC_MSG_RESULT([no])
+	]
+)
+
 dnl check some compiler builtins
 AC_MSG_CHECKING([for __builtin_memset])
 AC_LINK_IFELSE(
@@ -132,6 +150,7 @@ AC_CHECK_FUNCS([sigaction signal])
 AC_CHECK_FUNCS([snprintf _vsnprintf _vsnwprintf strerror_r])
 AC_CHECK_FUNCS([accept4 pipe2 epoll_create epoll_create1 kqueue kqueue1])
 AC_CHECK_FUNCS([isatty mmap munmap])
+
 AC_CHECK_FUNCS([posix_spawn getrlimit sysconf dirfd])
 dnl dirfd may be provided as a macro rather than a function
 AC_CHECK_DECLS([dirfd],[],[],[[#include <dirent.h>]])

hak-cb.go

@@ -12,6 +12,7 @@ import (
 	"io"
 	"os"
 	"path"
+	"strings"
 	"path/filepath"
 	"reflect"
 	"sync"
@@ -96,6 +97,8 @@ func hak_go_cci_handler(c *C.hak_t, cmd C.hak_io_cmd_t, arg unsafe.Pointer) C.in
 		var (
 			ioarg         *C.hak_io_cciarg_t
 			name          string
+			raw           string
+			try_incdirs   bool
 			fd            int
 			tptr          unsafe.Pointer
 			tlen          C.size_t
@@ -110,33 +113,64 @@ func hak_go_cci_handler(c *C.hak_t, cmd C.hak_io_cmd_t, arg unsafe.Pointer) C.in
 			// actual included stream
 			var includer_name string
 
-			name = string(ucstr_to_rune_slice(ioarg.name))
+			raw = string(ucstr_to_rune_slice(ioarg.name))
 
 			tptr = ioarg.includer.handle
 			tlen = *(*C.size_t)(unsafe.Pointer(uintptr(tptr) + unsafe.Sizeof(fd)))
 
 			includer_name = C.GoStringN((*C.char)(unsafe.Pointer(uintptr(tptr)+unsafe.Sizeof(fd)+unsafe.Sizeof(tlen))), C.int(tlen))
-			name = filepath.Join(path.Dir(includer_name), name)
+			name = filepath.Join(path.Dir(includer_name), raw)
+
+			// a name anchored by the author - absolute, or explicitly ./ or
+			// ../ - is meant to resolve against the includer alone. anything
+			// else may fall back to the include directories. this mirrors
+			// what open_cci_stream() does in lib/std.c.
+			try_incdirs = !filepath.IsAbs(raw) &&
+				!strings.HasPrefix(raw, "./") && !strings.HasPrefix(raw, "../")
+		}
+
+		// [NOTE] the open has to happen before the allocation below, because
+		//        the include-directory search can settle on a different (and
+		//        longer) path than the one first tried, and the block is
+		//        sized from the name it ends up storing.
+		if ioarg.includer == nil {
+			fd = -1
+		} else {
+			fd, err = g.io.cci.Open(g, name)
+			if err != nil && try_incdirs {
+				// walk the colon-separated include directories, as the C
+				// reader does. an empty entry means the current directory.
+				for _, dir := range strings.Split(g.GetIncDirs(), ":") {
+					var cand string = filepath.Join(dir, raw)
+					var fd2 int
+					var err2 error
+
+					fd2, err2 = g.io.cci.Open(g, cand)
+					if err2 == nil {
+						// the stored name becomes the includer path for
+						// anything this file includes in turn, so it has to
+						// be the path that actually opened
+						fd, err, name = fd2, nil, cand
+						break
+					}
+				}
+			}
+			if err != nil {
+				g.set_errmsg(C.HAK_EIOERR, err.Error())
+				return -1
+			}
 		}
 
 		tlen = C.size_t(len(name)) // number of bytes in the string
 		tptr = C.hak_allocmem(c, C.size_t(unsafe.Sizeof(fd)) + C.size_t(unsafe.Sizeof(tlen)) + tlen)
 		if tptr == nil {
+			if ioarg.includer != nil {
+				g.io.cci.Close(fd)
+			}
 			g.set_errmsg(C.HAK_ESYSMEM, "cci name allocation failure")
 			return -1
 		}
 
-		if ioarg.includer == nil {
-			fd = -1
-		} else {
-			fd, err = g.io.cci.Open(g, name)
-			if err != nil {
-				g.set_errmsg(C.HAK_EIOERR, err.Error())
-				C.hak_freemem(c, tptr)
-				return -1
-			}
-		}
-
 		// | fd | length | name bytes of the length |
 		*(*int)(tptr) = fd;
 		*(*C.size_t)(unsafe.Pointer(uintptr(tptr)+unsafe.Sizeof(fd))) = tlen;

hak.go

@@ -76,6 +76,38 @@ type BitMask C.hak_bitmask_t
 
 const TRAIT_LANG_ENABLE_EOL BitMask = C.HAK_TRAIT_LANG_ENABLE_EOL
 
+/* log levels */
+const (
+	LOG_DEBUG BitMask = C.HAK_LOG_DEBUG
+	LOG_INFO  BitMask = C.HAK_LOG_INFO
+	LOG_WARN  BitMask = C.HAK_LOG_WARN
+	LOG_ERROR BitMask = C.HAK_LOG_ERROR
+	LOG_FATAL BitMask = C.HAK_LOG_FATAL
+)
+
+/* log types */
+const (
+	LOG_UNTYPED   BitMask = C.HAK_LOG_UNTYPED
+	LOG_COMPILER  BitMask = C.HAK_LOG_COMPILER
+	LOG_VM        BitMask = C.HAK_LOG_VM
+	LOG_MNEMONIC  BitMask = C.HAK_LOG_MNEMONIC
+	LOG_GC        BitMask = C.HAK_LOG_GC
+	LOG_IC        BitMask = C.HAK_LOG_IC
+	LOG_PRIMITIVE BitMask = C.HAK_LOG_PRIMITIVE
+	LOG_APP       BitMask = C.HAK_LOG_APP
+)
+
+const (
+	LOG_ALL_LEVELS BitMask = C.HAK_LOG_ALL_LEVELS
+	LOG_ALL_TYPES  BitMask = C.HAK_LOG_ALL_TYPES
+)
+
+/* BuildInfo answers how the underlying C library was configured. it mirrors
+ * what bin/hak.c prints for --info. */
+func BuildInfo() string {
+	return fmt.Sprintf("Configured with: %s %s", C.HAK_CONFIGURE_CMD, C.HAK_CONFIGURE_ARGS)
+}
+
 func deregister_instance(g *Hak) {
 	if g.inst_no >= 0 {
 		inst_table.delete_instance(g.inst_no)
@@ -142,7 +174,7 @@ func (hak *Hak) GetTrait() BitMask {
 	var x C.int
 	var log_mask BitMask = 0
 
-	x = C.hak_getoption(hak.c, C.HAK_TRAIT, unsafe.Pointer(&log_mask))
+	x = C.hak_getoption(hak.c, C.HAK_OPT_TRAIT, unsafe.Pointer(&log_mask))
 	if x <= -1 {
 		// this must not happen
 		panic(fmt.Errorf("unable to get log mask - %s", hak.get_errmsg()))
@@ -154,7 +186,7 @@ func (hak *Hak) GetTrait() BitMask {
 func (hak *Hak) SetTrait(log_mask BitMask) {
 	var x C.int
 
-	x = C.hak_setoption(hak.c, C.HAK_TRAIT, unsafe.Pointer(&log_mask))
+	x = C.hak_setoption(hak.c, C.HAK_OPT_TRAIT, unsafe.Pointer(&log_mask))
 	if x <= -1 {
 		// this must not happen
 		panic(fmt.Errorf("unable to set log mask - %s", hak.get_errmsg()))
@@ -165,7 +197,7 @@ func (hak *Hak) GetLogMask() BitMask {
 	var x C.int
 	var log_mask BitMask = 0
 
-	x = C.hak_getoption(hak.c, C.HAK_LOG_MASK, unsafe.Pointer(&log_mask))
+	x = C.hak_getoption(hak.c, C.HAK_OPT_LOG_MASK, unsafe.Pointer(&log_mask))
 	if x <= -1 {
 		// this must not happen
 		panic(fmt.Errorf("unable to get log mask - %s", hak.get_errmsg()))
@@ -177,7 +209,7 @@ func (hak *Hak) GetLogMask() BitMask {
 func (hak *Hak) SetLogMask(log_mask BitMask) {
 	var x C.int
 
-	x = C.hak_setoption(hak.c, C.HAK_LOG_MASK, unsafe.Pointer(&log_mask))
+	x = C.hak_setoption(hak.c, C.HAK_OPT_LOG_MASK, unsafe.Pointer(&log_mask))
 	if x <= -1 {
 		// this must not happen
 		panic(fmt.Errorf("unable to set log mask - %s", hak.get_errmsg()))
@@ -188,27 +220,78 @@ func (hak *Hak) GetLogTarget() string {
 	var x C.int
 	var tgt *C.char
 
-	x = C.hak_getoption(hak.c, C.HAK_LOG_TARGET_BCSTR, unsafe.Pointer(&tgt))
+	x = C.hak_getoption(hak.c, C.HAK_OPT_LOG_TARGET_BCSTR, unsafe.Pointer(&tgt))
 	if x <= -1 {
 		// this must not happen
-		panic(fmt.Errorf("unable to set log target - %s", hak.get_errmsg()))
+		panic(fmt.Errorf("unable to get log target - %s", hak.get_errmsg()))
 	}
 
 	return C.GoString(tgt)
 }
 
-func (hak *Hak) SetLogTarget(target string) {
+func (hak *Hak) SetLogTarget(target string) error {
 	var x C.int
 	var tgt *C.char
 
 	tgt = C.CString(target) // TODO: need error check?
 	defer C.free(unsafe.Pointer(tgt))
 
-	x = C.hak_setoption(hak.c, C.HAK_LOG_TARGET_BCSTR, unsafe.Pointer(tgt))
+	x = C.hak_setoption(hak.c, C.HAK_OPT_LOG_TARGET_BCSTR, unsafe.Pointer(tgt))
+	if x <= -1 { return hak.make_errinfo() }
+
+	return nil
+}
+
+func (hak *Hak) GetIncDirs() string {
+	var x C.int
+	var tgt *C.char
+
+	x = C.hak_getoption(hak.c, C.HAK_OPT_INCDIRS_BCSTR, unsafe.Pointer(&tgt))
 	if x <= -1 {
 		// this must not happen
-		panic(fmt.Errorf("unable to set log target - %s", hak.get_errmsg()))
+		panic(fmt.Errorf("unable to get include directories - %s", hak.get_errmsg()))
 	}
+
+	return C.GoString(tgt)
+}
+
+func (hak *Hak) SetIncDirs(target string) error {
+	var x C.int
+	var tgt *C.char
+
+	tgt = C.CString(target) // TODO: need error check?
+	defer C.free(unsafe.Pointer(tgt))
+
+	x = C.hak_setoption(hak.c, C.HAK_OPT_INCDIRS_BCSTR, unsafe.Pointer(tgt))
+	if x <= -1 { return hak.make_errinfo() }
+
+	return nil
+}
+
+func (hak *Hak) GetModLibDirs() string {
+	var x C.int
+	var tgt *C.char
+
+	x = C.hak_getoption(hak.c, C.HAK_OPT_MODLIBDIRS_BCSTR, unsafe.Pointer(&tgt))
+	if x <= -1 {
+		// this must not happen
+		panic(fmt.Errorf("unable to get module library directories - %s", hak.get_errmsg()))
+	}
+
+	return C.GoString(tgt)
+}
+
+func (hak *Hak) SetModLibDirs(target string) error {
+	var x C.int
+	var tgt *C.char
+
+	tgt = C.CString(target) // TODO: need error check?
+	defer C.free(unsafe.Pointer(tgt))
+
+	x = C.hak_setoption(hak.c, C.HAK_OPT_MODLIBDIRS_BCSTR, unsafe.Pointer(tgt))
+	if x <= -1 { return hak.make_errinfo() }
+
+	return nil
 }
 
 func (hak *Hak) Ignite(memsize uintptr) error {
@@ -399,6 +482,16 @@ func (hak *Hak) Decode() error {
 	return nil
 }
 
+func (hak *Hak) RcvTick(enabled bool) {
+	var i C.int
+	if enabled { i = 1 } else { i = 0 }
+	C.hak_rcvtick(hak.c, i)
+}
+
+func (hak *Hak) RaiseTick() {
+	C.hak_raisetick(hak.c)
+}
+
 func (hak *Hak) get_errmsg() string {
 	return C.GoString(C.hak_geterrbmsg(hak.c))
 }

lib/comp.c

@@ -1134,6 +1134,7 @@ static int push_ctlblk (hak_t* hak, const hak_loc_t* errloc, hak_ctlblk_type_t t
 
 	HAK_MEMSET(&hak->c->ctlblk.info[new_depth], 0, HAK_SIZEOF(hak->c->ctlblk.info[new_depth]));
 	hak->c->ctlblk.info[new_depth]._type = type;
+	/*hak->c->ctlblk.info[new_depth].in_catch = 0; not needed for memset above */
 	hak->c->ctlblk.depth = new_depth;
 	return 0;
 }
@@ -2090,12 +2091,60 @@ static HAK_INLINE int emit_plus (hak_t* hak)
 #endif
 
 /* ========================================================================= */
+static int emit_ctlblk_unwind (hak_t* hak, hak_cnode_t* src, int stop_at_loop)
+{
+	hak_ooi_t i;
+
+	for (i = hak->c->ctlblk.depth; i > hak->c->funblk.info[hak->c->funblk.depth].ctlblk_base; --i)
+	{
+		switch (hak->c->ctlblk.info[i]._type)
+		{
+			case HAK_CTLBLK_TYPE_LOOP:
+				/* a loop block needs no unwinding instruction */
+				if (stop_at_loop) return 1; /* for break/continue inside loop */
+				break;
+
+			case HAK_CTLBLK_TYPE_TRY:
+				/* emit an instruction to exit from the try loop. when it is in the catch side. don't emit anything */
+				if (!hak->c->ctlblk.info[i].in_catch &&
+				    emit_byte_instruction(hak, HAK_CODE_TRY_EXIT, HAK_CNODE_GET_LOC(src)) <= -1) return -1;
+				break;
+
+			case HAK_CTLBLK_TYPE_CLASS:
+				/* emit an instruction to exit from the class definition scope being defined */
+				if (emit_byte_instruction(hak, HAK_CODE_CLASS_EXIT, HAK_CNODE_GET_LOC(src)) <= -1) return -1;
+				break;
+		}
+	}
+
+	return 0;
+}
+
+static void update_try_ctlblk_for_catch (hak_t* hak)
+{
+	hak_ooi_t i;
+
+	/* find the innermost try block info and mark that it's now in the catch block side */
+	for (i = hak->c->ctlblk.depth; i > hak->c->funblk.info[hak->c->funblk.depth].ctlblk_base; --i)
+	{
+		if (hak->c->ctlblk.info[i]._type == HAK_CTLBLK_TYPE_TRY)
+		{
+				hak->c->ctlblk.info[i].in_catch = 1;
+				return;
+		}
+	}
+
+	/* this must not happend. compile_catch() must not be invoked without
+	 * going through the enclosing TRY block first. */
+	HAK_ASSERT(hak, !"internal error - this must never happen");
+}
 
 static int compile_break (hak_t* hak, hak_cnode_t* src)
 {
 	/* (break) */
 	hak_cnode_t* cmd, * obj;
 	hak_ooi_t i;
+	int n;
 
 	HAK_ASSERT(hak, HAK_CNODE_IS_CONS(src));
 	HAK_ASSERT(hak, HAK_CNODE_IS_TYPED(HAK_CNODE_CONS_CAR(src), HAK_CNODE_BREAK));
@@ -2123,30 +2172,15 @@ static int compile_break (hak_t* hak, hak_cnode_t* src)
 		return -1;
 	}
 
-	for (i = hak->c->ctlblk.depth; i > hak->c->funblk.info[hak->c->funblk.depth].ctlblk_base; --i)
+	n = emit_ctlblk_unwind(hak, cmd, 1);
+	if (n <= -1) return -1;
+	if (n == 0)
 	{
-		switch (hak->c->ctlblk.info[i]._type)
+		hak_setsynerrbfmt(hak, HAK_SYNERR_BREAK, HAK_CNODE_GET_LOC(cmd),
-		{
-			case HAK_CTLBLK_TYPE_LOOP:
-				goto inside_loop;
-
-			case HAK_CTLBLK_TYPE_TRY:
-				/* emit an instruction to exit from the try loop. */
-				if (emit_byte_instruction(hak, HAK_CODE_TRY_EXIT, HAK_CNODE_GET_LOC(src)) <= -1) return -1;
-				break;
-
-			case HAK_CTLBLK_TYPE_CLASS:
-				/* emit an instruction to exit from the class definition scope being defined */
-				if (emit_byte_instruction(hak, HAK_CODE_CLASS_EXIT, HAK_CNODE_GET_LOC(src)) <= -1) return -1;
-				break;
-		}
-	}
-
-	hak_setsynerrbfmt(hak, HAK_SYNERR_BREAK, HAK_CNODE_GET_LOC(src),
 			"%.*js outside loop", HAK_CNODE_GET_TOKLEN(cmd), HAK_CNODE_GET_TOKPTR(cmd));
 		return -1;
+	}
 
-inside_loop:
 	for (i = hak->c->cfs.top; i >= 0; --i)
 	{
 		const hak_cframe_t* tcf;
@@ -2217,6 +2251,7 @@ static int compile_continue (hak_t* hak, hak_cnode_t* src)
 	/* (continue) */
 	hak_cnode_t* cmd, * obj;
 	hak_ooi_t i;
+	int n;
 
 	HAK_ASSERT(hak, HAK_CNODE_IS_CONS(src));
 	HAK_ASSERT(hak, HAK_CNODE_IS_TYPED(HAK_CNODE_CONS_CAR(src), HAK_CNODE_CONTINUE));
@@ -2244,29 +2279,15 @@ static int compile_continue (hak_t* hak, hak_cnode_t* src)
 		return -1;
 	}
 
-	for (i = hak->c->ctlblk.depth; i > hak->c->funblk.info[hak->c->funblk.depth].ctlblk_base; --i)
+	n = emit_ctlblk_unwind(hak, cmd, 1);
+	if (n <= -1) return -1;
+	if (n == 0)
 	{
-		switch (hak->c->ctlblk.info[i]._type)
+		hak_setsynerrbfmt(hak, HAK_SYNERR_BREAK, HAK_CNODE_GET_LOC(cmd),
-		{
-			case HAK_CTLBLK_TYPE_LOOP:
-				goto inside_loop;
-
-			case HAK_CTLBLK_TYPE_TRY:
-				/*must emit an instruction to exit from the try loop.*/
-				if (emit_byte_instruction(hak, HAK_CODE_TRY_EXIT, HAK_CNODE_GET_LOC(src)) <= -1) return -1;
-				break;
-
-			case HAK_CTLBLK_TYPE_CLASS:
-				if (emit_byte_instruction(hak, HAK_CODE_CLASS_EXIT, HAK_CNODE_GET_LOC(src)) <= -1) return -1;
-				break;
-		}
-	}
-
-	hak_setsynerrbfmt(hak, HAK_SYNERR_BREAK, HAK_CNODE_GET_LOC(src),
 			"%.*js outside loop", HAK_CNODE_GET_TOKLEN(cmd), HAK_CNODE_GET_TOKPTR(cmd));
 		return -1;
+	}
 
-inside_loop:
 	for (i = hak->c->cfs.top; i >= 0; --i)
 	{
 		const hak_cframe_t* tcf;
@@ -3968,7 +3989,6 @@ static int compile_return (hak_t* hak, hak_cnode_t* src, int ret_from_home)
 	hak_cnode_t* obj, * val;
 	hak_cframe_t* cf;
 	hak_funblk_info_t* fbi;
-	hak_ooi_t i;
 
 	HAK_ASSERT(hak, HAK_CNODE_IS_CONS(src));
 	HAK_ASSERT(hak, HAK_CNODE_IS_TYPED(HAK_CNODE_CONS_CAR(src), HAK_CNODE_RETURN) ||
@@ -3977,24 +3997,6 @@ static int compile_return (hak_t* hak, hak_cnode_t* src, int ret_from_home)
 	fbi = &hak->c->funblk.info[hak->c->funblk.depth];
 	obj = HAK_CNODE_CONS_CDR(src);
 
-	for (i = hak->c->ctlblk.depth; i > hak->c->funblk.info[hak->c->funblk.depth].ctlblk_base; --i)
-	{
-		switch (hak->c->ctlblk.info[i]._type)
-		{
-			case HAK_CTLBLK_TYPE_LOOP:
-				/* do nothing */
-				break;
-
-			case HAK_CTLBLK_TYPE_TRY:
-				if (emit_byte_instruction(hak, HAK_CODE_TRY_EXIT, HAK_CNODE_GET_LOC(src)) <= -1) return -1;
-				break;
-
-			case HAK_CTLBLK_TYPE_CLASS:
-				if (emit_byte_instruction(hak, HAK_CODE_CLASS_EXIT, HAK_CNODE_GET_LOC(src)) <= -1) return -1;
-				break;
-		}
-	}
-
 	if (fbi->tmpr_nrvars > 0)
 	{
 		hak_cnode_t* tmp = HAK_CNODE_CONS_CAR(src);
@@ -4016,6 +4018,9 @@ static int compile_return (hak_t* hak, hak_cnode_t* src, int ret_from_home)
 			return -1;
 		}
 
+		/* emit unwinding expression just before emitting the actual return instruction */
+		if (emit_ctlblk_unwind(hak, src, 0) <= -1) return -1;
+
 /* TODO: pop stack if this is not the first statement... */
 		if (emit_byte_instruction(hak, HAK_CODE_PUSH_RETURN_R, HAK_CNODE_GET_LOC(tmp)) <= -1) return -1;
 		POP_CFRAME(hak);
@@ -4502,6 +4507,7 @@ static HAK_INLINE int compile_catch (hak_t* hak)
 	/* produce an instruction to store the exception value to an exception variable pushed by the 'throw' instruction */
 	if (emit_variable_access(hak, VAR_ACCESS_POP, &vi, HAK_CNODE_GET_LOC(src)) <= -1) return -1;
 
+	update_try_ctlblk_for_catch(hak);
 	SWITCH_TOP_CFRAME(hak, COP_COMPILE_OBJECT_LIST, obj);
 
 	PUSH_SUBCFRAME(hak, COP_POST_CATCH, cmd);
@@ -7001,6 +7007,9 @@ static HAK_INLINE int emit_return (hak_t* hak)
 	HAK_ASSERT(hak, cf->opcode == COP_EMIT_RETURN);
 	HAK_ASSERT(hak, cf->operand != HAK_NULL);
 
+	/* emit unwinding expression just before emitting the actual return instruction */
+	if (emit_ctlblk_unwind(hak, cf->operand, 0) <= -1) return -1;
+
 	n = emit_byte_instruction(hak, (cf->u._return.from_home? HAK_CODE_RETURN_STACKTOP: HAK_CODE_RETURN_FROM_BLOCK), HAK_CNODE_GET_LOC(cf->operand));
 
 	POP_CFRAME(hak);

lib/exec.c

@@ -180,6 +180,8 @@ static void terminate_all_processes (hak_t* hak);
 		ap->exsp = HAK_SMOOI_TO_OOP(exsp); \
 	} while (0)
 
+/* normal stack top is the base of exstack */
+#define HAK_EXSTACK_GET_BASE(hak) HAK_OOP_TO_SMOOI(((hak)->processor->active)->st)
 #define HAK_EXSTACK_GET_ST(hak) HAK_OOP_TO_SMOOI(((hak)->processor->active)->exst)
 #define HAK_EXSTACK_GET_SP(hak) HAK_OOP_TO_SMOOI(((hak)->processor->active)->exsp)
 
@@ -235,6 +237,8 @@ static void terminate_all_processes (hak_t* hak);
 
 #define HAK_CLSTACK_CHOP(hak, clsp_) ((hak)->processor->active->clsp = HAK_SMOOI_TO_OOP(clsp_))
 
+/* exstack top is the base of clstack */
+#define HAK_CLSTACK_GET_BASE(hak) HAK_OOP_TO_SMOOI(((hak)->processor->active)->exst)
 #define HAK_CLSTACK_GET_ST(hak) HAK_OOP_TO_SMOOI(((hak)->processor->active)->clst)
 #define HAK_CLSTACK_GET_SP(hak) HAK_OOP_TO_SMOOI(((hak)->processor->active)->clsp)
 
@@ -385,6 +389,7 @@ static HAK_INLINE hak_oop_context_t make_context (hak_t* hak, hak_ooi_t ntmprs)
 	hak_oop_context_t ctx;
 
 	HAK_ASSERT(hak, ntmprs >= 0);
+
 	/*return (hak_oop_context_t)hak_allocoopobj(hak, HAK_BRAND_CONTEXT, HAK_CONTEXT_NAMED_INSTVARS + (hak_oow_t)ntmprs);*/
 	ctx = (hak_oop_context_t)hak_instantiate(hak, hak->c_block_context, HAK_NULL, ntmprs);
 
@@ -397,15 +402,11 @@ static HAK_INLINE hak_oop_context_t make_context (hak_t* hak, hak_ooi_t ntmprs)
 }
 
 #if defined(HAK_ENABLE_STACK_CONTEXT)
-#define HAK_USE_STACK_CONTEXT_FOR_FUNCTION 1
-#define HAK_USE_STACK_CONTEXT_FOR_BLOCK 1
 
-static HAK_INLINE hak_oop_t* alloc_frame_slots (hak_t* hak, hak_oow_t nslots)
+static HAK_INLINE hak_oop_t* alloc_frame_slots (hak_t* hak, hak_oop_process_t proc, hak_oow_t nslots)
 {
-	hak_oop_process_t proc;
 	hak_ooi_t sp, st;
 
-	proc = hak->processor->active;
 	HAK_ASSERT(hak, proc != hak->nil_process);
 
 	sp = HAK_OOP_TO_SMOOI(proc->fsp);
@@ -420,7 +421,7 @@ static HAK_INLINE hak_oop_t* alloc_frame_slots (hak_t* hak, hak_oow_t nslots)
 	return &proc->slot[sp + 1];
 }
 
-static HAK_INLINE hak_oop_context_t make_stack_context (hak_t* hak, hak_ooi_t ntmprs)
+static HAK_INLINE hak_oop_context_t make_stack_context (hak_t* hak, hak_oop_process_t proc, hak_ooi_t ntmprs)
 {
 	hak_oop_t* base;
 	hak_stack_context_t* sctx;
@@ -429,8 +430,8 @@ static HAK_INLINE hak_oop_context_t make_stack_context (hak_t* hak, hak_ooi_t nt
 
 	HAK_ASSERT(hak, ntmprs >= 0);
 
-	frame_base = HAK_OOP_TO_SMOOI(hak->processor->active->fsp);
+	frame_base = HAK_OOP_TO_SMOOI(proc->fsp);
-	base = alloc_frame_slots(hak, HAK_STACK_CONTEXT_NAMED_SLOTS + (hak_oow_t)ntmprs);
+	base = alloc_frame_slots(hak, proc, HAK_STACK_CONTEXT_NAMED_SLOTS + (hak_oow_t)ntmprs);
 	if (HAK_UNLIKELY(!base)) return HAK_NULL;
 
 	sctx = (hak_stack_context_t*)base;
@@ -453,30 +454,18 @@ static HAK_INLINE hak_oop_context_t make_stack_context (hak_t* hak, hak_ooi_t nt
 	sctx->slot_count = HAK_SMOOI_TO_OOP(ntmprs);
 	sctx->stack_base = HAK_SMOOI_TO_OOP(hak->sp);
 	sctx->frame_base = HAK_SMOOI_TO_OOP(frame_base);
-	sctx->heap_ctx = hak->_nil;
+	sctx->heap_ctx = hak->_nil; /* not reified yet. set to nil */
-	for (i = 0; i < ntmprs; i++) sctx->slot_base[i] = hak->_nil;
+	for (i = 0; i < ntmprs; i++) sctx->slot[i] = hak->_nil;
 	/* end of extra fields */
 
 	return (hak_oop_context_t)HAK_SMPTR_TO_OOP(sctx);
 }
 
-static HAK_INLINE hak_oop_context_t make_context_for_activation (hak_t* hak, hak_ooi_t ntmprs, int use_stack)
-{
-	if (use_stack)
-	{
-		hak_oop_context_t ctx = make_stack_context(hak, ntmprs);
-		if (HAK_UNLIKELY(!ctx)) return HAK_NULL;
-		return ctx;
-	}
-
-	return make_context(hak, ntmprs);
-}
-
 static HAK_INLINE hak_oop_context_t reify_context_ref (hak_t* hak, hak_oop_t ctx)
 {
 	if ((hak_oop_t)ctx == hak->_nil) return (hak_oop_context_t)ctx;
 	if (!HAK_CTX_IS_STACK(ctx)) return (hak_oop_context_t)ctx;
-	return hak_reify_stack_context(hak, HAK_CTX_TO_STACK(ctx));
+	return hak_reifystackcontext(hak, HAK_CTX_TO_STACK(ctx));
 }
 
 static HAK_INLINE void release_stack_context (hak_t* hak, hak_oop_t ctx)
@@ -488,13 +477,14 @@ static HAK_INLINE void release_stack_context (hak_t* hak, hak_oop_t ctx)
 	}
 }
 
-hak_oop_context_t hak_reify_stack_context (hak_t* hak, hak_stack_context_t* sctx)
+hak_oop_context_t hak_reifystackcontext (hak_t* hak, hak_stack_context_t* sctx)
 {
 	hak_oop_context_t ctx;
 	hak_oop_t heap_ctx;
 	hak_ooi_t slot_count;
 	hak_ooi_t i;
 
+	/* check if already reified */
 	heap_ctx = sctx->heap_ctx;
 	if ((hak_oop_t)heap_ctx != hak->_nil) return (hak_oop_context_t)heap_ctx;
 
@@ -502,6 +492,7 @@ hak_oop_context_t hak_reify_stack_context (hak_t* hak, hak_stack_context_t* sctx
 	ctx = make_context(hak, slot_count);
 	if (HAK_UNLIKELY(!ctx)) return HAK_NULL;
 
+	/* cache it */
 	sctx->heap_ctx = (hak_oop_t)ctx;
 
 	/* main fields */
@@ -524,26 +515,10 @@ hak_oop_context_t hak_reify_stack_context (hak_t* hak, hak_stack_context_t* sctx
 	if (HAK_UNLIKELY(!ctx->mthhome)) return HAK_NULL;
 	/* end of main fields */
 
-	for (i = 0; i < slot_count; i++) ctx->slot[i] = sctx->slot_base[i];
+	for (i = 0; i < slot_count; i++) ctx->slot[i] = sctx->slot[i];
 
 	return ctx;
 }
-#else
-
-#define HAK_USE_STACK_CONTEXT_FOR_FUNCTION 0
-#define HAK_USE_STACK_CONTEXT_FOR_BLOCK 0
-
-static HAK_INLINE hak_oop_context_t make_context_for_activation (hak_t* hak, hak_ooi_t ntmprs, int use_stack)
-{
-	(void)use_stack;
-	return make_context(hak, ntmprs);
-}
-
-static HAK_INLINE void release_stack_context (hak_t* hak, hak_oop_t ctx)
-{
-	(void)hak;
-	(void)ctx;
-}
 #endif
 
 static HAK_INLINE hak_oop_function_t make_function (hak_t* hak, hak_oow_t lfsize, const hak_oob_t* bptr, hak_oow_t blen, hak_dbgi_t* dbgi)
@@ -695,7 +670,7 @@ static HAK_INLINE void free_pid (hak_t* hak, hak_oop_process_t proc)
 	hak->proc_map_used--;
 }
 
-static hak_oop_process_t make_process (hak_t* hak, hak_oop_context_t c)
+static hak_oop_process_t make_process (hak_t* hak, hak_oop_context_t ctx)
 {
 	hak_oop_process_t proc;
 	hak_oow_t stksize, exstksize, clstksize, fstksize, maxsize;
@@ -715,32 +690,35 @@ static hak_oop_process_t make_process (hak_t* hak, hak_oop_context_t c)
 	if (hak->proc_map_free_first <= -1 && prepare_to_alloc_pid(hak) <= -1) return HAK_NULL;
 
 	stksize = hak->option.dfl_procstk_size; /* stack */
-	exstksize = 128; /* exception stack size */ /* TODO: make it configurable */
+	exstksize = hak->option.dfl_exstk_size; /* exception stack size */
-	clstksize = 64; /* class stack size */ /* TODO: make it configurable too */
+	clstksize = hak->option.dfl_clstk_size; /* class stack size */
 	fstksize = stksize; /* frame stack size */
 
 	maxsize = (HAK_TYPE_MAX(hak_ooi_t) - HAK_PROCESS_NAMED_INSTVARS) / 4;
 
 	if (stksize > maxsize) stksize = maxsize;
-	else if (stksize < 192) stksize = 192;
+	else if (stksize < HAK_MIN_PROCSTK_SIZE) stksize = HAK_MIN_PROCSTK_SIZE;
 
 	if (exstksize > maxsize) exstksize = maxsize;
-	else if (exstksize < 128) exstksize = 128;
+	else if (exstksize < HAK_MIN_EXSTK_SIZE) exstksize = HAK_MIN_EXSTK_SIZE;
 
 	if (clstksize > maxsize) clstksize = maxsize;
-	else if (clstksize < 32) clstksize = 32;
+	else if (clstksize < HAK_MIN_CLSTK_SIZE) clstksize = HAK_MIN_CLSTK_SIZE;
 
+#if defined(HAK_ENABLE_STACK_CONTEXT)
 	if (fstksize > maxsize) fstksize = maxsize;
-	else if (fstksize < 1024) fstksize = 1024;
+	else if (fstksize < HAK_MIN_FSTK_SIZE) fstksize = HAK_MIN_FSTK_SIZE;
+#else
+	fstksize = 0;
+#endif
 
-	hak_pushvolat(hak, (hak_oop_t*)&c);
+	hak_pushvolat(hak, (hak_oop_t*)&ctx);
 	proc = (hak_oop_process_t)hak_instantiate(hak, hak->c_process, HAK_NULL, stksize + exstksize + clstksize + fstksize);
 	hak_popvolat(hak);
 	if (HAK_UNLIKELY(!proc))
 	{
 		const hak_ooch_t* oldmsg = hak_backuperrmsg(hak);
-		hak_seterrbfmt(hak, hak->errnum,
+		hak_seterrbfmt(hak, hak->errnum, "unable to instantiate %O - %js", hak->c_process->name, oldmsg);
-			"unable to instantiate %O - %js", hak->c_process->name, oldmsg);
 		return HAK_NULL;
 	}
 
@@ -750,8 +728,11 @@ static hak_oop_process_t make_process (hak_t* hak, hak_oop_context_t c)
 	/* assign a process id to the process */
 	alloc_pid(hak, proc);
 
-	proc->initial_context = c;
+	/* [NIL CONTEXT]
-	proc->current_context = c;
+	 * if you pass hak->_nil for ctx since you don't have the context ready,
+	 * you must patch it after this function is over */
+	proc->initial_context = ctx;
+	proc->current_context = proc->initial_context;
 
 	/* stack */
 	proc->sp = HAK_SMOOI_TO_OOP(-1); /* no item */
@@ -768,8 +749,14 @@ static hak_oop_process_t make_process (hak_t* hak, hak_oop_context_t c)
 	/* frame stack */
 	proc->fsp = proc->clst; /* no item pushed yet */
 	proc->fst = HAK_SMOOI_TO_OOP(stksize + exstksize + clstksize + fstksize - 1);
+	/* the frame stack is not used when HAK_ENABLE_STACK_CONTEXT not defined.
+	 * but initialize it without the guard. fstksize is 0 anyways. */
 
-	HAK_ASSERT(hak, (hak_oop_t)HAK_CTX_GET_SENDER(hak, c) == hak->_nil);
+	/* [NIL CONTEXT]
+	 * this function allows hak->_nil for ctx but it puts the process object
+	 * in inconsistent state. the caller must patch the initial_context and
+	 * current_context fields as soon as possible */
+	HAK_ASSERT(hak, (hak_oop_t)ctx == hak->_nil || (hak_oop_t)HAK_CTX_GET_SENDER(hak, ctx) == hak->_nil);
 
 #if defined(HAK_DEBUG_VM_PROCESSOR)
 	HAK_LOG2(hak, HAK_LOG_IC | HAK_LOG_DEBUG, "Processor - process[%zd] **CREATED**->%hs\n", HAK_OOP_TO_SMOOI(proc->id), proc_state_to_string(HAK_OOP_TO_SMOOI(proc->state)));
@@ -1102,7 +1089,8 @@ static HAK_INLINE void reset_process_stack_pointers (hak_t* hak, hak_oop_process
 
 	proc->sp = HAK_SMOOI_TO_OOP(-1); /* invalidate the process stack */
 	proc->exsp = proc->st;
-	proc->clsp = proc->clst;
+	proc->clsp = proc->exst;
+	proc->fsp = proc->clst;
 }
 
 static void terminate_process (hak_t* hak, hak_oop_process_t proc)
@@ -1337,7 +1325,6 @@ static void yield_process (hak_t* hak, hak_oop_process_t proc)
 	}
 }
 
-
 static int async_signal_semaphore (hak_t* hak, hak_oop_semaphore_t sem)
 {
 #if 0
@@ -2150,7 +2137,7 @@ void hak_releaseiohandle (hak_t* hak, hak_ooi_t io_handle)
 
 /* ------------------------------------------------------------------------- */
 
-static int prepare_new_context (hak_t* hak, hak_oop_block_t op_blk, hak_ooi_t nargs, int nargs_offset, hak_ooi_t req_nrvars, int copy_args, int is_msgsend, hak_ooi_t msg_ivaroff, hak_oop_context_t* pnewctx)
+static int prepare_new_context (hak_t* hak, hak_oop_process_t proc, hak_oop_block_t op_blk, hak_ooi_t nargs, int nargs_offset, hak_ooi_t req_nrvars, int copy_args, int is_msgsend, hak_ooi_t msg_ivaroff, hak_oop_context_t* pnewctx)
 {
 	/* prepare a new block context for activation.
 	 * the passed block context becomes the base for a new block context. */
@@ -2191,7 +2178,11 @@ static int prepare_new_context (hak_t* hak, hak_oop_block_t op_blk, hak_ooi_t na
 
 	/* create a new block context to clone op_blk */
 	hak_pushvolat(hak, (hak_oop_t*)&op_blk);
-	blkctx = make_context_for_activation(hak, fixed_nargs + fblk_nrvars + fblk_nlvars + excess_nargs, HAK_USE_STACK_CONTEXT_FOR_BLOCK);
+#if defined(HAK_ENABLE_STACK_CONTEXT)
+	blkctx = make_stack_context(hak, proc, fixed_nargs + fblk_nrvars + fblk_nlvars + excess_nargs);
+#else
+	blkctx = make_context(hak, fixed_nargs + fblk_nrvars + fblk_nlvars + excess_nargs);
+#endif
 	hak_popvolat(hak);
 	if (HAK_UNLIKELY(!blkctx)) return -1;
 
@@ -2259,6 +2250,7 @@ static HAK_INLINE int __activate_block (hak_t* hak, hak_oop_block_t op_blk, hak_
 
 	x = prepare_new_context(
 		hak,
+		hak->processor->active,
 		op_blk,
 		nargs, /* nargs */
 		0, /* nargs_offset */
@@ -2330,7 +2322,11 @@ static int __activate_function (hak_t* hak, hak_oop_function_t op_func, hak_ooi_
 
 	/* create a new block context to clone op_func */
 	hak_pushvolat(hak, (hak_oop_t*)&op_func);
-	functx = make_context_for_activation(hak, fixed_nargs + nrvars + nlvars + excess_nargs, HAK_USE_STACK_CONTEXT_FOR_FUNCTION);
+#if defined(HAK_ENABLE_STACK_CONTEXT)
+	functx = make_stack_context(hak, hak->processor->active, fixed_nargs + nrvars + nlvars + excess_nargs);
+#else
+	functx = make_context(hak, fixed_nargs + nrvars + nlvars + excess_nargs);
+#endif
 	hak_popvolat(hak);
 	if (HAK_UNLIKELY(!functx)) return -1;
 
@@ -2718,9 +2714,11 @@ static HAK_INLINE int do_throw (hak_t* hak, hak_oop_t val, hak_ooi_t ip)
 
 	/* the below code is similar to do_return_from_block() */
 	hak->ip = -1; /* mark context dead. saved into hak->active_context->ip in SWITCH_ACTIVE_CONTEXT */
+
+#if defined(HAK_ENABLE_STACK_CONTEXT)
+	/* rewind the context stack */
 	{
 		hak_oop_context_t xctx;
-
 		xctx = hak->active_context;
 		while ((hak_oop_t)xctx != (hak_oop_t)catch_ctx && (hak_oop_t)xctx != hak->_nil)
 		{
@@ -2728,6 +2726,8 @@ static HAK_INLINE int do_throw (hak_t* hak, hak_oop_t val, hak_ooi_t ip)
 			xctx = (hak_oop_context_t)HAK_CTX_GET_SENDER(hak, xctx);
 		}
 	}
+#endif
+
 	SWITCH_ACTIVE_CONTEXT(hak, catch_ctx);
 	hak->ip = catch_ip; /* override the instruction pointer */
 
@@ -3323,13 +3323,21 @@ void hak_rcvtick (hak_t* hak, int enabled)
 
 void hak_raisetick (hak_t* hak)
 {
+#if defined(HAK_ATOMIC_ADD_FETCH)
+	HAK_ATOMIC_ADD_FETCH(&hak->tick, 1, HAK_ATOMIC_RELAXED);
+#else
 	hak->tick++;
+#endif
 }
 
 void hak_raise_gtick (int unused)
 {
 	/* this function is global and not bound to a specific instance. */
+#if defined(HAK_ATOMIC_ADD_FETCH)
+	HAK_ATOMIC_ADD_FETCH(&gtick, 1, HAK_ATOMIC_RELAXED);
+#else
 	gtick++;
+#endif
 }
 
 /* ------------------------------------------------------------------------- */
@@ -3425,7 +3433,9 @@ static HAK_INLINE int do_return_from_block (hak_t* hak)
 		/* it is a normal block return as the active block context
 		 * is not the initial context of a process */
 		hak->ip = -1; /* mark context dead. saved into hak->active_context->ip in SWITCH_ACTIVE_CONTEXT */
+	#if defined(HAK_ENABLE_STACK_CONTEXT)
 		release_stack_context(hak, (hak_oop_t)hak->active_context);
+	#endif
 		SWITCH_ACTIVE_CONTEXT(hak, (hak_oop_context_t)HAK_CTX_GET_SENDER(hak, hak->active_context));
 		return 0; /* normal return */
 	}
@@ -3591,7 +3601,9 @@ static HAK_INLINE int do_return_from_home (hak_t* hak, hak_oop_t return_value, h
 		while ((hak_oop_t)hak->active_context != (hak_oop_t)home)
 		{
 			hak->ip = -1; /* mark context dead. saved into hak->active_context->ip in SWITCH_ACTIVE_CONTEXT */
+		#if defined(HAK_ENABLE_STACK_CONTEXT)
 			release_stack_context(hak, (hak_oop_t)hak->active_context);
+		#endif
 			SWITCH_ACTIVE_CONTEXT(hak, (hak_oop_context_t)HAK_CTX_GET_SENDER(hak, hak->active_context));
 		}
 
@@ -3620,7 +3632,9 @@ static HAK_INLINE int do_return_from_home (hak_t* hak, hak_oop_t return_value, h
 
 		HAK_ASSERT(hak, (hak_oop_t)HAK_CTX_GET_SENDER(hak, hak->active_context) == (hak_oop_t)sender);
 		hak->ip = -1; /* mark context dead. saved into hak->active_context->ip in SWITCH_ACTIVE_CONTEXT */
+	#if defined(HAK_ENABLE_STACK_CONTEXT)
 		release_stack_context(hak, (hak_oop_t)hak->active_context);
+	#endif
 		SWITCH_ACTIVE_CONTEXT(hak, (hak_oop_context_t)HAK_CTX_GET_SENDER(hak, hak->active_context));
 		HAK_STACK_PUSH(hak, return_value);
 	}
@@ -4356,7 +4370,15 @@ static int execute (hak_t* hak)
 
 			case HAK_CODE_TRY_EXIT:
 				LOG_INST_0(hak, "try_exit");
-				/* TODO: stack underflow check? */
+				/* writing the condition this way would be more explicit.
+				 *  if (HAK_EXSTACK_GET_SP(hak) - HAK_EXSTACK_GET_BASE(hak) < 4)
+				 * it's simpler to use HAK_EXSTACK_IS_EMPTY() base PUSH, POP, POP_TO all move
+				 * exsp by exactly 4.  */
+				if (HAK_EXSTACK_IS_EMPTY(hak))
+				{
+					hak_seterrbfmt(hak, HAK_ESTKUNDFLW, "exception stack underflow");
+					goto oops_with_errmsg_supplement;
+				}
 				HAK_EXSTACK_POP(hak);
 				break;
 
@@ -4925,6 +4947,7 @@ hak_logbfmt(hak, HAK_LOG_STDERR, ">>>%O c->sc=%O sc=%O b2=%d b3=%d nivars=%d ncv
 
 			case HAK_CODE_PUSH_CONTEXT:
 				LOG_INST_0(hak, "push_context");
+/* TODO: error check? on HAK_CTX_TO_OOP? */
 				HAK_STACK_PUSH(hak, (hak_oop_t)HAK_CTX_TO_OOP(hak, hak->active_context));
 				break;
 
@@ -5345,7 +5368,7 @@ hak_logbfmt(hak, HAK_LOG_STDERR, ">>>%O c->sc=%O sc=%O b2=%d b3=%d nivars=%d ncv
 				if (HAK_CTX_IS_STACK(homectx))
 				{
 					hak_pushvolat(hak, (hak_oop_t*)&funcobj);
-					homectx = hak_reify_stack_context(hak, HAK_CTX_TO_STACK(homectx));
+					homectx = hak_reifystackcontext(hak, HAK_CTX_TO_STACK(homectx));
 					hak_popvolat(hak);
 					if (HAK_UNLIKELY(!homectx)) goto oops;
 					hak->active_context = homectx; /* because homectx is reified of hak->active_context */
@@ -5398,10 +5421,10 @@ hak_logbfmt(hak, HAK_LOG_STDERR, ">>>%O c->sc=%O sc=%O b2=%d b3=%d nivars=%d ncv
 				if (HAK_CTX_IS_STACK(homectx))
 				{
 					hak_pushvolat(hak, (hak_oop_t*)&blkobj);
-					homectx = hak_reify_stack_context(hak, HAK_CTX_TO_STACK(homectx));
+					homectx = hak_reifystackcontext(hak, HAK_CTX_TO_STACK(homectx));
 					hak_popvolat(hak);
 					if (HAK_UNLIKELY(!homectx)) goto oops;
-					hak->active_context = homectx; /* because homectx is reified of hak->active_context) */
+					hak->active_context = homectx; /* because homectx is reified of hak->active_context */
 					hak->processor->active->current_context = homectx;
 				}
 			#endif
@@ -5577,6 +5600,46 @@ hak_pfrc_t hak_pf_process_fork (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 		return HAK_PF_FAILURE;
 	}
 
+#if defined(HAK_ENABLE_STACK_CONTEXT)
+	/* a process requires a context to start with but create a new process first
+	 * to have a new context on the frame stack of the new process */
+	newprc = make_process(hak, (hak_oop_context_t)hak->_nil);
+	if (HAK_UNLIKELY(!newprc)) return HAK_PF_FAILURE;
+
+	hak_pushvolat(hak, (hak_oop_t*)&newprc);
+	x = prepare_new_context(
+		hak,
+		newprc,
+		blk,
+		nargs, /* nargs */
+		1, /* nargs_offset */
+		0, /* number of return variables expected */
+		1, /* copy_args */
+		0, /* is_msgsend */
+		0, /* msg_ivaroff */
+		&newctx);
+	hak_popvolat(hak);
+	if (HAK_UNLIKELY(x <= -1))
+	{
+		/* is it safe to terminate the process which doesn't have a proper context value
+		 * in initial_context and current_context? */
+		terminate_process(hak, newprc);
+		return HAK_PF_FAILURE;
+	}
+
+	HAK_ASSERT(hak, (hak_oop_t)HAK_CTX_GET_SENDER(hak, newctx) == hak->_nil);
+	HAK_CTX_SET_HOME(hak, newctx, (hak_oop_t)hak->_nil); /* the new context is the initial context in the new process. so reset it to nil */
+
+	HAK_ASSERT(hak, newprc->initial_context == (hak_oop_t)hak->_nil);
+	HAK_ASSERT(hak, newprc->initial_context == newprc->current_context);
+	newprc->initial_context = newctx;
+	newprc->current_context = newctx;
+#else
+	/* when stack context is disabled, create the context before
+	 * the process. so we put the process in consitent state
+	 * upon creation and also avoid the chance of making the process
+	 * stuck in some suspended state. */
+
 	/* (defun x(a b) ...)
 	 * (fork x 1 2)
 	 * among three arguments to fork, the first is the function block.
@@ -5585,6 +5648,7 @@ hak_pfrc_t hak_pf_process_fork (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 	 */
 	x = prepare_new_context(
 		hak,
+		hak->processor->active,
 		blk,
 		nargs, /* nargs */
 		1, /* nargs_offset */
@@ -5602,6 +5666,7 @@ hak_pfrc_t hak_pf_process_fork (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 	newprc = make_process(hak, newctx);
 	hak_popvolat(hak);
 	if (HAK_UNLIKELY(!newprc)) return HAK_PF_FAILURE;
+#endif
 
 	chain_into_processor(hak, newprc, HAK_PROCESS_STATE_RUNNABLE);
 
@@ -5620,6 +5685,11 @@ hak_pfrc_t hak_pf_process_resume (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 		return HAK_PF_FAILURE;
 	}
 
+	/* [SPECIAL CASE]
+	 * resume_process changes the the active process.
+	 * calling this after resume_process() pollutes a wrong stack. place it here */
+	HAK_STACK_SETRET(hak, nargs, (hak_oop_t)prc);
+
 	resume_process(hak, prc);
 	return HAK_PF_SUCCESS;
 }
@@ -5642,6 +5712,11 @@ hak_pfrc_t hak_pf_process_suspend (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 		prc = hak->processor->active;
 	}
 
+	/* [SPECIAL CASE]
+	 * suspend_process changes the the active process.
+	 * calling this after suspend_process() pollutes a wrong stack. place it here */
+	HAK_STACK_SETRET(hak, nargs, (hak_oop_t)prc);
+
 	suspend_process(hak, prc);
 	return HAK_PF_SUCCESS;
 }
@@ -5664,18 +5739,33 @@ hak_pfrc_t hak_pf_process_terminate (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs
 		prc = hak->processor->active;
 	}
 
+	/* [SPECIAL CASE]
+	 * terminate_process changes the the active process.
+	 * calling this after terminate_process() pollutes a wrong stack. place it here */
+	HAK_STACK_SETRET(hak, nargs, (hak_oop_t)prc);
+
 	terminate_process(hak, prc);
 	return  HAK_PF_SUCCESS;
 }
 
 hak_pfrc_t hak_pf_process_terminate_all (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 {
+	/* [SPECIAL CASE]
+	 * terminate_all_processes changes the the active process.
+	 * calling this after terminate_all_processes() pollutes a wrong stack. place it here */
+	HAK_STACK_SETRET(hak, nargs, hak->_nil);
+
 	terminate_all_processes(hak);
 	return HAK_PF_SUCCESS;
 }
 
 hak_pfrc_t hak_pf_process_yield (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 {
+	/* [SPECIAL CASE]
+	 * yield_process changes the the active process.
+	 * calling this after yield_process() pollutes a wrong stack. place it here */
+	HAK_STACK_SETRET(hak, nargs, hak->_nil);
+
 	yield_process(hak, hak->processor->active);
 	return HAK_PF_SUCCESS;
 }
@@ -5695,7 +5785,22 @@ hak_pfrc_t hak_pf_semaphore_new (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 		return HAK_PF_FAILURE;
 	}
 
+	if (nargs >= 1)
+	{
+		hak_oop_t tmp;
+		tmp = HAK_STACK_GETARG(hak, nargs, 0);
+		if (!HAK_OOP_IS_SMOOI(tmp))
+		{
+			hak_seterrbfmt(hak, HAK_EINVAL, "invalid semaphore count - %O", tmp);
+			return HAK_PF_FAILURE;
+		}
+		sem->count = tmp;
+	}
+	else
+	{
 		sem->count = HAK_SMOOI_TO_OOP(0);
+	}
+
 /* TODO: sem->signal_action? */
 	/* other fields are all set to nil */
 

lib/gc.c

@@ -880,10 +880,12 @@ static HAK_INLINE void gc_ms_scan_stack (hak_t* hak)
 				HAK_ASSERT(hak, ll < (hak_ooi_t)(HAK_OBJ_GET_SIZE(oop) - HAK_PROCESS_NAMED_INSTVARS));
 				for (i = HAK_OOP_TO_SMOOI(proc->exst) + 1; i <= ll; i++) gc_ms_mark_object(hak, proc->slot[i]);
 
+			#if defined(HAK_ENABLE_STACK_CONTEXT)
 				/* frame stack */
 				ll = HAK_OOP_TO_SMOOI(proc->fsp);
 				HAK_ASSERT(hak, ll < (hak_ooi_t)(HAK_OBJ_GET_SIZE(oop) - HAK_PROCESS_NAMED_INSTVARS));
 				for (i = HAK_OOP_TO_SMOOI(proc->clst) + 1; i <= ll; i++) gc_ms_mark_object(hak, proc->slot[i]);
+			#endif
 			}
 			else
 			{

lib/hak-cfg.h.in

@@ -226,6 +226,9 @@
 /* Define to 1 if you have the <errno.h> header file. */
 #undef HAVE_ERRNO_H
 
+/* Define to 1 if \u encodes properly */
+#undef HAVE_ESCAPE_U
+
 /* Define to 1 if you have the <execinfo.h> header file. */
 #undef HAVE_EXECINFO_H
 

lib/hak-cmn.h

@@ -1084,6 +1084,52 @@ typedef struct hak_t hak_t;
 		#define HAK_HAVE_BUILTIN_CLZLL
 	#endif
 
+	#if __has_builtin(__atomic_compare_exchange_n)
+		#define HAK_HAVE_ATOMIC_COMPARE_EXCHANGE_N
+	#endif
+
+	#if __has_builtin(__atomic_exchange_n)
+		#define HAK_HAVE_ATOMIC_EXCHANGE_N
+	#endif
+
+	#if __has_builtin(__atomic_fetch_add)
+		#define HAK_HAVE_ATOMIC_FETCH_ADD
+	#endif
+	#if __has_builtin(__atomic_add_fetch)
+		#define HAK_HAVE_ATOMIC_ADD_FETCH
+	#endif
+	#if __has_builtin(__atomic_fetch_and)
+		#define HAK_HAVE_ATOMIC_FETCH_AND
+	#endif
+	#if __has_builtin(__atomic_and_fetch)
+		#define HAK_HAVE_ATOMIC_AND_FETCH
+	#endif
+	#if __has_builtin(__atomic_fetch_or)
+		#define HAK_HAVE_ATOMIC_FETCH_OR
+	#endif
+	#if __has_builtin(__atomic_or_fetch)
+		#define HAK_HAVE_ATOMIC_OR_FETCH
+	#endif
+	#if __has_builtin(__atomic_fetch_sub)
+		#define HAK_HAVE_ATOMIC_FETCH_SUB
+	#endif
+	#if __has_builtin(__atomic_sub_fetch)
+		#define HAK_HAVE_ATOMIC_SUB_FETCH
+	#endif
+	#if __has_builtin(__atomic_fetch_xor)
+		#define HAK_HAVE_ATOMIC_FETCH_XOR
+	#endif
+	#if __has_builtin(__atomic_xor_fetch)
+		#define HAK_HAVE_ATOMIC_XOR_FETCH
+	#endif
+
+	#if __has_builtin(__atomic_load_n)
+		#define HAK_HAVE_ATOMIC_LOAD_N
+	#endif
+	#if __has_builtin(__atomic_store_n)
+		#define HAK_HAVE_ATOMIC_STORE_N
+	#endif
+
 	#if __has_builtin(__builtin_uadd_overflow)
 		#define HAK_HAVE_BUILTIN_UADD_OVERFLOW
 	#endif
@@ -1158,11 +1204,19 @@ typedef struct hak_t hak_t;
 	#endif
 
 #elif defined(__GNUC__) && defined(__GNUC_MINOR__)
-
 	#if (__GNUC__ >= 4)
+		#define HAK_HAVE_SYNC_FETCH_AND_ADD
+		#define HAK_HAVE_SYNC_ADD_AND_FETCH
+		#define HAK_HAVE_SYNC_FETCH_AND_AND
+		#define HAK_HAVE_SYNC_AND_AND_FETCH
+		#define HAK_HAVE_SYNC_FETCH_AND_OR
+		#define HAK_HAVE_SYNC_OR_AND_FETCH
+		#define HAK_HAVE_SYNC_FETCH_AND_SUB
+		#define HAK_HAVE_SYNC_SUB_AND_FETCH
+		#define HAK_HAVE_SYNC_FETCH_AND_XOR
+		#define HAK_HAVE_SYNC_XOR_AND_FETCH
 		#define HAK_HAVE_SYNC_LOCK_TEST_AND_SET
 		#define HAK_HAVE_SYNC_LOCK_RELEASE
-
 		#define HAK_HAVE_SYNC_SYNCHRONIZE
 		#define HAK_HAVE_SYNC_BOOL_COMPARE_AND_SWAP
 		#define HAK_HAVE_SYNC_VAL_COMPARE_AND_SWAP
@@ -1194,6 +1248,19 @@ typedef struct hak_t hak_t;
 		#define HAK_HAVE_BUILTIN_SMULLL_OVERFLOW
 	#endif
 
+	#if (__GNUC__ >= 5) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7)
+		#define HAK_HAVE_ATOMIC_FETCH_ADD
+		#define HAK_HAVE_ATOMIC_ADD_FETCH
+		#define HAK_HAVE_ATOMIC_FETCH_AND
+		#define HAK_HAVE_ATOMIC_AND_FETCH
+		#define HAK_HAVE_ATOMIC_FETCH_OR
+		#define HAK_HAVE_ATOMIC_OR_FETCH
+		#define HAK_HAVE_ATOMIC_FETCH_SUB
+		#define HAK_HAVE_ATOMIC_SUB_FETCH
+		#define HAK_HAVE_ATOMIC_FETCH_XOR
+		#define HAK_HAVE_ATOMIC_XOR_FETCH
+	#endif
+
 	#if (__GNUC__ >= 5) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)
 		/* 4.8.0 or later */
 		#define HAK_HAVE_BUILTIN_BSWAP16
@@ -1207,6 +1274,12 @@ typedef struct hak_t hak_t;
 
 #endif
 
+#if defined(__has_builtin)
+#	define HAK_HAS_BUILTIN(v) __has_builtin(v)
+#else
+#	define HAK_HAS_BUILTIN(v) 0
+#endif
+
 #if defined(HAK_HAVE_BUILTIN_EXPECT)
 #	define HAK_LIKELY(x) (__builtin_expect(!!(x),1))
 #	define HAK_UNLIKELY(x) (__builtin_expect(!!(x),0))
@@ -1215,6 +1288,117 @@ typedef struct hak_t hak_t;
 #	define HAK_UNLIKELY(x) (x)
 #endif
 
+#if defined(HAK_HAVE_ATOMIC_EXCHANGE_N)
+#	define HAK_ATOMIC_EXCHANGE(ptr,val,mo) __atomic_exchange_n((ptr),(val),(mo))
+#elif defined(HAK_HAVE_SYNC_LOCK_TEST_AND_SET)
+#	define HAK_ATOMIC_EXCHANGE(ptr,val,mo) __sync_lock_test_and_set((ptr),(val))
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_FETCH_ADD)
+#	define HAK_ATOMIC_FETCH_ADD(ptr,val,mo) __atomic_fetch_add((ptr),(val),(mo))
+#elif defined(HAK_HAVE_SYNC_FETCH_AND_ADD)
+#	define HAK_ATOMIC_FETCH_ADD(ptr,val,mo) __sync_fetch_and_add((ptr),(val))
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_ADD_FETCH)
+#	define HAK_ATOMIC_ADD_FETCH(ptr,val,mo) __atomic_add_fetch((ptr),(val),(mo))
+#elif defined(HAK_HAVE_SYNC_ADD_AND_FETCH)
+#	define HAK_ATOMIC_ADD_FETCH(ptr,val,mo) __sync_add_and_fetch((ptr),(val))
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_FETCH_AND)
+#	define HAK_ATOMIC_FETCH_AND(ptr,val,mo) __atomic_fetch_and((ptr),(val),(mo))
+#elif defined(HAK_HAVE_SYNC_FETCH_AND_AND)
+#	define HAK_ATOMIC_FETCH_AND(ptr,val,mo) __sync_fetch_and_and((ptr),(val))
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_AND_FETCH)
+#	define HAK_ATOMIC_AND_FETCH(ptr,val,mo) __atomic_and_fetch((ptr),(val),(mo))
+#elif defined(HAK_HAVE_SYNC_AND_AND_FETCH)
+#	define HAK_ATOMIC_AND_FETCH(ptr,val,mo) __sync_and_and_fetch((ptr),(val))
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_FETCH_OR)
+#	define HAK_ATOMIC_FETCH_OR(ptr,val,mo) __atomic_fetch_or((ptr),(val),(mo))
+#elif defined(HAK_HAVE_SYNC_FETCH_AND_OR)
+#	define HAK_ATOMIC_FETCH_OR(ptr,val,mo) __sync_fetch_and_or((ptr),(val))
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_OR_FETCH)
+#	define HAK_ATOMIC_OR_FETCH(ptr,val,mo) __atomic_or_fetch((ptr),(val),(mo))
+#elif defined(HAK_HAVE_SYNC_OR_AND_FETCH)
+#	define HAK_ATOMIC_OR_FETCH(ptr,val,mo) __sync_or_and_fetch((ptr),(val))
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_FETCH_SUB)
+#	define HAK_ATOMIC_FETCH_SUB(ptr,val,mo) __atomic_fetch_sub((ptr),(val),(mo))
+#elif defined(HAK_HAVE_SYNC_FETCH_AND_SUB)
+#	define HAK_ATOMIC_FETCH_SUB(ptr,val,mo) __sync_fetch_and_sub((ptr),(val))
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_SUB_FETCH)
+#	define HAK_ATOMIC_SUB_FETCH(ptr,val,mo) __atomic_sub_fetch((ptr),(val),(mo))
+#elif defined(HAK_HAVE_SYNC_SUB_AND_FETCH)
+#	define HAK_ATOMIC_SUB_FETCH(ptr,val,mo) __sync_sub_and_fetch((ptr),(val))
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_FETCH_XOR)
+#	define HAK_ATOMIC_FETCH_XOR(ptr,val,mo) __atomic_fetch_xor((ptr),(val),(mo))
+#elif defined(HAK_HAVE_SYNC_FETCH_AND_XOR)
+#	define HAK_ATOMIC_FETCH_XOR(ptr,val,mo) __sync_fetch_and_xor((ptr),(val))
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_XOR_FETCH)
+#	define HAK_ATOMIC_XOR_FETCH(ptr,val,mo) __atomic_xor_fetch((ptr),(val),(mo))
+#elif defined(HAK_HAVE_SYNC_XOR_AND_FETCH)
+#	define HAK_ATOMIC_XOR_FETCH(ptr,val,mo) __sync_xor_and_fetch((ptr),(val))
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_LOAD_N)
+#	define HAK_ATOMIC_LOAD(ptr,mo) __atomic_load_n((ptr),(mo))
+#elif defined(HAK_HAVE_SYNC_FETCH_AND_OR)
+#	define HAK_ATOMIC_LOAD(ptr,mo) __sync_fetch_and_or((ptr),0)
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_STORE_N)
+#	define HAK_ATOMIC_STORE(ptr,val,mo) __atomic_store_n((ptr),(val),(mo))
+#elif defined(HAK_HAVE_SYNC_LOCK_TEST_AND_SET) && defined(HAK_HAVE_SYNC_SYNCHRONIZE)
+#	define HAK_ATOMIC_STORE(ptr,val,mo) do { __sync_lock_test_and_set((ptr),(val)); __sync_synchronize(); } while(0)
+#endif
+
+#if defined(HAK_HAVE_ATOMIC_COMPARE_EXCHANGE_N)
+#	define HAK_ATOMIC_CAS_BOOL(ptr, expected_ptr, desired, memmod_succ, memmod_fail) \
+		__atomic_compare_exchange_n((ptr), (expected_ptr), (desired), 0, (memmod_succ), (memmod_fail))
+#	define HAK_ATOMIC_CAS_BOOL_YIELD_OLDVAL
+#elif defined(HAK_HAVE_SYNC_BOOL_COMPARE_AND_SWAP)
+#	define HAK_ATOMIC_CAS_BOOL(ptr, expected_ptr, desired, memmod_succ, memmod_fail) \
+		__sync_bool_compare_and_swap((ptr), *(expected_ptr), (desired))
+#endif
+
+#if defined(__ATOMIC_RELAXED)
+#	define HAK_ATOMIC_RELAXED __ATOMIC_RELAXED
+#else
+#	define HAK_ATOMIC_RELAXED 0
+#endif
+
+#if defined(__ATOMIC_ACQUIRE)
+#	define HAK_ATOMIC_ACQUIRE __ATOMIC_ACQUIRE
+#else
+#	define HAK_ATOMIC_ACQUIRE 2
+#endif
+
+#if defined(__ATOMIC_RELEASE)
+#	define HAK_ATOMIC_RELEASE __ATOMIC_RELEASE
+#else
+#	define HAK_ATOMIC_RELEASE 3
+#endif
+
+#if defined(__ATOMIC_ACQ_REL)
+#	define HAK_ATOMIC_ACQ_REL __ATOMIC_ACQ_REL
+#else
+#	define HAK_ATOMIC_ACQ_REL 4
+#endif
+
 /* =========================================================================
  * STATIC ASSERTION
  * =========================================================================*/

lib/hak-hnd.h

@@ -157,8 +157,6 @@ struct hak_hnd_t
 	hak_hnd_t* next;
 };
 
-typedef struct hak_hndtab_t hak_hndtab_t;
-
 /* ========================================================================= */
 /* THE UNIFORM I/O CONTRACT                                                  */
 /* ========================================================================= */

lib/hak-prv.h

@@ -48,7 +48,9 @@
 /* enable floating-pointer number support in the basic formatting functions */
 #define HAK_ENABLE_FLTFMT
 
+#if !defined(HAK_DISABLE_STACK_CONTEXT)
 #define HAK_ENABLE_STACK_CONTEXT
+#endif
 
 #if defined(HAK_ENABLE_STACK_CONTEXT)
 
@@ -57,6 +59,7 @@
 typedef struct hak_stack_context_t hak_stack_context_t;
 struct hak_stack_context_t
 {
+	/* mirrored fields of hak_context_t defined in hak.h */
 	hak_oop_t req_nrets;
 	hak_oop_t attr_mask;
 	hak_oop_t name;
@@ -69,22 +72,24 @@ struct hak_stack_context_t
 	hak_oop_t ivaroff;
 	hak_oop_t owner;
 
+	/* extra fields for house-keeping */
 	hak_oop_t slot_count;
 	hak_oop_t stack_base;
 	hak_oop_t frame_base;
-	hak_oop_t heap_ctx;
+	hak_oop_t heap_ctx; /* set to non-nil if reified */
 
-	hak_oop_t slot_base[1];
+	/* space for arguments, local variables, return variables, etc after the fixed fields like in hak_context_t */
+	hak_oop_t slot[1];
 };
 
 /*#define HAK_STACK_CONTEXT_NAMED_SLOTS (HAK_SIZEOF(hak_stack_context_t) / HAK_SIZEOF(hak_oop_t))*/
-#define HAK_STACK_CONTEXT_NAMED_SLOTS (15) /* excludes slot_base */
+#define HAK_STACK_CONTEXT_NAMED_SLOTS (15) /* excludes slot */
 
 #if defined(__cplusplus)
 extern "C" {
 #endif
 
-hak_oop_context_t hak_reify_stack_context (hak_t* hak, hak_stack_context_t* sctx);
+hak_oop_context_t hak_reifystackcontext (hak_t* hak, hak_stack_context_t* sctx);
 
 #if defined(__cplusplus)
 }
@@ -92,33 +97,20 @@ hak_oop_context_t hak_reify_stack_context (hak_t* hak, hak_stack_context_t* sctx
 
 #define HAK_CTX_IS_STACK(ctx) (HAK_OOP_IS_SMPTR(ctx))
 #define HAK_CTX_TO_STACK(ctx) ((hak_stack_context_t*)HAK_OOP_TO_SMPTR(ctx))
-#define HAK_CTX_TO_OOP(hak, ctx) (HAK_CTX_IS_STACK(ctx)? hak_reify_stack_context((hak), HAK_CTX_TO_STACK(ctx)): (hak_oop_context_t)(ctx))
+#define HAK_CTX_TO_OOP(hak, ctx) (HAK_CTX_IS_STACK(ctx)? hak_reifystackcontext((hak), HAK_CTX_TO_STACK(ctx)): (hak_oop_context_t)(ctx))
 
-#if 0
+#define HAK_CTX_SLOT(hak, ctx) (HAK_CTX_IS_STACK(ctx)? HAK_CTX_TO_STACK(ctx)->slot: ((hak_oop_context_t)(ctx))->slot)
-#define HAK_CTX_SLOT(hak, ctx) (HAK_CTX_IS_STACK(ctx)? (hak_oop_t*)HAK_OOP_TO_SMPTR(HAK_CTX_TO_STACK(ctx)->slot_base) : ((hak_oop_context_t)(ctx))->slot)
-#define HAK_CTX_SLOT_AT(hak, ctx, idx) (HAK_CTX_IS_STACK(ctx)? ((hak_oop_t*)HAK_OOP_TO_SMPTR(HAK_CTX_TO_STACK(ctx)->slot_base))[idx] : ((hak_oop_context_t)(ctx))->slot[idx])
-#define HAK_CTX_SLOT_AT_PUT(hak, ctx, idx, val) \
-do { \
-	if (HAK_CTX_IS_STACK(ctx)) \
-		((hak_oop_t*)HAK_OOP_TO_SMPTR(HAK_CTX_TO_STACK(ctx)->slot_base))[idx] = (val); \
-	else \
-		((hak_oop_context_t)(ctx))->slot[idx] = (val); \
-} while(0)
-#else
-
-#define HAK_CTX_SLOT(hak, ctx) (HAK_CTX_IS_STACK(ctx)? HAK_CTX_TO_STACK(ctx)->slot_base : ((hak_oop_context_t)(ctx))->slot)
 
 #define HAK_CTX_SLOT_AT(hak, ctx, idx) \
-	(HAK_CTX_IS_STACK(ctx)? HAK_CTX_TO_STACK(ctx)->slot_base[idx]: ((hak_oop_context_t)(ctx))->slot[idx])
+	(HAK_CTX_IS_STACK(ctx)? HAK_CTX_TO_STACK(ctx)->slot[idx]: ((hak_oop_context_t)(ctx))->slot[idx])
 
 #define HAK_CTX_SLOT_AT_PUT(hak, ctx, idx, val) \
 do { \
 	if (HAK_CTX_IS_STACK(ctx)) \
-		HAK_CTX_TO_STACK(ctx)->slot_base[idx] = (val); \
+		HAK_CTX_TO_STACK(ctx)->slot[idx] = (val); \
 	else \
 		((hak_oop_context_t)(ctx))->slot[idx] = (val); \
 } while(0)
-#endif
 
 #define HAK_CTX_GET_REQNRETS(hak, ctx) (HAK_CTX_IS_STACK(ctx)? HAK_CTX_TO_STACK(ctx)->req_nrets : ((hak_oop_context_t)(ctx))->req_nrets)
 #define HAK_CTX_SET_REQNRETS(hak, ctx, v) do { if (HAK_CTX_IS_STACK(ctx)) HAK_CTX_TO_STACK(ctx)->req_nrets = (v); else ((hak_oop_context_t)(ctx))->req_nrets = (v); } while (0)
@@ -517,6 +509,7 @@ enum hak_tok_type_t
 	HAK_TOK_EOL,       /* end of line */
 
 	HAK_TOK_INCLUDE,
+	HAK_TOK_INCLUDE_ONCE,
 	HAK_TOK_PRAGMA
 };
 typedef enum hak_tok_type_t hak_tok_type_t;
@@ -855,6 +848,7 @@ typedef enum hak_ctlblk_type_t hak_ctlblk_type_t;
 struct hak_ctlblk_info_t
 {
 	hak_ctlblk_type_t _type;
+	int in_catch; /* used for HAK_CTLBLK_TYPE_TRY only */
 };
 typedef struct hak_ctlblk_info_t hak_ctlblk_info_t;
 
@@ -2247,6 +2241,8 @@ hak_pfrc_t hak_pf_nqv (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
 hak_pfrc_t hak_pf_nql (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
 hak_pfrc_t hak_pf_nqk (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
 
+hak_pfrc_t hak_pf_object_new (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
+
 hak_pfrc_t hak_pf_process_current (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
 hak_pfrc_t hak_pf_process_fork (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
 hak_pfrc_t hak_pf_process_resume (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
@@ -2269,6 +2265,15 @@ hak_pfrc_t hak_pf_semaphore_group_add_semaphore (hak_t* hak, hak_mod_t* mod, hak
 hak_pfrc_t hak_pf_semaphore_group_remove_semaphore (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
 hak_pfrc_t hak_pf_semaphore_group_wait (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
 
+/* the signal primitives live in prim.c but are registered by the sys module,
+ * which reaches them as sys.sig-getfd, sys.sig-get, sys.sig-set, sys.sig-catch
+ * and sys.sig-uncatch */
+hak_pfrc_t hak_pf_system_get_sigfd (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
+hak_pfrc_t hak_pf_system_get_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
+hak_pfrc_t hak_pf_system_set_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
+hak_pfrc_t hak_pf_system_catch_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
+hak_pfrc_t hak_pf_system_uncatch_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs);
+
 /* ========================================================================= */
 /* std.c                                                                    */
 /* ========================================================================= */

lib/hak.c

@@ -150,6 +150,8 @@ int hak_init (hak_t* hak, hak_mmgr_t* mmgr, const hak_vmprim_t* vmprim)
 	hak->option.dfl_symtab_size = HAK_DFL_SYMTAB_SIZE;
 	hak->option.dfl_sysdic_size = HAK_DFL_SYSDIC_SIZE;
 	hak->option.dfl_procstk_size = HAK_DFL_PROCSTK_SIZE;
+	hak->option.dfl_exstk_size = HAK_DFL_EXSTK_SIZE;
+	hak->option.dfl_clstk_size = HAK_DFL_CLSTK_SIZE;
 #if defined(HAK_BUILD_DEBUG)
 	hak->option.karatsuba_cutoff = HAK_KARATSUBA_CUTOFF; /* this won't be used when NDEBUG is set */
 #endif
@@ -367,9 +369,39 @@ void hak_fini (hak_t* hak)
 		hak->option.log_target_b = HAK_NULL;
 	}
 
+	/* destroy dynamically allocated options */
 	for (i = 0; i < HAK_COUNTOF(hak->option.mod); i++)
 	{
-		if (hak->option.mod[i].ptr) hak_freemem(hak, hak->option.mod[i].ptr);
+		if (hak->option.mod[i].ptr)
+		{
+			hak_freemem(hak, hak->option.mod[i].ptr);
+			hak->option.mod[i].ptr = HAK_NULL;
+			hak->option.mod[i].len = 0;
+		}
+	}
+
+	if (hak->option.modlibdirs_b)
+	{
+		hak_freemem(hak, hak->option.modlibdirs_b);
+		hak->option.modlibdirs_b = HAK_NULL;
+	}
+
+	if (hak->option.modlibdirs_u)
+	{
+		hak_freemem(hak, hak->option.modlibdirs_u);
+		hak->option.modlibdirs_u = HAK_NULL;
+	}
+
+	if (hak->option.incdirs_b)
+	{
+		hak_freemem(hak, hak->option.incdirs_b);
+		hak->option.incdirs_b = HAK_NULL;
+	}
+
+	if (hak->option.incdirs_u)
+	{
+		hak_freemem(hak, hak->option.incdirs_u);
+		hak->option.incdirs_u = HAK_NULL;
 	}
 
 	if (hak->inttostr.xbuf.ptr)
@@ -447,28 +479,74 @@ static int dup_str_opt (hak_t* hak, const hak_ooch_t* value, hak_oocs_t* tmp)
 	return 0;
 }
 
+/* Store a string option in both representations at once.
+ *
+ * The consumers of these options are byte oriented - dlopen() and fopen() -
+ * so the bch form is what gets used, and converting once here saves a
+ * conversion on every module load and every include attempt. The uch form is
+ * kept so getoption can answer in either encoding without allocating.
+ *
+ * Both conversions are done before either slot is replaced, so a failure
+ * leaves the previous value in place rather than half-updating it. */
+static int set_dual_str_opt (hak_t* hak, const void* value, int value_is_bch, hak_bch_t** bp, hak_uch_t** up)
+{
+	hak_bch_t* v_b;
+	hak_uch_t* v_u;
+
+	if (value_is_bch)
+	{
+		v_b = hak_dupbcstr(hak, (const hak_bch_t*)value, HAK_NULL);
+		if (HAK_UNLIKELY(!v_b)) return -1;
+
+		v_u = hak_dupbtoucstr(hak, (const hak_bch_t*)value, HAK_NULL);
+		if (HAK_UNLIKELY(!v_u))
+		{
+			hak_freemem(hak, v_b);
+			return -1;
+		}
+	}
+	else
+	{
+		v_u = hak_dupucstr(hak, (const hak_uch_t*)value, HAK_NULL);
+		if (HAK_UNLIKELY(!v_u)) return -1;
+
+		v_b = hak_duputobcstr(hak, (const hak_uch_t*)value, HAK_NULL);
+		if (HAK_UNLIKELY(!v_b))
+		{
+			hak_freemem(hak, v_u);
+			return -1;
+		}
+	}
+
+	if (*bp) hak_freemem(hak, *bp);
+	if (*up) hak_freemem(hak, *up);
+	*bp = v_b;
+	*up = v_u;
+	return 0;
+}
+
 int hak_setoption (hak_t* hak, hak_option_t id, const void* value)
 {
 	hak_cb_t* cb;
 
 	switch (id)
 	{
-		case HAK_TRAIT:
+		case HAK_OPT_TRAIT:
 			hak->option.trait = *(const hak_bitmask_t*)value;
 		#if defined(HAK_BUILD_DEBUG)
 			hak->option.karatsuba_cutoff = ((hak->option.trait & HAK_TRAIT_DEBUG_BIGINT)? HAK_KARATSUBA_CUTOFF_DEBUG: HAK_KARATSUBA_CUTOFF);
 		#endif
 			break;
 
-		case HAK_LOG_MASK:
+		case HAK_OPT_LOG_MASK:
 			hak->option.log_mask = *(const hak_bitmask_t*)value;
 			break;
 
-		case HAK_LOG_MAXCAPA:
+		case HAK_OPT_LOG_MAXCAPA:
 			hak->option.log_maxcapa = *(hak_oow_t*)value;
 			break;
 
-		case HAK_LOG_TARGET_BCSTR:
+		case HAK_OPT_LOG_TARGET_BCSTR:
 		{
 			hak_bch_t* v1;
 			hak_uch_t* v2;
@@ -488,7 +566,7 @@ int hak_setoption (hak_t* hak, hak_option_t id, const void* value)
 			break;
 		}
 
-		case HAK_LOG_TARGET_UCSTR:
+		case HAK_OPT_LOG_TARGET_UCSTR:
 		{
 			hak_uch_t* v1;
 			hak_bch_t* v2;
@@ -508,7 +586,7 @@ int hak_setoption (hak_t* hak, hak_option_t id, const void* value)
 			break;
 		}
 
-		case HAK_LOG_TARGET_BCS:
+		case HAK_OPT_LOG_TARGET_BCS:
 		{
 			hak_bch_t* v1;
 			hak_uch_t* v2;
@@ -529,7 +607,7 @@ int hak_setoption (hak_t* hak, hak_option_t id, const void* value)
 			break;
 		}
 
-		case HAK_LOG_TARGET_UCS:
+		case HAK_OPT_LOG_TARGET_UCS:
 		{
 			hak_uch_t* v1;
 			hak_bch_t* v2;
@@ -550,7 +628,7 @@ int hak_setoption (hak_t* hak, hak_option_t id, const void* value)
 			break;
 		}
 
-		case HAK_SYMTAB_SIZE:
+		case HAK_OPT_SYMTAB_SIZE:
 		{
 			hak_oow_t w;
 
@@ -561,7 +639,7 @@ int hak_setoption (hak_t* hak, hak_option_t id, const void* value)
 			break;
 		}
 
-		case HAK_SYSDIC_SIZE:
+		case HAK_OPT_SYSDIC_SIZE:
 		{
 			hak_oow_t w;
 
@@ -572,7 +650,7 @@ int hak_setoption (hak_t* hak, hak_option_t id, const void* value)
 			break;
 		}
 
-		case HAK_PROCSTK_SIZE:
+		case HAK_OPT_PROCSTK_SIZE:
 		{
 			hak_oow_t w;
 
@@ -583,26 +661,63 @@ int hak_setoption (hak_t* hak, hak_option_t id, const void* value)
 			break;
 		}
 
-		case HAK_MOD_LIBDIRS:
+		case HAK_OPT_EXSTK_SIZE:
-		case HAK_MOD_PREFIX:
+		{
-		case HAK_MOD_POSTFIX:
+			hak_oow_t w;
+
+			w = *(hak_oow_t*)value;
+			if (w <= 0 || w > HAK_SMOOI_MAX) goto einval;
+
+			hak->option.dfl_exstk_size = *(hak_oow_t*)value;
+			break;
+		}
+
+		case HAK_OPT_CLSTK_SIZE:
+		{
+			hak_oow_t w;
+
+			w = *(hak_oow_t*)value;
+			if (w <= 0 || w > HAK_SMOOI_MAX) goto einval;
+
+			hak->option.dfl_clstk_size = *(hak_oow_t*)value;
+			break;
+		}
+
+		case HAK_OPT_MODLIBDIRS_BCSTR:
+			if (set_dual_str_opt(hak, value, 1, &hak->option.modlibdirs_b, &hak->option.modlibdirs_u) <= -1) return -1;
+			break;
+
+		case HAK_OPT_MODLIBDIRS_UCSTR:
+			if (set_dual_str_opt(hak, value, 0, &hak->option.modlibdirs_b, &hak->option.modlibdirs_u) <= -1) return -1;
+			break;
+
+		case HAK_OPT_MODPREFIX:
+		case HAK_OPT_MODPOSTFIX:
 		{
 			hak_oocs_t tmp;
 			int idx;
 
 			if (dup_str_opt(hak, (const hak_ooch_t*)value, &tmp) <= -1) return -1;
 
-			idx = id - HAK_MOD_LIBDIRS;
+			idx = id - HAK_OPT_MODPREFIX;
 			if (hak->option.mod[idx].ptr) hak_freemem(hak, hak->option.mod[idx].ptr);
 
 			hak->option.mod[idx] = tmp;
 			return 0;
 		}
 
-		case HAK_MOD_INCTX:
+		case HAK_OPT_MODINCTX:
 			hak->option.mod_inctx = *(void**)value;
 			break;
 
+		case HAK_OPT_INCDIRS_BCSTR:
+			if (set_dual_str_opt(hak, value, 1, &hak->option.incdirs_b, &hak->option.incdirs_u) <= -1) return -1;
+			break;
+
+		case HAK_OPT_INCDIRS_UCSTR:
+			if (set_dual_str_opt(hak, value, 0, &hak->option.incdirs_b, &hak->option.incdirs_u) <= -1) return -1;
+			break;
+
 		default:
 			goto einval;
 	}
@@ -623,57 +738,80 @@ int hak_getoption (hak_t* hak, hak_option_t id, void* value)
 {
 	switch  (id)
 	{
-		case HAK_TRAIT:
+		case HAK_OPT_TRAIT:
 			*(hak_bitmask_t*)value = hak->option.trait;
 			return 0;
 
-		case HAK_LOG_MASK:
+		case HAK_OPT_LOG_MASK:
 			*(hak_bitmask_t*)value = hak->option.log_mask;
 			return 0;
 
-		case HAK_LOG_MAXCAPA:
+		case HAK_OPT_LOG_MAXCAPA:
 			*(hak_oow_t*)value = hak->option.log_maxcapa;
 			return 0;
 
-		case HAK_LOG_TARGET_BCSTR:
+		case HAK_OPT_LOG_TARGET_BCSTR:
 			*(hak_bch_t**)value = hak->option.log_target_b;
 			return 0;
 
-		case HAK_LOG_TARGET_UCSTR:
+		case HAK_OPT_LOG_TARGET_UCSTR:
 			*(hak_uch_t**)value = hak->option.log_target_u;
 			return 0;
 
-		case HAK_LOG_TARGET_BCS:
+		case HAK_OPT_LOG_TARGET_BCS:
 			((hak_bcs_t*)value)->ptr = hak->option.log_target_b;
 			((hak_bcs_t*)value)->len = hak_count_bcstr(hak->option.log_target_b);
 			return 0;
 
-		case HAK_LOG_TARGET_UCS:
+		case HAK_OPT_LOG_TARGET_UCS:
 			((hak_ucs_t*)value)->ptr = hak->option.log_target_u;
 			((hak_ucs_t*)value)->len = hak_count_ucstr(hak->option.log_target_u);
 			return 0;
 
-		case HAK_SYMTAB_SIZE:
+		case HAK_OPT_SYMTAB_SIZE:
 			*(hak_oow_t*)value = hak->option.dfl_symtab_size;
 			return 0;
 
-		case HAK_SYSDIC_SIZE:
+		case HAK_OPT_SYSDIC_SIZE:
 			*(hak_oow_t*)value = hak->option.dfl_sysdic_size;
 			return 0;
 
-		case HAK_PROCSTK_SIZE:
+		case HAK_OPT_PROCSTK_SIZE:
 			*(hak_oow_t*)value = hak->option.dfl_procstk_size;
 			return 0;
 
-		case HAK_MOD_LIBDIRS:
+		case HAK_OPT_EXSTK_SIZE:
-		case HAK_MOD_PREFIX:
+			*(hak_oow_t*)value = hak->option.dfl_exstk_size;
-		case HAK_MOD_POSTFIX:
-			*(const hak_ooch_t**)value = hak->option.mod[id - HAK_MOD_LIBDIRS].ptr;
 			return 0;
 
-		case HAK_MOD_INCTX:
+		case HAK_OPT_CLSTK_SIZE:
+			*(hak_oow_t*)value = hak->option.dfl_clstk_size;
+			return 0;
+
+		case HAK_OPT_MODLIBDIRS_BCSTR:
+			*(const hak_bch_t**)value = hak->option.modlibdirs_b;
+			return 0;
+
+		case HAK_OPT_MODLIBDIRS_UCSTR:
+			*(const hak_uch_t**)value = hak->option.modlibdirs_u;
+			return 0;
+
+		case HAK_OPT_MODPREFIX:
+		case HAK_OPT_MODPOSTFIX:
+			*(const hak_ooch_t**)value = hak->option.mod[id - HAK_OPT_MODPREFIX].ptr;
+			return 0;
+
+		case HAK_OPT_MODINCTX:
 			*(void**)value = hak->option.mod_inctx;
 			return 0;
+
+		case HAK_OPT_INCDIRS_BCSTR:
+			*(const hak_bch_t**)value = hak->option.incdirs_b;
+			return 0;
+
+		case HAK_OPT_INCDIRS_UCSTR:
+			*(const hak_uch_t**)value = hak->option.incdirs_u;
+			return 0;
 	};
 
 	hak_seterrnum(hak, HAK_EINVAL);

lib/hak.h

@@ -241,33 +241,50 @@ typedef hak_errbinf_t hak_errinf_t;
 
 enum hak_option_t
 {
-	HAK_TRAIT,
+	HAK_OPT_TRAIT,
-	HAK_LOG_MASK,
+	HAK_OPT_LOG_MASK,
-	HAK_LOG_MAXCAPA,
+	HAK_OPT_LOG_MAXCAPA,
 
-	HAK_LOG_TARGET_BCSTR,
+	HAK_OPT_LOG_TARGET_BCSTR,
-	HAK_LOG_TARGET_UCSTR,
+	HAK_OPT_LOG_TARGET_UCSTR,
-	HAK_LOG_TARGET_BCS,
+	HAK_OPT_LOG_TARGET_BCS,
-	HAK_LOG_TARGET_UCS,
+	HAK_OPT_LOG_TARGET_UCS,
 #if defined(HAK_OOCH_IS_UCH)
-#	define HAK_LOG_TARGET HAK_LOG_TARGET_UCSTR
+#	define HAK_OPT_LOG_TARGET HAK_OPT_LOG_TARGET_UCSTR
-#	define HAK_LOG_TARGET_OOCSTR HAK_LOG_TARGET_UCSTR
+#	define HAK_OPT_LOG_TARGET_OOCSTR HAK_OPT_LOG_TARGET_UCSTR
-#	define HAK_LOG_TARGET_OOCS HAK_LOG_TARGET_UCS
+#	define HAK_OPT_LOG_TARGET_OOCS HAK_OPT_LOG_TARGET_UCS
 #else
-#	define HAK_LOG_TARGET HAK_LOG_TARGET_BCSTR
+#	define HAK_OPT_LOG_TARGET HAK_OPT_LOG_TARGET_BCSTR
-#	define HAK_LOG_TARGET_OOCSTR HAK_LOG_TARGET_BCSTR
+#	define HAK_OPT_LOG_TARGET_OOCSTR HAK_OPT_LOG_TARGET_BCSTR
-#	define HAK_LOG_TARGET_OOCS HAK_LOG_TARGET_BCS
+#	define HAK_OPT_LOG_TARGET_OOCS HAK_OPT_LOG_TARGET_BCS
 #endif
 
-	HAK_SYMTAB_SIZE,  /* default system table size */
+	HAK_OPT_SYMTAB_SIZE,  /* default system table size */
-	HAK_SYSDIC_SIZE,  /* default system dictionary size */
+	HAK_OPT_SYSDIC_SIZE,  /* default system dictionary size */
-	HAK_PROCSTK_SIZE, /* default process stack size */
+	HAK_OPT_PROCSTK_SIZE, /* default process stack size */
+	HAK_OPT_EXSTK_SIZE,   /* default exception stack size */
+	HAK_OPT_CLSTK_SIZE,   /* default class stack size */
 
-	HAK_MOD_LIBDIRS,
+	HAK_OPT_MODLIBDIRS_BCSTR,
-	HAK_MOD_PREFIX,
+	HAK_OPT_MODLIBDIRS_UCSTR,
-	HAK_MOD_POSTFIX,
+#if defined(HAK_OOCH_IS_UCH)
+#	define HAK_OPT_MODLIBDIRS HAK_OPT_MODLIBDIRS_UCSTR
+#else
+#	define HAK_OPT_MODLIBDIRS HAK_OPT_MODLIBDIRS_BCSTR
+#endif
 
-	HAK_MOD_INCTX
+	HAK_OPT_MODPREFIX,
+	HAK_OPT_MODPOSTFIX,
+
+	HAK_OPT_MODINCTX,
+
+	HAK_OPT_INCDIRS_BCSTR,
+	HAK_OPT_INCDIRS_UCSTR
+#if defined(HAK_OOCH_IS_UCH)
+#	define HAK_OPT_INCDIRS HAK_OPT_INCDIRS_UCSTR
+#else
+#	define HAK_OPT_INCDIRS HAK_OPT_INCDIRS_BCSTR
+#endif
 };
 typedef enum hak_option_t hak_option_t;
 
@@ -277,12 +294,28 @@ typedef enum hak_option_t hak_option_t;
 enum hak_option_dflval_t
 {
 	HAK_DFL_LOG_MAXCAPA = HAK_LOG_CAPA_ALIGN * 16,
-	HAK_DFL_SYMTAB_SIZE = 5000,
+
-	HAK_DFL_SYSDIC_SIZE = 5000,
+#if defined(HAK_SMALL_MEMORY_FOOTPRINT)
-	HAK_DFL_PROCSTK_SIZE = 5000
+	HAK_DFL_SYMTAB_SIZE  = 1024,
+	HAK_DFL_SYSDIC_SIZE  = 1024
+	HAK_DFL_PROCSTK_SIZE = 1024,   /* -> fstk 1024, the FSTK floor */
+	HAK_DFL_EXSTK_SIZE   = 256,    /* 4 slots/level x 59 levels = 236 */
+	HAK_DFL_CLSTK_SIZE   = 16,     /* = HAK_MIN_CLSTK_SIZE */
+#else
+	HAK_DFL_SYMTAB_SIZE  = 8192,
+	HAK_DFL_SYSDIC_SIZE  = 8192,
+	HAK_DFL_PROCSTK_SIZE = 8192,
+	HAK_DFL_EXSTK_SIZE   = 2048,
+	HAK_DFL_CLSTK_SIZE   = 64
+#endif
 };
 typedef enum hak_option_dflval_t hak_option_dflval_t;
 
+#define HAK_MIN_PROCSTK_SIZE (192)
+#define HAK_MIN_EXSTK_SIZE   (32) /* 4 slots/try  -> 8 nested trys */
+#define HAK_MIN_CLSTK_SIZE   (16) /* 1 slot/class -> 16 nested classes */
+#define HAK_MIN_FSTK_SIZE    (1024)
+
 enum hak_trait_t
 {
 #if defined(HAK_BUILD_DEBUG)
@@ -690,7 +723,7 @@ struct hak_block_t
 /* the fields of hak_context_t must be mirroed to hak_stack_context_t
  * in hak-prv.h. there are functions affected by the layout change
  * of these structures:
- * - hak_reify_stack_context() in lib/exec.
+ * - hak_reifystackcontext() in lib/exec.
  * - make_stack_context() in lib/exec.c
  */
 struct hak_context_t
@@ -793,6 +826,8 @@ struct hak_process_t
 	hak_oop_t         clsp; /* class stack pointer */
 	hak_oop_t         clst; /* class stack  top */
 
+	/* frame stack store the context objects when the stack context feature is enabled.
+	 * if both fsp and fst are to clst, the stack context feature is disabled */
 	hak_oop_t         fsp;  /* frame stack pointer */
 	hak_oop_t         fst;  /* frame stack top */
 
@@ -1764,9 +1799,22 @@ struct hak_t
 		hak_oow_t dfl_symtab_size;
 		hak_oow_t dfl_sysdic_size;
 		hak_oow_t dfl_procstk_size;
+		hak_oow_t dfl_exstk_size;
+		hak_oow_t dfl_clstk_size;
 		void* mod_inctx;
 
-		hak_oocs_t mod[3];
+		/* both representations are kept for the two options whose consumers
+		 * are byte oriented: dl_open() feeds dlopen() and open_cci_stream()
+		 * feeds fopen(), so the bch form is what actually gets used, while the
+		 * uch form serves getoption and %js. converting once at set time beats
+		 * converting on every module load and every include attempt. */
+		hak_bch_t* modlibdirs_b;
+		hak_uch_t* modlibdirs_u;
+		hak_bch_t* incdirs_b;
+		hak_uch_t* incdirs_u;
+
+		/* prefix and postfix only - indexed by (id - HAK_OPT_MODPREFIX) */
+		hak_oocs_t mod[2];
 
 	#if defined(HAK_BUILD_DEBUG)
 		/* set automatically when trait is set */
@@ -1921,11 +1969,11 @@ struct hak_t
 	hak_oob_t* active_code;
 	hak_ooi_t sp;
 	hak_ooi_t ip;
-	hak_uint8_t abort_req;
+	volatile hak_int8_t abort_req;
 	hak_uint8_t no_proc_switch; /* process switching disabled */
 	hak_uint8_t proc_switched; /* TODO: this is temporary. implement something else to skip immediate context switching */
 	hak_uint8_t rcv_tick; /* whether to receive tick or not */
-	hak_uint32_t tick; /* instance specific tick */
+	volatile hak_uint32_t tick; /* instance specific tick */
 	hak_uint32_t last_tick;  /* last instance specific tick this instance acted on */
 	hak_uint32_t last_gtick;  /* last global tick this instance acted on */
 
@@ -3549,7 +3597,11 @@ HAK_EXPORT void hak_assertfailed (
 /* =========================================================================
  * HELPERS
  * ========================================================================= */
-HAK_EXPORT void hak_start_ticker (
+/**
+ * The hak_start_ticker() starts the ticker for process switching.
+ * It returns 1 on success, 0 if already started, -1 upon failure.
+ */
+HAK_EXPORT int hak_start_ticker (
 	void
 );
 

lib/json.c

@@ -952,7 +952,7 @@ hak_json_t* hak_json_open (hak_mmgr_t* mmgr, hak_oow_t xtnsize, hak_json_prim_t*
 	/* the dummy hak is used for this json to perform primitive operations
 	 * such as getting system time or logging. so the heap size doesn't
 	 * need to be changed from the tiny value set above. */
-	hak_setoption(json->dummy_hak, HAK_LOG_MASK, &json->cfg.logmask);
+	hak_setoption(json->dummy_hak, HAK_OPT_LOG_MASK, &json->cfg.logmask);
 	hak_setcmgr(json->dummy_hak, json->cmgr);
 
 
@@ -987,7 +987,7 @@ int hak_json_setoption (hak_json_t* json, hak_json_option_t id, const void* valu
 				 * existing hak instances inside worker threads won't get
 				 * affected. new hak instances to be created later
 				 * is supposed to use the new value */
-				hak_setoption(json->dummy_hak, HAK_LOG_MASK, value);
+				hak_setoption(json->dummy_hak, HAK_OPT_LOG_MASK, value);
 			}
 			return 0;
 	}

lib/obj.c

@@ -470,6 +470,10 @@ hak_oop_t hak_makestringwithuchars (hak_t* hak, const hak_uch_t* ptr, hak_oow_t
 
 hak_oop_t hak_makestringwithbchars (hak_t* hak, const hak_bch_t* ptr, hak_oow_t len)
 {
+#if defined(HAK_OOCH_IS_UCH)
+	hak_oow_t xlen;
+	hak_ooch_t* xptr;
+#endif
 	/* you must provide the payload when calling this variant. it can't figure out
 	 * the actual number of hak_ooch_t characters */
 	if (!ptr)
@@ -480,9 +484,6 @@ hak_oop_t hak_makestringwithbchars (hak_t* hak, const hak_bch_t* ptr, hak_oow_t
 	}
 
 #if defined(HAK_OOCH_IS_UCH)
-	hak_oow_t xlen;
-	hak_ooch_t* xptr;
-
 	xptr = hak_dupbtooochars(hak, ptr, len, &xlen);
 	if (HAK_UNLIKELY(!xptr))
 	{

lib/prim.c

@@ -1220,7 +1220,7 @@ static hak_pfrc_t pf_va_get (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 }
 
 
-static hak_pfrc_t pf_object_new (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
+hak_pfrc_t hak_pf_object_new (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 {
 	hak_oop_t obj;
 	hak_oop_t _class;
@@ -1256,7 +1256,7 @@ static hak_pfrc_t pf_object_new (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 
 /* ------------------------------------------------------------------------- */
 
-static hak_pfrc_t pf_system_get_sigfd (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
+hak_pfrc_t hak_pf_system_get_sigfd (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 {
 	hak_ooi_t fd;
 	hak_hnd_t* hnd;
@@ -1264,7 +1264,7 @@ static hak_pfrc_t pf_system_get_sigfd (hak_t* hak, hak_mod_t* mod, hak_ooi_t nar
 	fd = hak->vmprim.vm_getsigfd(hak);
 
 	/* hand back a system handle id rather than the descriptor itself, so that
-	 * the result can be given to sem-signal-on-input - which resolves handle
+	 * the result can be given to core.sem-signal-on-input - which resolves handle
 	 * ids, not descriptors. wrapped HAK_HND_OPEN_KEEPOPEN because the VM owns
 	 * this descriptor and manages its blocking mode; the table must never
 	 * close it. wrapfd_once() keeps the id stable across calls. */
@@ -1275,7 +1275,7 @@ static hak_pfrc_t pf_system_get_sigfd (hak_t* hak, hak_mod_t* mod, hak_ooi_t nar
 	return HAK_PF_SUCCESS;
 }
 
-static hak_pfrc_t pf_system_get_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
+hak_pfrc_t hak_pf_system_get_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 {
 	hak_uint8_t sig;
 	int n;
@@ -1289,12 +1289,12 @@ static hak_pfrc_t pf_system_get_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs
 	return HAK_PF_SUCCESS;
 }
 
-/* (system-catch-sig signo)   - route an operating system signal into the
+/* (sys.sig-catch signo)   - route an operating system signal into the signal
- *                              signal descriptor, where hak code can wait for
+ *                           descriptor, where hak code can wait for it with
- *                              it with sem-signal-on-input
+ *                           core.sem-signal-on-input
- * (system-uncatch-sig signo) - release it again
+ * (sys.sig-uncatch signo) - release it again
  *
- * Note the difference from system-set-sig, which does not touch the operating
+ * Note the difference from sys.sig-set, which does not touch the operating
  * system at all: that one injects a number into the descriptor directly, as a
  * way for hak code to post a synthetic signal to itself.
  */
@@ -1323,17 +1323,17 @@ static hak_pfrc_t __system_catch_sig (hak_t* hak, hak_ooi_t nargs, int enable)
 	return HAK_PF_SUCCESS;
 }
 
-static hak_pfrc_t pf_system_catch_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
+hak_pfrc_t hak_pf_system_catch_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 {
 	return __system_catch_sig(hak, nargs, 1);
 }
 
-static hak_pfrc_t pf_system_uncatch_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
+hak_pfrc_t hak_pf_system_uncatch_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 {
 	return __system_catch_sig(hak, nargs, 0);
 }
 
-static hak_pfrc_t pf_system_set_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
+hak_pfrc_t hak_pf_system_set_sig (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
 {
 	hak_oop_t tmp;
 	hak_uint8_t sig;
@@ -1366,11 +1366,10 @@ static pf_t builtin_prims[] =
 	{ 1, HAK_TYPE_MAX(hak_oow_t), pf_scanf,           5,  { 's','c','a','n','f' } },
 	{ 1, HAK_TYPE_MAX(hak_oow_t), pf_sprintf,         7,  { 's','p','r','i','n','t','f' } },
 
-	{ 0, 0,                       pf_system_get_sigfd,   16, { 's','y','s','t','e','m','-','g','e','t','-','s','i','g','f','d' } },
+	/* the signal primitives are registered by the sys module instead - see
-	{ 0, 0,                       pf_system_get_sig,     14,  { 's','y','s','t','e','m','-','g','e','t','-','s','i','g' } },
+	 * pfinfos[] in mod/sys.c. they are reached as sys.sig-getfd, sys.sig-get,
-	{ 1, 1,                       pf_system_set_sig,     14,  { 's','y','s','t','e','m','-','s','e','t','-','s','i','g' } },
+	 * sys.sig-set, sys.sig-catch and sys.sig-uncatch. the implementations stay
-	{ 1, 1,                       pf_system_catch_sig,   16, { 's','y','s','t','e','m','-','c','a','t','c','h','-','s','i','g' } },
+	 * here and are declared in lib/hak-prv.h. */
-	{ 1, 1,                       pf_system_uncatch_sig, 18, { 's','y','s','t','e','m','-','u','n','c','a','t','c','h','-','s','i','g' } },
 
 	{ 0, 0,                       pf_gc,              2,  { 'g','c' } },
 
@@ -1435,30 +1434,7 @@ static pf_t builtin_prims[] =
 
 	{ 0, 0,                       pf_va_context,      10, { 'v','a','-','c','o','n','t','e','x','t' } },
 	{ 0, 1,                       pf_va_count,        8,  { 'v','a','-','c','o','u','n','t' } },
-	{ 1, 2,                       pf_va_get,          6,  { 'v','a','-','g','e','t' } },
+	{ 1, 2,                       pf_va_get,          6,  { 'v','a','-','g','e','t' } }
-
-	{ 1, 2,                       pf_object_new,                           10, { 'o','b','j','e','c','t','-','n','e','w' } },
-
-	{ 0, 0,                       hak_pf_process_current,                  15, { 'c','u','r','r','e','n','t','-','p','r','o','c','e','s','s'} },
-	{ 1, HAK_TYPE_MAX(hak_oow_t), hak_pf_process_fork,                      4, { 'f','o','r','k'} },
-	{ 1, 1,                       hak_pf_process_resume,                    6, { 'r','e','s','u','m','e' } },
-	{ 0, 1,                       hak_pf_process_suspend,                   7, { 's','u','s','p','e','n','d' } },
-	{ 0, 1,                       hak_pf_process_terminate,                 9, { 't','e','r','m','i','n','a','t','e' } },
-	{ 0, 0,                       hak_pf_process_terminate_all,            13, { 't','e','r','m','i','n','a','t','e','-','a','l','l' } },
-	{ 0, 0,                       hak_pf_process_yield,                     5, { 'y','i','e','l','d'} },
-
-
-	{ 0, 0,                       hak_pf_semaphore_new,                     7, { 's','e','m','-','n','e','w'} },
-	{ 1, 1,                       hak_pf_semaphore_wait,                    8, { 's','e','m','-','w','a','i','t'} },
-	{ 1, 3,                       hak_pf_semaphore_signal,                 10, { 's','e','m','-','s','i','g','n','a','l'} },
-	{ 2, 2,                       hak_pf_semaphore_signal_on_input,        19, { 's','e','m','-','s','i','g','n','a','l','-','o','n','-','i','n','p','u','t'} },
-	{ 2, 2,                       hak_pf_semaphore_signal_on_output,       20, { 's','e','m','-','s','i','g','n','a','l','-','o','n','-','o','u','t','p','u','t'} },
-	{ 1, 1,                       hak_pf_semaphore_unsignal,               12, { 's','e','m','-','u','n','s','i','g','n','a','l'} },
-
-	{ 0, 0,                       hak_pf_semaphore_group_new,               9, { 's','e','m','g','r','-','n','e','w'} },
-	{ 1, 2,                       hak_pf_semaphore_group_add_semaphore,     9, { 's','e','m','g','r','-','a','d','d'} },
-	{ 1, 2,                       hak_pf_semaphore_group_remove_semaphore, 12, { 's','e','m','g','r','-','r','e','m','o','v','e'} },
-	{ 1, 1,                       hak_pf_semaphore_group_wait,             10, { 's','e','m','g','r','-','w','a','i','t'} }
 };
 
 int hak_addbuiltinprims (hak_t* hak)

lib/read.c

@@ -35,12 +35,13 @@
 static struct voca_t
 {
 	hak_oow_t len;
-	hak_ooch_t str[11];
+	hak_ooch_t str[15];
 } vocas[] =
 {
 /* TODO: change $include and $pragma to #\include or #\pragma or use some other prefix like #^ -> $ to use really for variable reference or something...
  * TODO: change #\ to something else... */
 	{  8, { '$','i','n','c','l','u','d','e'                               } },
+	{ 13, { '$','i','n','c','l','u','d','e','-','o','n','c','e'           } },
 	{  7, { '$','p','r','a','g','m','a'                                   } },
 
 	{ 11, { '#','\\','b','a','c','k','s','p','a','c','e'                  } },
@@ -110,6 +111,7 @@ static struct voca_t
 enum voca_id_t
 {
 	VOCA_INCLUDE,
+	VOCA_INCLUDE_ONCE,
 	VOCA_PRAGMA,
 
 	VOCA_CHAR_BACKSPACE,
@@ -300,7 +302,7 @@ static HAK_INLINE int is_delim_char (hak_ooci_t c)
 	return c == '(' || c == ')' || c == '[' || c == ']' || c == '{' || c == '}' ||
 	       c == '|' || c == ',' || c == '.' || c == ':' || c == ';' ||
 	       /* the first characters of tokens in delim_token_tab up to this point */
-#if defined(HAK_OOCH_IS_UCH) && defined(HAK_LANG_ENABLE_WIDE_DELIM)
+#if defined(HAK_OOCH_IS_UCH) && defined(HAK_LANG_ENABLE_WIDE_DELIM) && defined(HAVE_ESCAPE_U)
 	       c == L'\u201C' || c == L'\u201D' ||  /* “ ” */
 	       c == L'\u2018' || c == L'\u2019' ||  /* ‘ ’ */
 #endif
@@ -400,6 +402,11 @@ static int get_directive_token_type (hak_t* hak, hak_tok_type_t* tok_type)
 		*tok_type = HAK_TOK_INCLUDE;
 		return 0;
 	}
+	else if (does_token_name_match(hak, VOCA_INCLUDE_ONCE))
+	{
+		*tok_type = HAK_TOK_INCLUDE_ONCE;
+		return 0;
+	}
 	else if (does_token_name_match(hak, VOCA_PRAGMA))
 	{
 		*tok_type = HAK_TOK_PRAGMA;
@@ -1440,11 +1447,12 @@ static void init_feed (hak_t* hak)
 
 /* ------------------------------------------------------------------------ */
 
-static int feed_begin_include (hak_t* hak)
+static int feed_begin_include (hak_t* hak, int once)
 {
 	hak_io_cciarg_t* arg;
 	const hak_ooch_t* io_name;
 
+/* TODO: handle once... */
 	io_name = add_sr_name(hak, TOKEN_NAME(hak));
 	if (HAK_UNLIKELY(!io_name))
 	{
@@ -1761,12 +1769,12 @@ static int feed_process_token (hak_t* hak)
 			goto oops;
 		}
 
-		frd->expect_include_file = 0;
 
 		/* indicate that the file inclusion should be performed soon.
 		 * don't perform actual inclusion here so that the return value of
 		 * feed_char() advances the input pointers properly. */
-		frd->do_include_file = 1;
+		frd->do_include_file = frd->expect_include_file;
+		frd->expect_include_file = 0;
 
 		goto ok;
 	}
@@ -1807,6 +1815,10 @@ static int feed_process_token (hak_t* hak)
 			frd->expect_include_file = 1;
 			goto ok;
 
+		case HAK_TOK_INCLUDE_ONCE:
+			frd->expect_include_file = 2;
+			goto ok;
+
 		case HAK_TOK_PRAGMA:
 /* TODO: check if pragma is the first word in the line */
 			frd->expect_pragma_item = 1;
@@ -2665,7 +2677,7 @@ static int flx_start (hak_t* hak, hak_ooci_t c)
 			FEED_CONTINUE(hak, HAK_FLX_QUOTED_TOKEN); /* discard the quote itself. move on the the QUOTED_TOKEN state */
 			goto consumed;
 
-#if defined(HAK_OOCH_IS_UCH) && defined(HAK_LANG_ENABLE_WIDE_DELIM)
+#if defined(HAK_OOCH_IS_UCH) && defined(HAK_LANG_ENABLE_WIDE_DELIM) && defined(HAVE_ESCAPE_U)
 		case L'\u201C': /* “ ” */
 			init_flx_qt(FLX_QT(hak), HAK_TOK_STRLIT, HAK_SYNERR_STRLIT, L'\u201D', '\\', 0, HAK_TYPE_MAX(hak_oow_t), 0);
 			FEED_CONTINUE(hak, HAK_FLX_QUOTED_TOKEN); /* discard the quote itself. move on the the QUOTED_TOKEN state */
@@ -3916,8 +3928,9 @@ static int feed_from_includee (hak_t* hak)
 			 * directive, sets hak->c->feed.rd.do_include_file to 1 instead of attepmting
 			 * to include the file. the file inclusion is attempted here after the return
 			 * value of feed_char() is used to advance the hak->c->curinp->b.pos pointer. */
+			int incmod = hak->c->feed.rd.do_include_file;
 			hak->c->feed.rd.do_include_file = 0; /* clear this regardless of inclusion result */
-			if (feed_begin_include(hak) <= -1) goto oops;
+			if (feed_begin_include(hak, incmod == 2) <= -1) goto oops;
 			curinp = hak->c->curinp;
 		}
 	}
@@ -4012,8 +4025,9 @@ int hak_feed (hak_t* hak, const hak_ooch_t* data, hak_oow_t len)
 
 			if (hak->c->feed.rd.do_include_file)
 			{
+				int incmod = hak->c->feed.rd.do_include_file;
 				hak->c->feed.rd.do_include_file = 0; /* done regardless of inclusion result */
-				if (feed_begin_include(hak) <= -1) goto oops;
+				if (feed_begin_include(hak, incmod == 2) <= -1) goto oops;
 			}
 
 			if (hak->c->curinp && hak->c->curinp != &hak->c->cci_arg && feed_from_includee(hak) <= -1)

lib/std.c

@@ -38,6 +38,15 @@
 #	define USE_THREAD
 #endif
 
+/* BeOS and Haiku accept ITIMER_VIRTUAL, count it down, and never raise
+ * SIGVTALRM. setitimer() reports success, so the -1 fallback in start_ticker()
+ * cannot catch it and the wall-clock timer has to be chosen up front. Stated
+ * in the negative so an unknown platform keeps preferring the cpu-time timer,
+ * which is what every other system here implements correctly. */
+#if defined(__BEOS__) || defined(__HAIKU__)
+#	define ITIMER_VIRTUAL_NOT_WORKING
+#endif
+
 #if defined(__BORLANDC__) && defined(__DOS__)  && defined(_WIN32) && defined(__DPMI32__)
 /* bcc32 with powerpack seems to define _WIN32 in DPMI32 mode */
 #	undef _WIN32
@@ -212,7 +221,26 @@
 #		include <sched.h>
 #	endif
 
-#	if defined(HAVE_SYS_DEVPOLL_H)
+	/* define FORCE_USE_SELECT or FORCE_USE_POLL to test those backends on a
+	 * platform that would otherwise pick a better multiplexer. they must come
+	 * first in this chain so the auto-detection below is skipped entirely -
+	 * otherwise USE_EPOLL and USE_SELECT both end up defined and the XPOLLXXX
+	 * values get redefined. */
+#	if defined(FORCE_USE_POLL)
+#		include <poll.h>
+#		define USE_POLL
+#		define XPOLLIN POLLIN
+#		define XPOLLOUT POLLOUT
+#		define XPOLLERR POLLERR
+#		define XPOLLHUP POLLHUP
+#	elif defined(FORCE_USE_SELECT)
+#		define USE_SELECT
+		/* fake XPOLLXXX values */
+#		define XPOLLIN  (1 << 0)
+#		define XPOLLOUT (1 << 1)
+#		define XPOLLERR (1 << 2)
+#		define XPOLLHUP (1 << 3)
+#	elif defined(HAVE_SYS_DEVPOLL_H)
 		/* solaris */
 #		include <sys/devpoll.h>
 #		define USE_DEVPOLL
@@ -328,7 +356,7 @@
  * about async-signal-safety - the spinlock is built out of atomics and is safe
  * by that measure - but about reentrancy: a signal delivered to the thread
  * that already holds the lock would spin, or block, on a lock that thread can
- * no longer reach the end of. post_sig_to_all_haks() therefore walk the chain without it.
+ * no longer reach the end of. post_sig_to_all_haks() therefore walks the chain without it.
  * -------------------------------------------------------------------------- */
 
 #if defined(USE_THREAD)
@@ -448,6 +476,11 @@ struct xtn_t
 			struct pollfd* ptr;
 			hak_oow_t capa;
 			hak_oow_t len;
+			/* bumped on every add and delete. poll() works on a copy of ptr[]
+			 * taken before it blocks, so a descriptor unregistered during the
+			 * call cannot be withdrawn from it. this lets the io thread notice
+			 * that the set changed underneath a wait and discard its results. */
+			hak_oow_t epoch;
 		#if defined(USE_THREAD)
 			pthread_mutex_t pmtx;
 		#endif
@@ -460,6 +493,10 @@ struct xtn_t
 			fd_set rfds;
 			fd_set wfds;
 			int maxfd;
+			/* see the epoch field in the USE_POLL registry above - select()
+			 * works on a copy of rfds/wfds in the same way and needs the
+			 * same protection against a descriptor unregistered mid-call. */
+			hak_oow_t epoch;
 		#if defined(USE_THREAD)
 			pthread_mutex_t smtx;
 		#endif
@@ -1510,6 +1547,32 @@ static void vm_gettime (hak_t* hak, hak_ntime_t* now)
  * IO MULTIPLEXING
  * ----------------------------------------------------------------- */
 
+#if defined(USE_THREAD) && (defined(USE_POLL) || defined(USE_SELECT))
+/* Kick the io thread out of poll()/select().
+ *
+ * these two backends wait on a snapshot of the registry, so a descriptor
+ * registered or unregistered by the vm while the thread is blocked does not
+ * take effect until the current wait expires - up to the 10 second timeout in
+ * iothr_main(). The vm would sit there waiting for input on a descriptor the
+ * multiplexer is not even watching yet. The kernel-object backends (devpoll,
+ * kqueue, epoll) need none of this because the registration itself lands in
+ * the object the thread is blocked on.
+ *
+ * iothr.p[0] is registered for input, so one byte here makes the wait return
+ * at once and the next round re-snapshots. Anything other than 'Q' is drained
+ * and ignored by the dispatch loop in vm_muxwait().
+ *
+ * called from the vm thread with no registry lock held: the pipe is
+ * non-blocking, and a full pipe (EAGAIN) already means a wake is pending. */
+static void wake_iothr (hak_t* hak)
+{
+	xtn_t* xtn = GET_XTN(hak);
+	if (xtn->iothr.up && !xtn->iothr.abort) write(xtn->iothr.p[1], "W", 1);
+}
+#else
+#	define wake_iothr(hak) ((void)0)
+#endif
+
 static int _add_poll_fd (hak_t* hak, int fd, int event_mask)
 {
 #if defined(USE_DEVPOLL)
@@ -1666,8 +1729,10 @@ static int _add_poll_fd (hak_t* hak, int fd, int event_mask)
 	xtn->ev.reg.ptr[xtn->ev.reg.len].events = event_mask;
 	xtn->ev.reg.ptr[xtn->ev.reg.len].revents = 0;
 	xtn->ev.reg.len++;
+	xtn->ev.reg.epoch++;
 	MUTEX_UNLOCK(&xtn->ev.reg.pmtx);
 
+	wake_iothr(hak);
 	return 0;
 
 #elif defined(USE_SELECT)
@@ -1684,8 +1749,10 @@ static int _add_poll_fd (hak_t* hak, int fd, int event_mask)
 		FD_SET (fd, &xtn->ev.reg.wfds);
 		if (fd > xtn->ev.reg.maxfd) xtn->ev.reg.maxfd = fd;
 	}
+	xtn->ev.reg.epoch++;
 	MUTEX_UNLOCK(&xtn->ev.reg.smtx);
 
+	wake_iothr(hak);
 	return 0;
 
 #else
@@ -1785,7 +1852,15 @@ static int _del_poll_fd (hak_t* hak, int fd)
 		{
 			xtn->ev.reg.len--;
 			HAK_MEMMOVE(&xtn->ev.reg.ptr[i], &xtn->ev.reg.ptr[i+1], (xtn->ev.reg.len - i) * HAK_SIZEOF(*xtn->ev.reg.ptr));
+			xtn->ev.reg.epoch++;
 			MUTEX_UNLOCK(&xtn->ev.reg.pmtx);
+
+			/* wake on delete too, not just on add. the epoch bump above
+			 * already stops a stale result from being dispatched, but until
+			 * the thread re-snapshots it keeps waiting on a descriptor the vm
+			 * has dropped - and the pending epoch mismatch discards the next
+			 * batch whole, however genuine the rest of it is. */
+			wake_iothr(hak);
 			return 0;
 		}
 	}
@@ -1811,8 +1886,10 @@ static int _del_poll_fd (hak_t* hak, int fd)
 		}
 		xtn->ev.reg.maxfd = i;
 	}
+	xtn->ev.reg.epoch++;
 	MUTEX_UNLOCK(&xtn->ev.reg.smtx);
 
+	wake_iothr(hak);
 	return 0;
 
 #else
@@ -1839,7 +1916,7 @@ static int _mod_poll_fd (hak_t* hak, int fd, int event_mask)
 #elif defined(USE_KQUEUE)
 	xtn_t* xtn = GET_XTN(hak);
 	hak_oow_t rindex, roffset;
-	int rv, newrv = 0;
+	int rv, newrv;
 	struct kevent ev;
 
 	rindex = (hak_oow_t)fd / (HAK_BITSOF(hak_oow_t) >> 1);
@@ -1853,6 +1930,7 @@ static int _mod_poll_fd (hak_t* hak, int fd, int event_mask)
 	};
 
 	rv = HAK_GETBITS(hak_oow_t, xtn->ev.reg.ptr[rindex], roffset, 2);
+	newrv = rv; /* start from what is registered; each branch below applies its own diff */
 
 	if (rv & 1)
 	{
@@ -1960,12 +2038,18 @@ kqueue_syserr:
 	{
 		if (xtn->ev.reg.ptr[i].fd == fd)
 		{
-			HAK_MEMMOVE(&xtn->ev.reg.ptr[i], &xtn->ev.reg.ptr[i+1], (xtn->ev.reg.len - i - 1) * HAK_SIZEOF(*xtn->ev.reg.ptr));
+			/* modify in place. shifting the tail down the way a delete does
-			xtn->ev.reg.ptr[i].fd = fd;
+			 * would drop the entry at i+1 - it lands on i and is overwritten
+			 * right after - and leave a stale duplicate in the last slot,
+			 * since len does not change. */
 			xtn->ev.reg.ptr[i].events = event_mask;
 			xtn->ev.reg.ptr[i].revents = 0;
+			/* the direction changed, so a result computed from the old mask
+			 * must not be dispatched. see the epoch check in iothr_main(). */
+			xtn->ev.reg.epoch++;
 			MUTEX_UNLOCK(&xtn->ev.reg.pmtx);
 
+			wake_iothr(hak);
 			return 0;
 		}
 	}
@@ -1992,7 +2076,10 @@ kqueue_syserr:
 	else
 		FD_CLR(fd, &xtn->ev.reg.wfds);
 
+	xtn->ev.reg.epoch++;
 	MUTEX_UNLOCK(&xtn->ev.reg.smtx);
+
+	wake_iothr(hak);
 	return 0;
 
 #else
@@ -2003,6 +2090,24 @@ kqueue_syserr:
 }
 
 #if defined(USE_THREAD)
+
+#if defined(USE_KQUEUE)
+	/* kqueue reports one filter per event rather than a mask, so it has no
+	 * MUXEVT_MASK - the entry is kept or dropped whole. */
+#	define MUXEVT_FD(e)   ((int)(e).ident)
+#elif defined(USE_DEVPOLL) || defined(USE_POLL)
+#	define MUXEVT_FD(e)   ((e).fd)
+#	define MUXEVT_MASK(e) ((e).revents)
+#elif defined(USE_EPOLL)
+#	define MUXEVT_FD(e)   ((e).data.fd)
+#	define MUXEVT_MASK(e) ((e).events)
+#elif defined(USE_SELECT)
+#	define MUXEVT_FD(e)   ((e).fd)
+#	define MUXEVT_MASK(e) ((e).events)
+#else
+#	error UNSUPPORTED
+#endif
+
 /* Drop multiplexer events already sitting in the buffer for this descriptor.
  *
  * iothr_main() reads events straight into xtn->ev.buf and publishes ev.len;
@@ -2018,22 +2123,36 @@ kqueue_syserr:
  * caches ev.len and would walk entries this function compacts away. Nothing
  * does today - signalling a semaphore only makes a process runnable, it does
  * not run hak code - but the loop has no defence if that ever changes. */
-static void purge_muxevts (hak_t* hak, int fd)
+static void purge_muxevts (hak_t* hak, int fd, int keep_mask)
 {
 	xtn_t* xtn = GET_XTN(hak);
 	hak_oow_t i, j;
+#if defined(USE_KQUEUE)
+	int dir_mask;
+#else
+	int drop = (XPOLLIN | XPOLLOUT) & ~keep_mask;
+#endif
 
 	MUTEX_LOCK(&xtn->ev.mtx);
 
 	for (i = 0, j = 0; i < xtn->ev.len; i++)
 	{
-	#if defined(USE_DEVPOLL) || defined(USE_POLL) || defined(USE_SELECT)
+		if (MUXEVT_FD(xtn->ev.buf[i]) == fd)
-		if (xtn->ev.buf[i].fd == fd) continue;
+		{
-	#elif defined(USE_KQUEUE)
+			if (!keep_mask) continue; /* nothing registered survives */
-		if ((int)xtn->ev.buf[i].ident == fd) continue;
+		#if defined(USE_KQUEUE)
-	#elif defined(USE_EPOLL)
+			dir_mask = 0;
-		if (xtn->ev.buf[i].data.fd == fd) continue;
+			/* it's "if .. else if" because kqueue filter is either READ or WRITE.
+			 * the flags field which can set with EV_EOF or EV_ERROR is not used here */
+			if (xtn->ev.buf[i].filter == EVFILT_READ) dir_mask |= XPOLLIN;
+			else if (xtn->ev.buf[i].filter == EVFILT_WRITE) dir_mask |= XPOLLOUT;
+			if (!(dir_mask & keep_mask)) continue;
+		#else
+			MUXEVT_MASK(xtn->ev.buf[i]) &= ~drop;
+			if (!(MUXEVT_MASK(xtn->ev.buf[i]) & (XPOLLIN | XPOLLOUT | XPOLLERR | XPOLLHUP))) continue;
 		#endif
+		}
+
 		if (j != i) xtn->ev.buf[j] = xtn->ev.buf[i];
 		j++;
 	}
@@ -2069,6 +2188,7 @@ static int vm_muxadd (hak_t* hak, hak_ooi_t io_handle, hak_ooi_t mask)
 static int vm_muxmod (hak_t* hak, hak_ooi_t io_handle, hak_ooi_t mask)
 {
 	int event_mask;
+	int n;
 
 	event_mask = 0;
 	if (mask & HAK_SEMAPHORE_IO_MASK_INPUT) event_mask |= XPOLLIN;
@@ -2081,16 +2201,13 @@ static int vm_muxmod (hak_t* hak, hak_ooi_t io_handle, hak_ooi_t mask)
 		return -1;
 	}
 
-	return _mod_poll_fd(hak, io_handle, event_mask);
+	n = _mod_poll_fd(hak, io_handle, event_mask);
 
-	/* [NOTE]
+#if defined(USE_THREAD)
-	 *   this may need the same mux event purge as vm_muxdel() for accuracy.
+	purge_muxevts(hak, (int)io_handle, event_mask);
-	 *   if a file descriptor is removed for one direction while another direction
+#endif
-	 *   is still watched, this function is invoked. in that case, xtn->evt.buf
+
-	 *   may have some stale events and they can raise spurious signals.
+	return n;
-	 *
-	 *   TODO: per-direction event purge
-	 */
 }
 
 static int vm_muxdel (hak_t* hak, hak_ooi_t io_handle)
@@ -2105,7 +2222,7 @@ static int vm_muxdel (hak_t* hak, hak_ooi_t io_handle)
 	 * delete does not make a buffered event any less stale.
 	 * delete_sem_from_sem_io_tuple() carries on regardless when force is set.
 	 */
-	purge_muxevts(hak, (int)io_handle);
+	purge_muxevts(hak, (int)io_handle, 0);
 #endif
 	return n;
 }
@@ -2128,11 +2245,13 @@ static void* iothr_main (void* arg)
 			struct timespec ts;
 		#elif defined(USE_POLL)
 			hak_oow_t nfds;
+			hak_oow_t epoch;
 		#elif defined(USE_SELECT)
 			struct timeval tv;
 			fd_set rfds;
 			fd_set wfds;
 			int maxfd;
+			hak_oow_t epoch;
 		#endif
 
 		poll_for_event:
@@ -2154,8 +2273,23 @@ static void* iothr_main (void* arg)
 			MUTEX_LOCK(&xtn->ev.reg.pmtx);
 			HAK_MEMCPY(xtn->ev.buf, xtn->ev.reg.ptr, xtn->ev.reg.len * HAK_SIZEOF(*xtn->ev.buf));
 			nfds = xtn->ev.reg.len;
+			epoch = xtn->ev.reg.epoch;
 			MUTEX_UNLOCK(&xtn->ev.reg.pmtx);
+
 			n = poll(xtn->ev.buf, nfds, 10000);
+
+			/* poll() worked on the copy taken above, so unregistering a
+			 * descriptor while it was blocked could not withdraw it from the
+			 * call. If the registry changed meanwhile, a returned descriptor
+			 * may no longer be the one that was registered - the number can
+			 * have been closed and handed to a different pipe already - and
+			 * dispatching it would signal a semaphore for something that was
+			 * never ready. Drop the whole batch instead: poll() is level
+			 * triggered, so whatever is genuinely ready is reported again by
+			 * the next call and nothing is lost. */
+			MUTEX_LOCK(&xtn->ev.reg.pmtx);
+			if (epoch != xtn->ev.reg.epoch) n = 0; /* to report nothing */
+			MUTEX_UNLOCK(&xtn->ev.reg.pmtx);
 			if (n > 0)
 			{
 				/* compact the return buffer as poll() doesn't */
@@ -2177,8 +2311,17 @@ static void* iothr_main (void* arg)
 			maxfd = xtn->ev.reg.maxfd;
 			HAK_MEMCPY(&rfds, &xtn->ev.reg.rfds, HAK_SIZEOF(rfds));
 			HAK_MEMCPY(&wfds, &xtn->ev.reg.wfds, HAK_SIZEOF(wfds));
+			epoch = xtn->ev.reg.epoch;
 			MUTEX_UNLOCK(&xtn->ev.reg.smtx);
 			n = select(maxfd + 1, &rfds, &wfds, HAK_NULL, &tv);
+
+			/* the registry changed while select() held a copy of it - the
+			 * result may name a descriptor that is no longer the one that was
+			 * registered. drop the batch; select() is level triggered, so
+			 * anything genuinely ready comes back on the next call. */
+			MUTEX_LOCK(&xtn->ev.reg.smtx);
+			if (epoch != xtn->ev.reg.epoch) n = 0; /* to report nothing */
+			MUTEX_UNLOCK(&xtn->ev.reg.smtx);
 			if (n > 0)
 			{
 				int fd, count = 0;
@@ -2312,20 +2455,7 @@ static void vm_muxwait (hak_t* hak, const hak_ntime_t* dur, hak_vmprim_muxwait_c
 		{
 			--n;
 
-		#if defined(USE_DEVPOLL)
+			if (MUXEVT_FD(xtn->ev.buf[n]) == xtn->iothr.p[0])
-			if (xtn->ev.buf[n].fd == xtn->iothr.p[0])
-		#elif defined(USE_KQUEUE)
-			if (xtn->ev.buf[n].ident == xtn->iothr.p[0])
-		#elif defined(USE_EPOLL)
-			/*if (xtn->ev.buf[n].data.ptr == (void*)HAK_TYPE_MAX(hak_oow_t))*/
-			if (xtn->ev.buf[n].data.fd == xtn->iothr.p[0])
-		#elif defined(USE_POLL)
-			if (xtn->ev.buf[n].fd == xtn->iothr.p[0])
-		#elif defined(USE_SELECT)
-			if (xtn->ev.buf[n].fd == xtn->iothr.p[0])
-		#else
-		#	error UNSUPPORTED
-		#endif
 			{
 				hak_uint8_t u8;
 				while (read(xtn->iothr.p[0], &u8, HAK_SIZEOF(u8)) > 0)
@@ -2339,20 +2469,15 @@ static void vm_muxwait (hak_t* hak, const hak_ntime_t* dur, hak_vmprim_muxwait_c
 				int revents;
 				hak_ooi_t mask;
 
-			#if defined(USE_DEVPOLL)
+			#if defined(USE_KQUEUE)
-				revents = xtn->ev.buf[n].revents;
-			#elif defined(USE_KQUEUE)
 				revents = 0;
+				/* it's "if .. else if" because kqueue filter is either READ or WRITE. */
 				if (xtn->ev.buf[n].filter == EVFILT_READ) revents |= XPOLLIN;
 				else if (xtn->ev.buf[n].filter == EVFILT_WRITE) revents |= XPOLLOUT;
 				if (xtn->ev.buf[n].flags & EV_EOF) revents |= XPOLLHUP;
 				if (xtn->ev.buf[n].flags & EV_ERROR) revents |= XPOLLERR;
-			#elif defined(USE_EPOLL)
+			#else
-				revents = xtn->ev.buf[n].events;
+				revents = MUXEVT_MASK(xtn->ev.buf[n]);
-			#elif defined(USE_POLL)
-				revents = xtn->ev.buf[n].revents;
-			#elif defined(USE_SELECT)
-				revents = xtn->ev.buf[n].events;
 			#endif
 
 				mask = 0;
@@ -2361,19 +2486,7 @@ static void vm_muxwait (hak_t* hak, const hak_ntime_t* dur, hak_vmprim_muxwait_c
 				if (revents & XPOLLERR) mask |= HAK_SEMAPHORE_IO_MASK_ERROR;
 				if (revents & XPOLLHUP) mask |= HAK_SEMAPHORE_IO_MASK_HANGUP;
 
-			#if defined(USE_DEVPOLL)
+				muxwcb(hak, MUXEVT_FD(xtn->ev.buf[n]), mask);
-				muxwcb(hak, xtn->ev.buf[n].fd, mask);
-			#elif defined(USE_KQUEUE)
-				muxwcb(hak, xtn->ev.buf[n].ident, mask);
-			#elif defined(USE_EPOLL)
-				muxwcb(hak, xtn->ev.buf[n].data.fd, mask);
-			#elif defined(USE_POLL)
-				muxwcb(hak, xtn->ev.buf[n].fd, mask);
-			#elif defined(USE_SELECT)
-				muxwcb(hak, xtn->ev.buf[n].fd, mask);
-			#else
-			#	error UNSUPPORTED
-			#endif
 			}
 		}
 		while (n > 0);
@@ -2515,6 +2628,7 @@ static void vm_muxwait (hak_t* hak, const hak_ntime_t* dur, hak_vmprim_muxwait_c
 		revents = xtn->ev.buf[n].revents;
 	#elif defined(USE_KQUEUE)
 		revents = 0;
+		/* it's "if .. else if" because kqueue filter is either READ or WRITE. */
 		if (xtn->ev.buf[n].filter == EVFILT_READ) revents |= XPOLLIN;
 		else if (xtn->ev.buf[n].filter == EVFILT_WRITE) revents |= XPOLLOUT;
 		if (xtn->ev.buf[n].flags & EV_EOF) revents |= XPOLLHUP;
@@ -2721,6 +2835,7 @@ static void dispatch_siginfo (int sig, siginfo_t* si, void* ctx)
 	if (g_sig_state[sig].handler != (hak_uintptr_t)SIG_IGN &&
 	    g_sig_state[sig].handler != (hak_uintptr_t)SIG_DFL)
 	{
+		/* execute the current handler */
 		((sig_handler_t)g_sig_state[sig].handler)(sig);
 	}
 
@@ -2728,6 +2843,9 @@ static void dispatch_siginfo (int sig, siginfo_t* si, void* ctx)
 	    g_sig_state[sig].old_handler != (hak_uintptr_t)SIG_IGN &&
 	    g_sig_state[sig].old_handler != (hak_uintptr_t)SIG_DFL)
 	{
+		/* execute the original remembered handler */
+/* TODO: if the runtime has installed its own signal handler, proably this one must not be called.
+ *       when the runtime registers a single handler, it may optionally request that the previous one should also be invoked? */
 		((void(*)(int, siginfo_t*, void*))g_sig_state[sig].old_handler)(sig, si, ctx);
 	}
 }
@@ -2994,8 +3112,10 @@ static HAK_INLINE void post_sig_to_all_haks (int signo)
 		{
 			xtn_t* xtn = GET_XTN(hak);
 			hak_uint8_t u8;
-			/*hak_abortstd(hak);*/
+
 			u8 = signo & 0xFF;
+			/* write a byte of signal number. vm_getsig() reads this when
+			 * it's invoked by the vm */
 			write(xtn->sigfd.p[1], &u8, HAK_SIZEOF(u8));
 			hak = xtn->next;
 		}
@@ -3137,7 +3257,7 @@ static DWORD WINAPI msw_wait_for_timer_event (LPVOID ctx)
 	return 0;
 }
 
-static HAK_INLINE void start_ticker (void)
+static HAK_INLINE int start_ticker (void)
 {
 	HANDLE thr;
 
@@ -3152,7 +3272,10 @@ static HAK_INLINE void start_ticker (void)
 		 *        and all handles to it have been closed through a call to CloseHandle.
 		 * it is safe to close the handle here */
 		CloseHandle(thr);
+		return 0;
 	}
+
+	return -1;
 }
 
 static HAK_INLINE void stop_ticker (void)
@@ -3207,12 +3330,13 @@ done:
 	DosExit(EXIT_THREAD, 0);
 }
 
-static HAK_INLINE void start_ticker (void)
+static HAK_INLINE int start_ticker (void)
 {
 	static TID tid;
 	os2_tick_done = 0;
 	DosCreateThread(&tid, os2_wait_for_timer_event, 0, 0, 4096);
 	/* TODO: Error check */
+	return 0;
 }
 
 static HAK_INLINE void stop_ticker (void)
@@ -3245,10 +3369,11 @@ static void interrupt dos_timer_intr_handler (void)
 	_chain_intr(dos_prev_timer_intr_handler);
 }
 
-static HAK_INLINE void start_ticker (void)
+static HAK_INLINE int start_ticker (void)
 {
 	dos_prev_timer_intr_handler = _dos_getvect(0x1C);
 	_dos_setvect(0x1C, dos_timer_intr_handler);
+	return 0;
 }
 
 static HAK_INLINE void stop_ticker (void)
@@ -3271,13 +3396,14 @@ static pascal void timer_intr_handler (TMTask* task)
 	PrimeTime((QElem*)&mac_tmtask, TMTASK_DELAY);
 }
 
-static HAK_INLINE void start_ticker (void)
+static HAK_INLINE int start_ticker (void)
 {
 	GetCurrentProcess(&mac_psn);
 	HAK_MEMSET(&mac_tmtask, 0, HAK_SIZEOF(mac_tmtask));
 	mac_tmtask.tmAddr = NewTimerProc (timer_intr_handler);
 	InsXTime((QElem*)&mac_tmtask);
 	PrimeTime((QElem*)&mac_tmtask, TMTASK_DELAY);
+	return 0;
 }
 
 static HAK_INLINE void stop_ticker (void)
@@ -3288,24 +3414,33 @@ static HAK_INLINE void stop_ticker (void)
 
 #elif defined(HAVE_SETITIMER) && defined(SIGVTALRM) && defined(ITIMER_VIRTUAL)
 
-static HAK_INLINE void start_ticker (void)
+static HAK_INLINE int start_ticker (void)
 {
+#if !defined(ITIMER_VIRTUAL_NOT_WORKING)
+	/* a cpu-time timer only fires while the vm is actually computing, which is
+	 * exactly when a process needs preempting, so prefer it where it works. */
 	if (set_signal_handler(SIGVTALRM, SH_HOW_UPSERT, hak_raise_gtick, SA_RESTART) >= 0)
 	{
 		struct itimerval itv;
+
 		itv.it_interval.tv_sec = 0;
 		itv.it_interval.tv_usec = HAK_TICKER_INTERVAL_USECS;
 		itv.it_value.tv_sec = 0;
 		itv.it_value.tv_usec = HAK_TICKER_INTERVAL_USECS;
-		if (setitimer(ITIMER_VIRTUAL, &itv, HAK_NULL) == -1)
+		if (setitimer(ITIMER_VIRTUAL, &itv, HAK_NULL) == 0) return 0;
-		{
+
-			/* WSL supports ITIMER_VIRTUAL only as of windows 10.0.18362.413.
+		/* WSL before windows 10.0.18362.413 rejects ITIMER_VIRTUAL outright. */
-			   the following is a fallback which will get */
 		unset_signal_handler(SIGVTALRM);
+	}
+#endif
 
 #if defined(SIGALRM) && defined(ITIMER_REAL)
+	/* The wall-clock timer. Reached when ITIMER_VIRTUAL is absent, refused at
+	 * runtime, or known not to deliver on this platform. */
 	if (set_signal_handler(SIGALRM, SH_HOW_UPSERT, hak_raise_gtick, SA_RESTART) >= 0)
 	{
+		struct itimerval itv;
+
 		/* i double the interval as ITIMER_REAL is against the wall clock.
 		 * if the underlying system is under heavy load, some signals
 		 * will get lost */
@@ -3313,11 +3448,14 @@ static HAK_INLINE void start_ticker (void)
 		itv.it_interval.tv_usec = HAK_TICKER_INTERVAL_USECS * 2;
 		itv.it_value.tv_sec = 0;
 		itv.it_value.tv_usec = HAK_TICKER_INTERVAL_USECS * 2;
-				setitimer(ITIMER_REAL, &itv, HAK_NULL);
+
+		if (setitimer(ITIMER_REAL, &itv, HAK_NULL) == 0) return 0;
+		unset_signal_handler(SIGALRM);
 	}
 #endif
-		}
+
-	}
+	/* [NOTE] there is no ticker installed if the code reach here */
+	return -1;
 }
 
 static HAK_INLINE void stop_ticker (void)
@@ -3351,7 +3489,7 @@ static HAK_INLINE void stop_ticker (void)
 
 static pid_t ticker_pid = -1;
 
-static HAK_INLINE void start_ticker (void)
+static HAK_INLINE int start_ticker (void)
 {
 #if defined(SIGALRM)
 	if (set_signal_handler(SIGALRM, SH_HOW_UPSERT, hak_raise_gtick, SA_RESTART) >= 0)
@@ -3374,7 +3512,6 @@ static HAK_INLINE void start_ticker (void)
 				nanosleep(&ts, HAK_NULL);
 			#elif defined(HAVE_USLEEP)
 				usleep(HAK_TICKER_INTERVAL_USECS * 2);
-
 			#else
 			#	error UNDEFINED SLEEP
 			#endif
@@ -3386,8 +3523,11 @@ static HAK_INLINE void start_ticker (void)
 		}
 
 		/* parent just carries on. */
+		return 0; /* success */
 	}
 #endif
+
+	return -1;
 }
 
 static HAK_INLINE void stop_ticker (void)
@@ -3548,11 +3688,17 @@ static void dl_cleanup (hak_t* hak)
 #endif
 }
 
-static void* dlopen_pfmod (hak_t* hak, const hak_ooch_t* name, const hak_ooch_t* dirptr, const hak_oow_t dirlen, hak_bch_t* bufptr, hak_oow_t bufcapa)
+/* [NOTE] dirptr/dirlen is a byte string - it is a segment of the modlibdirs
+ *        option, which is stored in the byte form precisely because it ends up
+ *        here and in dlopen(). only 'name' still needs converting. */
+static void* dlopen_pfmod (hak_t* hak, const hak_ooch_t* name, const hak_bch_t* dirptr, const hak_oow_t dirlen, hak_bch_t* bufptr, hak_oow_t bufcapa)
 {
 	void* handle;
 	hak_oow_t len, i, xlen, dlen;
-	hak_oow_t ucslen, bcslen;
+	hak_oow_t bcslen;
+#if defined(HAK_OOCH_IS_UCH)
+	hak_oow_t ucslen;
+#endif
 
 	/* opening a primitive function module - mostly libhak-xxxx.
 	 * if PFMODPREFIX is absolute, never use PFMODDIR */
@@ -3563,13 +3709,7 @@ static void* dlopen_pfmod (hak_t* hak, const hak_ooch_t* name, const hak_ooch_t*
 	}
 	else if (dirptr)
 	{
-		xlen = dirlen;
-		dlen = bufcapa;
-	#if defined(HAK_OOCH_IS_UCH)
-		if (hak_convootobchars(hak, dirptr, &xlen, bufptr, &dlen) <= -1) return HAK_NULL;
-	#else
 		dlen = hak_copy_bchars_to_bcstr(bufptr, bufcapa, dirptr, dirlen);
-	#endif
 
 		if (dlen > 0 && bufptr[dlen - 1] != HAK_DFL_PATH_SEP)
 		{
@@ -3705,25 +3845,28 @@ static void* dl_open (hak_t* hak, const hak_ooch_t* name, int flags)
 {
 #if defined(USE_LTDL) || defined(USE_DLFCN) || defined(USE_MACH_O_DYLD)
 	hak_bch_t stabuf[128], * bufptr;
-	hak_oow_t ucslen, bcslen, bufcapa;
 	void* handle = HAK_NULL;
+	hak_oow_t bufcapa;
+	const hak_bch_t* modlibdirs;
+	#if defined(HAK_OOCH_IS_UCH)
+	hak_oow_t ucslen;
+	#endif
+
+	modlibdirs = hak->option.modlibdirs_b;
 
 	#if defined(HAK_OOCH_IS_UCH)
 	if (hak_convootobcstr(hak, name, &ucslen, HAK_NULL, &bufcapa) <= -1) return HAK_NULL;
-
-	if (hak->option.mod[0].len > 0)
-	{
-		/* multiple directories separated by a colon can be specified for HAK_MOD_LIBDIRS
-		 * however, use the total length to secure space just for simplicity */
-		ucslen = hak->option.mod[0].len;
-		if (hak_convootobchars(hak, hak->option.mod[0].ptr, &ucslen, HAK_NULL, &bcslen) <= -1) return HAK_NULL;
-		bufcapa += bcslen;
-	}
 	#else
 	bufcapa = hak_count_bcstr(name);
-	bufcapa += (hak->option.mod[0].len > 0)? hak->option.mod[0].len: HAK_COUNTOF(HAK_DEFAULT_PFMODDIR);
 	#endif
 
+	/* modlibdirs is stored in the byte form too, so no conversion is needed
+	 * here. multiple directories separated by a colon can be specified for
+	 * HAK_OPT_MODLIBDIRS - use the total length to secure space, for
+	 * simplicity. */
+	bufcapa += (modlibdirs && modlibdirs[0] != '\0')?
+		hak_count_bcstr(modlibdirs): HAK_COUNTOF(HAK_DEFAULT_PFMODDIR);
+
 	/* HAK_COUNTOF(HAK_DEFAULT_PFMODPREFIX) and HAK_COUNTOF(HAK_DEFAULT_PFMODPOSTIFX)
 	 * include the terminating nulls. Never mind about the extra 2 characters. */
 	bufcapa += HAK_COUNTOF(HAK_DEFAULT_PFMODPREFIX) + HAK_COUNTOF(HAK_DEFAULT_PFMODPOSTFIX) + 1;
@@ -3737,12 +3880,12 @@ static void* dl_open (hak_t* hak, const hak_ooch_t* name, int flags)
 
 	if (flags & HAK_VMPRIM_DLOPEN_PFMOD)
 	{
-		if (hak->option.mod[0].len > 0)
+		if (modlibdirs && modlibdirs[0] != '\0')
 		{
-			const hak_ooch_t* ptr, * end, * seg;
+			const hak_bch_t* ptr, * end, * seg;
 
-			ptr = hak->option.mod[0].ptr;
+			ptr = modlibdirs;
-			end = hak->option.mod[0].ptr + hak->option.mod[0].len;
+			end = modlibdirs + hak_count_bcstr(modlibdirs);
 			seg = ptr;
 
 			while (ptr <= end)
@@ -3945,8 +4088,8 @@ static void cb_on_option (hak_t* hak, hak_option_t id, const void* value)
 	xtn_t* xtn = GET_XTN(hak);
 	int fd;
 
-	if (id != HAK_LOG_TARGET_BCSTR && id != HAK_LOG_TARGET_UCSTR &&
+	if (id != HAK_OPT_LOG_TARGET_BCSTR && id != HAK_OPT_LOG_TARGET_UCSTR &&
-	    id != HAK_LOG_TARGET_BCS && id != HAK_LOG_TARGET_UCS) return; /* return success. not interested */
+	    id != HAK_OPT_LOG_TARGET_BCS && id != HAK_OPT_LOG_TARGET_UCS) return; /* return success. not interested */
 
 #if defined(_WIN32)
 	#if defined(HAK_OOCH_IS_UCH) && (HAK_SIZEOF_UCH_T == HAK_SIZEOF_WCHAR_T)
@@ -4193,6 +4336,7 @@ static int cb_vm_startup (hak_t* hak)
 	FD_ZERO(&xtn->ev.reg.rfds);
 	FD_ZERO(&xtn->ev.reg.wfds);
 	xtn->ev.reg.maxfd = -1;
+	xtn->ev.reg.epoch = 0;
 	MUTEX_INIT(&xtn->ev.reg.smtx);
 #endif /* USE_DEVPOLL */
 
@@ -4498,12 +4642,13 @@ static HAK_INLINE int open_cci_stream (hak_t* hak, hak_io_cciarg_t* arg)
 	xtn_t* xtn = GET_XTN(hak);
 	bb_t* bb = HAK_NULL;
 
-/* TOOD: support predefined include directory as well */
 	if (arg->includer)
 	{
 		/* includee */
 		hak_oow_t ucslen, bcslen, parlen;
 		const hak_bch_t* fn, * fb;
+		int attempt_incdirs;
+		const hak_bch_t* incdirs_ptr;
 
 	#if defined(HAK_OOCH_IS_UCH)
 		if (hak_convootobcstr(hak, arg->name, &ucslen, HAK_NULL, &bcslen) <= -1) goto oops;
@@ -4517,15 +4662,17 @@ static HAK_INLINE int open_cci_stream (hak_t* hak, hak_io_cciarg_t* arg)
 		{
 			fb = "";
 			parlen = 0;
+			attempt_incdirs = 0;
 		}
 		else
 		{
 			fb = hak_get_base_name_from_bcstr_path(fn);
 			parlen = fb - fn;
+			attempt_incdirs = !((arg->name[0] == '.' && arg->name[1] == '/') || (arg->name[0] == '.' && arg->name[1] == '.' && arg->name[2] == '/'));
 		}
 
 		bb = (bb_t*)hak_callocmem(hak, HAK_SIZEOF(*bb) + (HAK_SIZEOF(hak_bch_t) * (parlen + bcslen + 1)));
-		if (!bb) goto oops;
+		if (HAK_UNLIKELY(!bb)) goto oops;
 
 		bb->fn = (hak_bch_t*)(bb + 1);
 		hak_copy_bchars(bb->fn, fn, parlen);
@@ -4535,9 +4682,43 @@ static HAK_INLINE int open_cci_stream (hak_t* hak, hak_io_cciarg_t* arg)
 		hak_copy_bcstr(&bb->fn[parlen], bcslen + 1, arg->name);
 	#endif
 
+		incdirs_ptr = hak->option.incdirs_b;
+retry:
 		bb->fp = fopen(bb->fn, FOPEN_R_FLAGS);
 		if (!bb->fp)
 		{
+			if ((errno == ENOENT || errno == ENOTDIR) && attempt_incdirs && incdirs_ptr && incdirs_ptr[0] != '\0')
+			{
+				hak_oow_t incdir_bcslen;
+				const hak_bch_t* colon;
+
+				hak_freemem(hak, bb); bb = HAK_NULL;
+
+				/* incdirs is kept in the byte form as well, so the directory part
+				 * needs no conversion here - only the include name does. */
+				colon = hak_find_bchar_in_bcstr(incdirs_ptr, ':');
+				incdir_bcslen = colon? (hak_oow_t)(colon - incdirs_ptr): hak_count_bcstr(incdirs_ptr);
+
+				bb = (bb_t*)hak_callocmem(hak, HAK_SIZEOF(*bb) + (HAK_SIZEOF(hak_bch_t) * (incdir_bcslen + bcslen + 2)));
+				if (HAK_UNLIKELY(!bb)) goto oops;
+
+				bb->fn = (hak_bch_t*)(bb + 1);
+
+/* TODO: i need to support different directory separator */
+				hak_copy_bchars(bb->fn, incdirs_ptr, incdir_bcslen);
+				if (incdir_bcslen > 0 && bb->fn[incdir_bcslen - 1] != '/') bb->fn[incdir_bcslen++] = '/';
+			#if defined(HAK_OOCH_IS_UCH)
+				hak_convootobcstr(hak, arg->name, &ucslen, &bb->fn[incdir_bcslen], &bcslen);
+			#else
+				hak_copy_bcstr(&bb->fn[incdir_bcslen], bcslen + 1, arg->name);
+			#endif
+
+				incdirs_ptr = colon? colon + 1: HAK_NULL;
+
+/*printf("RETRYING bb->fn [%s]\n", bb->fn);*/
+				goto retry;
+			}
+
 			hak_seterrbfmt(hak, HAK_EIOERR, "unable to open %hs", bb->fn);
 			goto oops;
 		}
@@ -4545,6 +4726,15 @@ static HAK_INLINE int open_cci_stream (hak_t* hak, hak_io_cciarg_t* arg)
 	else
 	{
 		/* main stream  */
+
+		/* [NOTE]
+		 *   in the current implementation, the main stream is rarely used read
+		 *   because the input the the reader/compiler is fed via hak_feed() and its relatives.
+		 *   this part doesn't really open the specified file.
+		 */
+
+		/* TODO: make if hak_feed() is going to be used or not.
+		 *       if it's not used, it can open it as usual as xtn->cci_path point to the file name anyways */
 		hak_oow_t pathlen;
 
 		pathlen = xtn->cci_path? hak_count_bcstr(xtn->cci_path): 0;
@@ -5114,24 +5304,74 @@ int hak_attachudiostdwithucstr (hak_t* hak, const hak_uch_t* udi_file, const hak
 
 /* ========================================================================= */
 
+#if defined(HAK_ATOMIC_LOAD) && defined(HAK_ATOMIC_ADD_FETCH) && \
+    defined(HAK_ATOMIC_SUB_FETCH) && defined(HAK_ATOMIC_CAS_BOOL)
+#	define USE_TICKER_ATOMICS
+#endif
+
 static hak_uint32_t ticker_started = 0;
 
-void hak_start_ticker (void)
+int hak_start_ticker (void)
 {
-/* TODO: use atomic op */
+#if defined(USE_TICKER_ATOMICS)
+	hak_uint32_t x;
+	/* ACQ_REL rather than RELAXED - this counter gates the one-time
+	 * start_ticker() call, so it must carry ordering and not merely be
+	 * indivisible. The __sync_* fallbacks ignore the memory order argument
+	 * and are already sequentially consistent. */
+	x = HAK_ATOMIC_ADD_FETCH(&ticker_started, 1, HAK_ATOMIC_ACQ_REL);
+	if (x == 1)
+#else
 	if (++ticker_started == 1)
+#endif
 	{
-		start_ticker();
+		int n;
+		n = start_ticker();
+		if (n <= -1)
+		{
+			/* roll the claim back, so a retry can take it again and an
+			 * unbalanced hak_stop_ticker() cannot tear down a ticker that was
+			 * never installed. */
+		#if defined(USE_TICKER_ATOMICS)
+			HAK_ATOMIC_SUB_FETCH(&ticker_started, 1, HAK_ATOMIC_ACQ_REL);
+		#else
+			ticker_started--;
+		#endif
+
+			return -1;
 		}
+
+		return 1;
+	}
+
+	/* [NOTE] potentially this answer of 0 could be misleading if hak_start_ticker()
+	 *        is called in parallel without a guard/mutex and start_ticker() fails mid-loop. */
+	return 0; /* ok. already started */
 }
 
 void hak_stop_ticker (void)
 {
-/* TODO: use atomic op */
+#if defined(USE_TICKER_ATOMICS)
-	if (ticker_started > 0 && --ticker_started == 0)
+	hak_uint32_t old;
+
+	/* decrement only if non-zero - ticker_started is unsigned, so an
+	 * unbalanced stop would otherwise wrap it round to its maximum. no single
+	 * atomic operation expresses "decrement if greater than zero". */
+	old = HAK_ATOMIC_LOAD(&ticker_started, HAK_ATOMIC_ACQUIRE);
+	while (old > 0)
 	{
-		stop_ticker();
+		if (HAK_ATOMIC_CAS_BOOL(&ticker_started, &old, old - 1, HAK_ATOMIC_ACQ_REL, HAK_ATOMIC_ACQUIRE)) break;
+	#if !defined(HAK_ATOMIC_CAS_BOOL_YIELD_OLDVAL)
+		/* __sync_bool_compare_and_swap() does not write the observed value
+		 * back into old on failure, so reload it before retrying. */
+		old = HAK_ATOMIC_LOAD(&ticker_started, HAK_ATOMIC_ACQUIRE);
+	#endif
 	}
+
+	if (old == 1) stop_ticker();
+#else
+	if (ticker_started > 0 && --ticker_started == 0) stop_ticker();
+#endif
 }
 
 /* ========================================================================== */

lib/x-client.c

@@ -212,7 +212,7 @@ hak_client_t* hak_client_open (hak_mmgr_t* mmgr, hak_oow_t xtnsize, hak_client_p
 	/* the dummy hak is used for this client to perform primitive operations
 	 * such as getting system time or logging. so the heap size doesn't
 	 * need to be changed from the tiny value set above. */
-	hak_setoption (client->dummy_hak, HAK_LOG_MASK, &client->cfg.logmask);
+	hak_setoption (client->dummy_hak, HAK_OPT_LOG_MASK, &client->cfg.logmask);
 	hak_setcmgr (client->dummy_hak, client->_cmgr);
 
 	return client;
@@ -258,7 +258,7 @@ int hak_client_setoption (hak_client_t* client, hak_client_option_t id, const vo
 				 * existing hak instances inside worker threads won't get
 				 * affected. new hak instances to be created later
 				 * is supposed to use the new value */
-				hak_setoption (client->dummy_hak, HAK_LOG_MASK, value);
+				hak_setoption (client->dummy_hak, HAK_OPT_LOG_MASK, value);
 			}
 			return 0;
 	}

lib/x-server.c

@@ -1177,14 +1177,14 @@ hak_server_t* hak_server_open (hak_mmgr_t* mmgr, hak_oow_t xtnsize, hak_server_p
 	/* the dummy hak is used for this server to perform primitive operations
 	 * such as getting system time or logging. so the heap size doesn't
 	 * need to be changed from the tiny value set above. */
-	hak_setoption (server->dummy_hak, HAK_LOG_MASK, &server->cfg.logmask);
+	hak_setoption (server->dummy_hak, HAK_OPT_LOG_MASK, &server->cfg.logmask);
 	hak_setcmgr (server->dummy_hak, hak_server_getcmgr(server));
-	hak_getoption (server->dummy_hak, HAK_TRAIT, &trait);
+	hak_getoption (server->dummy_hak, HAK_OPT_TRAIT, &trait);
 #if defined(HAK_BUILD_DEBUG)
 	if (server->cfg.trait & HAK_SERVER_TRAIT_DEBUG_GC) trait |= HAK_TRAIT_DEBUG_GC;
 	if (server->cfg.trait & HAK_SERVER_TRAIT_DEBUG_BIGINT) trait |= HAK_TRAIT_DEBUG_BIGINT;
 #endif
-	hak_setoption (server->dummy_hak, HAK_TRAIT, &trait);
+	hak_setoption (server->dummy_hak, HAK_OPT_TRAIT, &trait);
 
 	return server;
 
@@ -1517,17 +1517,17 @@ static int init_worker_hak (hak_server_worker_t* worker)
 	xtn = (worker_hak_xtn_t*)hak_getxtn(hak);
 	xtn->worker = worker;
 
-	hak_setoption(hak, HAK_MOD_INCTX, &server->cfg.module_inctx);
+	hak_setoption(hak, HAK_OPT_MODINCTX, &server->cfg.module_inctx);
-	hak_setoption(hak, HAK_LOG_MASK, &server->cfg.logmask);
+	hak_setoption(hak, HAK_OPT_LOG_MASK, &server->cfg.logmask);
 	hak_setcmgr(hak, hak_server_getcmgr(server));
 
-	hak_getoption(hak, HAK_TRAIT, &trait);
+	hak_getoption(hak, HAK_OPT_TRAIT, &trait);
 #if defined(HAK_BUILD_DEBUG)
 	if (server->cfg.trait & HAK_SERVER_TRAIT_DEBUG_GC) trait |= HAK_TRAIT_DEBUG_GC;
 	if (server->cfg.trait & HAK_SERVER_TRAIT_DEBUG_BIGINT) trait |= HAK_TRAIT_DEBUG_BIGINT;
 #endif
 	trait |= HAK_TRAIT_LANG_ENABLE_EOL;
-	hak_setoption(hak, HAK_TRAIT, &trait);
+	hak_setoption(hak, HAK_OPT_TRAIT, &trait);
 
 	HAK_MEMSET(&hakcb, 0, HAK_SIZEOF(hakcb));
 	/*hakcb.fini = fini_hak;
@@ -2050,12 +2050,12 @@ int hak_server_setoption (hak_server_t* server, hak_server_option_t id, const vo
 				 * is supposed to use the new value */
 				hak_bitmask_t trait;
 
-				hak_getoption (server->dummy_hak, HAK_TRAIT, &trait);
+				hak_getoption (server->dummy_hak, HAK_OPT_TRAIT, &trait);
 			#if defined(HAK_BUILD_DEBUG)
 				if (server->cfg.trait & HAK_SERVER_TRAIT_DEBUG_GC) trait |= HAK_TRAIT_DEBUG_GC;
 				if (server->cfg.trait & HAK_SERVER_TRAIT_DEBUG_BIGINT) trait |= HAK_TRAIT_DEBUG_BIGINT;
 			#endif
-				hak_setoption (server->dummy_hak, HAK_TRAIT, &trait);
+				hak_setoption (server->dummy_hak, HAK_OPT_TRAIT, &trait);
 			}
 			return 0;
 
@@ -2067,7 +2067,7 @@ int hak_server_setoption (hak_server_t* server, hak_server_option_t id, const vo
 				 * existing hak instances inside worker threads won't get
 				 * affected. new hak instances to be created later
 				 * is supposed to use the new value */
-				hak_setoption (server->dummy_hak, HAK_LOG_MASK, value);
+				hak_setoption (server->dummy_hak, HAK_OPT_LOG_MASK, value);
 			}
 			return 0;
 

mod/core.c

@@ -584,6 +584,9 @@ static hak_pfinfo_t pfinfos[] =
 
 /* TODO: add more builtin primitives here... */
 	{ "abs",                { HAK_PFBASE_FUNC, hak_pf_number_abs,             1,  1 } },
+
+	{ "active-process",     { HAK_PFBASE_FUNC, hak_pf_process_current,        0,  0 } },
+
 	{ "basicAt",            { HAK_PFBASE_FUNC, pf_core_basic_at,              2,  2 } },
 	{ "basicAtPut",         { HAK_PFBASE_FUNC, pf_core_basic_at_put,          3,  3 } },
 	{ "basicNew",           { HAK_PFBASE_FUNC, pf_core_basic_new,             1,  2 } },
@@ -609,17 +612,40 @@ static hak_pfinfo_t pfinfos[] =
 	{ "eql?",               { HAK_PFBASE_FUNC, hak_pf_eql,                    2,  2 } },
 	{ "eqv?",               { HAK_PFBASE_FUNC, hak_pf_eqv,                    2,  2 } },
 
+	{ "fork",               { HAK_PFBASE_FUNC, hak_pf_process_fork,           1,  HAK_TYPE_MAX(hak_oow_t) } },
 	{ "instRespondsTo",     { HAK_PFBASE_FUNC, pf_core_inst_responds_to,      2,  2 } },
 
 	{ "nqk?",               { HAK_PFBASE_FUNC, hak_pf_nqk,                    2,  2 } },
 	{ "nql?",               { HAK_PFBASE_FUNC, hak_pf_nql,                    2,  2 } },
 	{ "nqv?",               { HAK_PFBASE_FUNC, hak_pf_nqv,                    2,  2 } },
 
+     { "object-new",         { HAK_PFBASE_FUNC, hak_pf_object_new,             1,  2 } },
+
 	{ "primAt",             { HAK_PFBASE_FUNC, pf_core_prim_at,               2,  2 } },
 	{ "primAtPut",          { HAK_PFBASE_FUNC, pf_core_prim_at_put,           3,  3 } },
+
+	{ "resume",             { HAK_PFBASE_FUNC, hak_pf_process_resume,         1,  1 } },
+
+	{ "sem-new",            { HAK_PFBASE_FUNC, hak_pf_semaphore_new,          0,  1 } },
+	{ "sem-signal",         { HAK_PFBASE_FUNC, hak_pf_semaphore_signal,       1,  3 } },
+	{ "sem-signal-on-input",  { HAK_PFBASE_FUNC, hak_pf_semaphore_signal_on_input,  2,  2 } },
+	{ "sem-signal-on-output", { HAK_PFBASE_FUNC, hak_pf_semaphore_signal_on_output, 2,  2 } },
+	{ "sem-unsignal",       { HAK_PFBASE_FUNC, hak_pf_semaphore_unsignal,     1,  1 } },
+	{ "sem-wait",           { HAK_PFBASE_FUNC, hak_pf_semaphore_wait,         1,  1 } },
+	{ "semgr-add",          { HAK_PFBASE_FUNC, hak_pf_semaphore_group_add_semaphore,    1,  2 } },
+	{ "semgr-new",          { HAK_PFBASE_FUNC, hak_pf_semaphore_group_new,              0,  0 } },
+	{ "semgr-remove",       { HAK_PFBASE_FUNC, hak_pf_semaphore_group_remove_semaphore, 1,  2 } },
+	{ "semgr-wait",         { HAK_PFBASE_FUNC, hak_pf_semaphore_group_wait,             1,  1 } },
+
 	{ "slice",              { HAK_PFBASE_FUNC, pf_core_slice,                 3,  3 } },
 	{ "smooiToChar",        { HAK_PFBASE_FUNC, pf_core_smooi_to_char,         1,  1 } },
 	{ "sqrt",               { HAK_PFBASE_FUNC, hak_pf_number_sqrt,            1,  1 } },
+
+	{ "suspend",            { HAK_PFBASE_FUNC, hak_pf_process_suspend,        0,  1 } },
+	{ "terminate",          { HAK_PFBASE_FUNC, hak_pf_process_terminate,      0,  1 } },
+	{ "terminate-all",      { HAK_PFBASE_FUNC, hak_pf_process_terminate_all,  0,  0 } },
+	{ "yield",              { HAK_PFBASE_FUNC, hak_pf_process_yield,          0,  0 } },
+
 	{ "~=",                 { HAK_PFBASE_FUNC, hak_pf_number_ne,              2,  2 } },
 };
 

mod/sys.c

@@ -31,9 +31,8 @@
 #endif
 
 #include "_sys.h"
-#include <hak-hnd.h>
+#include "../lib/hak-prv.h"
 #include <hak-pio.h>
-#include <hak-str.h>
 #include <stdlib.h>
 #include <signal.h>
 
@@ -43,7 +42,6 @@
 #	include <unistd.h>
 #	include <fcntl.h>
 #	include <errno.h>
-#	include <sys/syscall.h>
 #endif
 
 #if defined(HAVE_SYS_TIME_H)
@@ -175,7 +173,7 @@ static hak_pfrc_t pf_sys_random (hak_t* hak, hak_mod_t* mod, hak_ooi_t nargs)
  * sys.read and sys.write follow the non-blocking contract: they return the
  * byte count, 0 at end of file, or -1 when the handle would have blocked.
  * -1 is an ordinary outcome - the caller is expected to wait on a semaphore
- * bound with sem-signal-on-input/-output and try again. Only a genuine
+ * bound with core.sem-signal-on-input/-output and try again. Only a genuine
  * failure raises.
  * ------------------------------------------------------------------------ */
 
@@ -814,6 +812,13 @@ static hak_pfinfo_t pfinfos[] =
 	{ "pwait",         { HAK_PFBASE_FUNC,        pf_sys_pwait,        1,  1 } },
 	{ "random",        { HAK_PFBASE_FUNC,        pf_sys_random,       0,  0 } },
 	{ "read",          { HAK_PFBASE_FUNC,        pf_sys_read,         2,  4 } },
+
+	{ "sig-catch",     { HAK_PFBASE_FUNC,        hak_pf_system_catch_sig,   1,  1 } },
+	{ "sig-get",       { HAK_PFBASE_FUNC,        hak_pf_system_get_sig,     0,  0 } },
+	{ "sig-getfd",     { HAK_PFBASE_FUNC,        hak_pf_system_get_sigfd,   0,  0 } },
+	{ "sig-set",       { HAK_PFBASE_FUNC,        hak_pf_system_set_sig,     1,  1 } },
+	{ "sig-uncatch",   { HAK_PFBASE_FUNC,        hak_pf_system_uncatch_sig, 1,  1 } },
+
 	{ "srandom",       { HAK_PFBASE_FUNC,        pf_sys_srandom,      1,  1 } },
 	{ "stime",         { HAK_PFBASE_FUNC,        pf_sys_stime,        1,  1 } },
 	{ "time",          { HAK_PFBASE_FUNC,        pf_sys_time,         0,  0 } },

src/Collection.hak

@@ -42,6 +42,9 @@ class FixedSizedCollection: IndexedCollection {
 class[#varying] Array: FixedSizedCollection {
 }
 
+class[#byte #varying] ByteArray: FixedSizedCollection {
+}
+
 class[#char #varying] String: FixedSizedCollection {
 	fun[#class] initValue() {
 		##return '\0'

src/Mutex.hak

@@ -0,0 +1,36 @@
+##$include-once "Semaphore.hak"
+
+class[#uncopyable] Mutex: Object(
+	_sem
+	_owner	
+) {
+	fun[#ci] new() {
+		self._sem := (Semaphore:forMutex)
+		self._owner := nil
+		return self
+	}
+
+	## TODO: support relay of variable arguments to (fnc args...)
+	##fun critical(fnc args...) {
+	fun critical(fnc) {
+		| p ex r |
+
+		p := (core.active-process)
+
+		## already the owner: just run the body. the outermost critical
+		## is the one that releases, so nesting needs no bookkeeping.
+		if (eqv? p self._owner) { return (fnc) }
+
+		self._sem:wait
+		self._owner := p
+
+		## TODO: update code to use 'finally' if 'finally' is implemented...
+		try { r := (fnc) } catch (e) { ex := e }
+
+		self._owner := nil
+		self._sem:signal
+
+		if (nqv? ex nil) { throw ex }
+		return r
+	}
+}

src/Object.hak

@@ -0,0 +1,76 @@
+class Apex {
+	fun isNil?() { return false }
+	fun notNil?() { return true }
+
+	fun[#class] basicNew(size) {
+		return (core.basicNew self size)
+	}
+
+	fun[#class] respondsTo(mthname) {
+		return (core.classRespondsTo self mthname)
+	}
+
+	fun respondsTo(mthname) {
+		return (core.instRespondsTo self mthname)
+	}
+
+	fun primAt(pos) {
+		return (core.primAt self pos)
+	}
+
+	fun primtAtPut(pos value) {
+		return (core.primAtPut self pos value)
+	}
+
+	fun basicAt(pos) {
+		return (core.basicAt self pos)
+	}
+
+	fun basicAtPut(pos value) {
+		return (core.basicAtPut self pos value)
+	}
+
+	fun basicSize() {
+		return (core.basicSize self)
+	}
+
+	## TODO: ...
+	fun == (oprnd) { return (== self oprnd) }
+	fun != (oprnd) { return (!= self oprnd) }
+	## TODO: fun perform(name ...) {}
+}
+ 
+class[#uncopyable #varying #limited #final] Class: Apex (
+	_name
+	_mdic
+	_spec
+	_selfspec
+	_superclass
+	_nivars_super
+	_ibrand
+	_ivarnames
+	_cvarnames
+) {
+	fun name() {
+		##return (core.className self)
+		return _class
+	}
+
+	fun instanceVariableNames() {
+		## TODO: this still returns nil as the acutal manipulation of the field has not been implemented
+		return _ivarnames
+	}
+
+	fun classVariableNames() {
+		## TODO: this still returns nil as the acutal manipulation of the field has not been implemented
+		return _cvarnames
+	}
+}
+
+class UndefinedObject: Apex {
+	fun isNil?() { return true }
+	fun notNil?() { return false }
+}
+
+class Object: Apex {
+}

src/Process.hak

@@ -0,0 +1,31 @@
+##$include-once "Object.hak"
+
+class[#uncopyable #final #limited #varying] Process: Object(
+	_initial_context
+     _current_context
+     _id
+     _state
+	_sp
+	_st
+	_exsp
+	_exst
+	_clsp
+	_clst
+	_fsp
+	_fst
+	_sched_prev
+	_sched_next
+	_sem_wawit_prev
+	_sem_wait_next
+	_sem
+) {
+
+	## TODO: add many read-only methods
+	fun id() {
+		return self._id
+	}
+
+	fun state() {
+		return self._state
+	}
+}

src/Semaphore.hak

@@ -0,0 +1,74 @@
+##$include-once "Object.hak"
+
+class[#uncopyable] Semaphore: Object(
+	_waiting_first
+	_wait_last
+	_count
+	_subtype
+	_index		
+	_ftime_sec_or_handle
+	_ftime_nsec_or_type
+	_signal_action
+	_group
+	_grm_prev
+	_grm_next
+) {
+	fun[#class] new() {
+		return (core.sem-new 0)
+	}
+
+	fun[#class] forMutex() {
+		return (core.sem-new 1)
+	}
+
+	fun signal() {
+		return (core.sem-signal self 0 0)
+	}
+
+	fun signalAfter(secs nsecs) {
+		return (core.sem-signal self secs nsecs)
+	}
+
+	fun signalOnInput(handle) {
+		return (core.sem-signal-on-input self handle)
+	}
+
+	fun signalOnOutput(handle) {
+		return (core.sem-signal-on-output self handle)
+	}
+
+	fun unsignal() {
+		return (core.sem-unsignal self)
+	}
+
+	fun wait() {
+		return (core.sem-wait self)
+	}
+}
+
+class[#uncopyable] SemaphoreGroup: Object(
+	_waiting_first
+	_waiting_last
+	_sem_unsig_first
+	_sem_unsig_last
+	_sem_sig_first
+	_sem_sig_last
+	_sem_io_count
+	_sem_count
+) {
+	fun[#class] new() {
+		return (core.semgr-new)
+	}
+
+	fun add(sem) {
+		return (core.semgr-add self sem)
+	}
+
+	fun remove(sem) {
+		return (core.semgr-remove self sem)
+	}
+
+	fun wait() {
+		return (core.semgr-wait self)
+	}
+}

src/kernel.hak

@@ -1,84 +1,11 @@
-class Apex {
+$include "Object.hak"
-	fun isNil?() { return false }
-	fun notNil?() { return true }
-
-	fun[#class] basicNew(size) {
-		return (core.basicNew self size)
-	}
-
-	fun[#class] respondsTo(mthname) {
-		return (core.classRespondsTo self mthname)
-	}
-
-	fun respondsTo(mthname) {
-		return (core.instRespondsTo self mthname)
-	}
-
-	fun primAt(pos) {
-		return (core.primAt self pos)
-	}
-
-	fun primtAtPut(pos value) {
-		return (core.primAtPut self pos value)
-	}
-
-	fun basicAt(pos) {
-		return (core.basicAt self pos)
-	}
-
-	fun basicAtPut(pos value) {
-		return (core.basicAtPut self pos value)
-	}
-
-	fun basicSize() {
-		return (core.basicSize self)
-	}
-
-	## TODO: ...
-	fun == (oprnd) { return (== self oprnd) }
-	fun != (oprnd) { return (!= self oprnd) }
-	## TODO: fun perform(name ...) {}
-}
-
-class[#uncopyable #varying #limited #final] Class: Apex (
-	_name
-	_mdic
-	_spec
-	_selfspec
-	_superclass
-	_nivars_super
-	_ibrand
-	_ivarnames
-	_cvarnames
-) {
-	fun name() {
-		##return (core.className self)
-		return _class
-	}
-
-	fun instanceVariableNames() {
-		## TODO: this still returns nil as the acutal manipulation of the field has not been implemented
-		return _ivarnames
-	}
-
-	fun classVariableNames() {
-		## TODO: this still returns nil as the acutal manipulation of the field has not been implemented
-		return _cvarnames
-	}
-}
-
-class UndefinedObject: Apex {
-	fun isNil?() { return true }
-	fun notNil?() { return false }
-}
-
-class Object: Apex {
-}
-
-## ---------------------------------------------------------------------------------
-
 $include "Magnitude.hak"
 $include "Collection.hak"
+
+$include "Semaphore.hak"
+$include "Mutex.hak"
+
+$include "Process.hak"
 ##$include "System.hak"
 
 ## ---------------------------------------------------------------------------------

src/proc.hak

@@ -37,9 +37,9 @@ class ChildGroup(
 	sigsem  ## the shared semaphore; only in shared mode
 ) {
 	fun[#ci] new() {
-		set sg (semgr-new)
+		set sg (core.semgr-new)
-		set tmo (sem-new)
+		set tmo (core.sem-new)
-		semgr-add sg tmo
+		core.semgr-add sg tmo
 		set capa 8
 		set kids (core.basicNew Array 8)
 		set nkids 0
@@ -107,16 +107,16 @@ class ChildGroup(
 			## semaphore on the signal descriptor for the whole group, once.
 			if (not self.shared) {
 				set shared true
-				system-catch-sig sys.SIGCHLD
+				sys.sig-catch sys.SIGCHLD
-				set sigsem (sem-new)
+				set sigsem (core.sem-new)
-				semgr-add self.sg self.sigsem
+				core.semgr-add self.sg self.sigsem
-				sem-signal-on-input self.sigsem (system-get-sigfd)
+				core.sem-signal-on-input self.sigsem (sys.sig-getfd)
 			}
 		} else {
 			## A handle of its own, so a wakeup identifies this child directly.
-			sem := (sem-new)
+			sem := (core.sem-new)
-			semgr-add self.sg sem
+			core.semgr-add self.sg sem
-			sem-signal-on-input sem xh
+			core.sem-signal-on-input sem xh
 		}
 
 		kid := (core.basicNew Array 6)
@@ -171,16 +171,16 @@ class ChildGroup(
 		if (not (nil? kid)) { return kid }
 
 		while true {
-			sem-signal self.tmo secs 0
+			core.sem-signal self.tmo secs 0
-			w := (semgr-wait self.sg)
+			w := (core.semgr-wait self.sg)
-			sem-unsignal self.tmo
+			core.sem-unsignal self.tmo
 
 			if (eqv? w self.tmo) { return nil }
 
 			if self.shared {
 				## the signal descriptor spoke: take the byte, then look at
 				## everyone, since one SIGCHLD may stand for several exits
-				system-get-sig
+				sys.sig-get
 				kid := (self:finished)
 				if (not (nil? kid)) { return kid }
 				## otherwise it was a SIGCHLD for a child of the host
@@ -188,7 +188,7 @@ class ChildGroup(
 			} else {
 				kid := (self:kid-of-sem w)
 				if (not (nil? kid)) {
-					sem-unsignal w
+					core.sem-unsignal w
 					return kid
 				}
 			}
@@ -210,8 +210,8 @@ class ChildGroup(
 		| sem |
 		sem := (core.basicAt kid 5)
 		if (not (nil? sem)) {
-			sem-unsignal sem
+			core.sem-unsignal sem
-			semgr-remove self.sg sem
+			core.semgr-remove self.sg sem
 		}
 		self:forget kid
 		sys.pclose (core.basicAt kid 0)
@@ -227,8 +227,8 @@ class ChildGroup(
 			i := (+ i 1)
 		}
 		if self.shared {
-			sem-unsignal self.sigsem
+			core.sem-unsignal self.sigsem
-			system-uncatch-sig sys.SIGCHLD
+			sys.sig-uncatch sys.SIGCHLD
 			set shared false
 		}
 	}

t/Makefile.am

@@ -5,7 +5,8 @@ AM_CPPFLAGS = \
 	-I$(abs_builddir)/../lib \
 	-I$(abs_srcdir) \
 	-I$(abs_srcdir)/../lib \
-	-I$(includedir)
+	-I$(includedir) \
+	-DHAK_TEST_MODLIBDIRS='"@abs_top_builddir@/mod:@abs_top_builddir@/mod/.libs"'
 LDADD = ../lib/libhak.la
 
 check_SCRIPTS = \
@@ -13,14 +14,19 @@ check_SCRIPTS = \
 	cons-01.hak \
 	dic-01.hak \
 	feed-01.hak \
+	fork-01.hak \
+	fork-02.hak \
 	fun-01.hak \
 	hnd-01.hak \
 	hnd-02.hak \
 	hnd-03.hak \
 	insta-01.hak \
 	insta-02.hak \
+	mutex-01.hak \
+	mutex-02.hak \
 	mux-01.hak \
 	mux-02.hak \
+	mux-03.hak \
 	prim-01.hak \
 	proc-01.hak \
 	proclib-01.hak \
@@ -31,6 +37,7 @@ check_SCRIPTS = \
 	sysproc-01.hak \
 	sysproc-02.hak \
 	tick-01.hak \
+	try-01.hak \
 	va-01.hak \
 	var-01.hak \
 	var-02.hak \
@@ -50,11 +57,13 @@ check_ERRORS = \
 check_PROGRAMS = \
 	t-001 \
 	t-002 \
-	t-003
+	t-003 \
+	t-004
 
 t_001_SOURCES = t-001.c tap.h
 t_002_SOURCES = t-002.c tap.h
 t_003_SOURCES = t-003.c tap.h
+t_004_SOURCES = t-004.c tap.h
 
 ##noinst_SCRIPTS = $(check_SCRIPTS)
 EXTRA_DIST = $(check_SCRIPTS) $(check_ERRORS)

t/Makefile.in

@@ -89,7 +89,8 @@ PRE_UNINSTALL = :
 POST_UNINSTALL = :
 build_triplet = @build@
 host_triplet = @host@
-check_PROGRAMS = t-001$(EXEEXT) t-002$(EXEEXT) t-003$(EXEEXT)
+check_PROGRAMS = t-001$(EXEEXT) t-002$(EXEEXT) t-003$(EXEEXT) \
+	t-004$(EXEEXT)
 subdir = t
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
 am__aclocal_m4_deps = $(top_srcdir)/m4/ax_check_sign.m4 \
@@ -120,6 +121,10 @@ am_t_003_OBJECTS = t-003.$(OBJEXT)
 t_003_OBJECTS = $(am_t_003_OBJECTS)
 t_003_LDADD = $(LDADD)
 t_003_DEPENDENCIES = ../lib/libhak.la
+am_t_004_OBJECTS = t-004.$(OBJEXT)
+t_004_OBJECTS = $(am_t_004_OBJECTS)
+t_004_LDADD = $(LDADD)
+t_004_DEPENDENCIES = ../lib/libhak.la
 AM_V_P = $(am__v_P_@AM_V@)
 am__v_P_ = $(am__v_P_@AM_DEFAULT_V@)
 am__v_P_0 = false
@@ -136,7 +141,7 @@ DEFAULT_INCLUDES =
 depcomp = $(SHELL) $(top_srcdir)/ac/depcomp
 am__maybe_remake_depfiles = depfiles
 am__depfiles_remade = ./$(DEPDIR)/t-001.Po ./$(DEPDIR)/t-002.Po \
-	./$(DEPDIR)/t-003.Po
+	./$(DEPDIR)/t-003.Po ./$(DEPDIR)/t-004.Po
 am__mv = mv -f
 COMPILE = $(CC) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) \
 	$(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS)
@@ -156,8 +161,10 @@ AM_V_CCLD = $(am__v_CCLD_@AM_V@)
 am__v_CCLD_ = $(am__v_CCLD_@AM_DEFAULT_V@)
 am__v_CCLD_0 = @echo "  CCLD    " $@;
 am__v_CCLD_1 = 
-SOURCES = $(t_001_SOURCES) $(t_002_SOURCES) $(t_003_SOURCES)
+SOURCES = $(t_001_SOURCES) $(t_002_SOURCES) $(t_003_SOURCES) \
-DIST_SOURCES = $(t_001_SOURCES) $(t_002_SOURCES) $(t_003_SOURCES)
+	$(t_004_SOURCES)
+DIST_SOURCES = $(t_001_SOURCES) $(t_002_SOURCES) $(t_003_SOURCES) \
+	$(t_004_SOURCES)
 am__can_run_installinfo = \
   case $$AM_UPDATE_INFO_DIR in \
     n|no|NO) false;; \
@@ -543,7 +550,8 @@ AM_CPPFLAGS = \
 	-I$(abs_builddir)/../lib \
 	-I$(abs_srcdir) \
 	-I$(abs_srcdir)/../lib \
-	-I$(includedir)
+	-I$(includedir) \
+	-DHAK_TEST_MODLIBDIRS='"@abs_top_builddir@/mod:@abs_top_builddir@/mod/.libs"'
 
 LDADD = ../lib/libhak.la
 check_SCRIPTS = \
@@ -551,14 +559,19 @@ check_SCRIPTS = \
 	cons-01.hak \
 	dic-01.hak \
 	feed-01.hak \
+	fork-01.hak \
+	fork-02.hak \
 	fun-01.hak \
 	hnd-01.hak \
 	hnd-02.hak \
 	hnd-03.hak \
 	insta-01.hak \
 	insta-02.hak \
+	mutex-01.hak \
+	mutex-02.hak \
 	mux-01.hak \
 	mux-02.hak \
+	mux-03.hak \
 	prim-01.hak \
 	proc-01.hak \
 	proclib-01.hak \
@@ -569,6 +582,7 @@ check_SCRIPTS = \
 	sysproc-01.hak \
 	sysproc-02.hak \
 	tick-01.hak \
+	try-01.hak \
 	va-01.hak \
 	var-01.hak \
 	var-02.hak \
@@ -588,6 +602,7 @@ check_ERRORS = \
 t_001_SOURCES = t-001.c tap.h
 t_002_SOURCES = t-002.c tap.h
 t_003_SOURCES = t-003.c tap.h
+t_004_SOURCES = t-004.c tap.h
 EXTRA_DIST = $(check_SCRIPTS) $(check_ERRORS)
 TESTS = $(check_PROGRAMS) $(check_SCRIPTS) $(check_ERRORS)
 TEST_EXTENSIONS = .hak .err
@@ -646,6 +661,10 @@ t-003$(EXEEXT): $(t_003_OBJECTS) $(t_003_DEPENDENCIES) $(EXTRA_t_003_DEPENDENCIE
 	@rm -f t-003$(EXEEXT)
 	$(AM_V_CCLD)$(LINK) $(t_003_OBJECTS) $(t_003_LDADD) $(LIBS)
 
+t-004$(EXEEXT): $(t_004_OBJECTS) $(t_004_DEPENDENCIES) $(EXTRA_t_004_DEPENDENCIES) 
+	@rm -f t-004$(EXEEXT)
+	$(AM_V_CCLD)$(LINK) $(t_004_OBJECTS) $(t_004_LDADD) $(LIBS)
+
 mostlyclean-compile:
 	-rm -f *.$(OBJEXT)
 
@@ -655,6 +674,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/t-001.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/t-002.Po@am__quote@ # am--include-marker
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/t-003.Po@am__quote@ # am--include-marker
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/t-004.Po@am__quote@ # am--include-marker
 
 $(am__depfiles_remade):
 	@$(MKDIR_P) $(@D)
@@ -931,6 +951,13 @@ t-003.log: t-003$(EXEEXT)
 	--log-file $$b.log --trs-file $$b.trs \
 	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
 	"$$tst" $(AM_TESTS_FD_REDIRECT)
+t-004.log: t-004$(EXEEXT)
+	@p='t-004$(EXEEXT)'; \
+	b='t-004'; \
+	$(am__check_pre) $(LOG_DRIVER) --test-name "$$f" \
+	--log-file $$b.log --trs-file $$b.trs \
+	$(am__common_driver_flags) $(AM_LOG_DRIVER_FLAGS) $(LOG_DRIVER_FLAGS) -- $(LOG_COMPILE) \
+	"$$tst" $(AM_TESTS_FD_REDIRECT)
 .hak.log:
 	@p='$<'; \
 	$(am__set_b); \
@@ -1041,6 +1068,7 @@ distclean: distclean-am
 	-rm -f ./$(DEPDIR)/t-001.Po
 	-rm -f ./$(DEPDIR)/t-002.Po
 	-rm -f ./$(DEPDIR)/t-003.Po
+	-rm -f ./$(DEPDIR)/t-004.Po
 	-rm -f Makefile
 distclean-am: clean-am distclean-compile distclean-generic \
 	distclean-tags
@@ -1089,6 +1117,7 @@ maintainer-clean: maintainer-clean-am
 	-rm -f ./$(DEPDIR)/t-001.Po
 	-rm -f ./$(DEPDIR)/t-002.Po
 	-rm -f ./$(DEPDIR)/t-003.Po
+	-rm -f ./$(DEPDIR)/t-004.Po
 	-rm -f Makefile
 maintainer-clean-am: distclean-am maintainer-clean-generic
 

t/fork-01.hak

@@ -0,0 +1,73 @@
+## fork must build the new process's initial context in the NEW process.
+##
+## A context normally lives on the frame stack of the process that owns it.
+## fork has to create one before the new process runs, and it used to carve it
+## out of the CALLER's frame stack instead of the callee's. Nothing goes wrong
+## while the caller is alive, so this is only observable once the caller has
+## terminated and its process object has been collected: the child is then left
+## with initial_context/current_context pointing into freed memory.
+##
+## Two things below are what make that observable, and neither is incidental:
+##
+##   - the main process forks and then simply ENDS. It does not wait for the
+##     workers. HAK_TRAIT_AWAIT_PROCS keeps the vm running the children after
+##     the main process is gone, so the creator really is dead and collected
+##     while its children are still running.
+##
+##   - each worker builds a block literal INSIDE itself and runs it. MAKE_BLOCK
+##     reifies the home context, which is the dereference that reads the freed
+##     stack context. Without a block literal the dangling pointer is merely
+##     held, not followed.
+##
+## So the test is the run itself: reaching the OK lines means the children
+## outlived their creator and still found their own contexts. Against the old
+## behaviour this segfaults instead, and run.sh reports the non-zero exit.
+##
+## [NOTE] keep this file free of anything that is not part of the above. Extra
+## phases beforehand change the heap enough that the freed memory is no longer
+## recycled under the child, and the crash stops reproducing - which is exactly
+## why this does not live at the end of t/mutex-02.hak. When HAK_ENABLE_STACK_
+## CONTEXT is undefined there are no stack contexts and no bug to trip over;
+## the file still runs clean, it just is not testing anything.
+
+$include "../src/kernel.hak"
+
+fun chk(ok msg) {
+	if ok { printf "OK: %s\n" msg } \
+	else { printf "ERROR: %s\n" msg }
+}
+
+WORKERS := 5
+SPINS   := 100
+
+mux := (Mutex:new)
+
+fun orphan() {
+	| body |
+
+	## built here, in the forked process, so MAKE_BLOCK runs against the
+	## context fork created for this process
+	body := (fun() {
+		| i |
+		i := 0
+		while (< i SPINS) {
+			i := (+ i 1)
+			core.yield        ## give the other workers a turn while holding it
+		}
+	})
+
+	mux:critical body
+	chk true "a forked process still runs after its creator is gone"
+}
+
+fun spawn() {
+	| i |
+	i := 0
+	while (< i WORKERS) {
+		core.fork orphan
+		i := (+ i 1)
+	}
+}
+
+## no wait, on purpose - see the header
+spawn

t/fork-02.hak

@@ -0,0 +1,74 @@
+## fork must not leak a frame in the CALLER's frame stack.
+##
+## A stack context is carved out of a process's frame stack by alloc_frame_slots
+## bumping that process's fsp, and it is popped again by release_stack_context
+## when the owning process returns through it. fork has to build a context for
+## the process it is creating, and it used to allocate that context out of the
+## CALLER's frame stack. The caller never returns through it, so nothing ever
+## popped it: every fork permanently consumed a frame of the forking process.
+##
+## That is the same one-line defect t/fork-01.hak covers, but it shows up as a
+## completely different symptom, so it is worth pinning separately. fork-01
+## catches the dangling context (a segfault once the parent is collected); this
+## one catches the slow exhaustion, which is what a long-lived process that
+## forks in a loop - a server accepting connections, say - would actually hit.
+## Neither symptom implies the other on inspection.
+##
+## Sizing: one leaked context is HAK_STACK_CONTEXT_NAMED_SLOTS (15) slots plus
+## the block's temporaries, and the frame stack is HAK_DFL_PROCSTK_SIZE slots
+## (8192 by default, or the HAK_MIN_FSTK_SIZE floor of 1024 under HAK_SMALL_
+## MEMORY_FOOTPRINT). So the old behaviour ran out after roughly 546 forks on a
+## default build and far sooner on a small one. 600 clears both. The count only
+## has to sit above the threshold and never needs retuning, because a correct
+## fork does not grow the caller's frame stack at all - measured flat at 5000.
+##
+## [NOTE] the loop is inside a function on purpose. The leak is charged to the
+## process running it, so that process has to stay alive across all 600 forks
+## for the frames to pile up.
+
+$include "../src/kernel.hak"
+
+fun chk(ok msg) {
+	if ok { printf "OK: %s\n" msg } \
+	else { printf "ERROR: %s\n" msg }
+}
+
+FORKS := 600
+
+forked := 0
+failed := 0
+ran    := 0
+done   := (Semaphore:new)
+
+fun noop() {
+	ran := (+ ran 1)
+	done:signal
+}
+
+## catch rather than let the overflow abort the script, so a regression is
+## reported as a failed assertion instead of an unhandled exception
+fun spawner() {
+	| i |
+	i := 0
+	while (< i FORKS) {
+		try { core.fork noop ; forked := (+ forked 1) } catch (e) { failed := (+ failed 1) }
+		i := (+ i 1)
+	}
+}
+
+fun waitall(n) {
+	| i |
+	i := 0
+	while (< i n) {
+		done:wait
+		i := (+ i 1)
+	}
+}
+
+spawner
+
+chk (= failed 0) "600 forks from one function all succeed"
+chk (= forked FORKS) "every fork answered a process"
+
+waitall forked
+chk (= ran FORKS) "all 600 forked processes actually ran"

t/hnd-03.hak

@@ -7,21 +7,21 @@ fun chk(ok msg) {
 	else { printf "ERROR: %s\n" msg }
 }
 
-iosem := (sem-new)
+iosem := (core.sem-new)
-tmo   := (sem-new)
+tmo   := (core.sem-new)
-sg    := (semgr-new)
+sg    := (core.semgr-new)
-semgr-add sg iosem
+core.semgr-add sg iosem
-semgr-add sg tmo
+core.semgr-add sg tmo
-fin   := (sem-new)
+fin   := (core.sem-new)
 
 ## returns 1 when the handle became readable, 0 when the timeout won
 fun waitin(h secs) {
 	| s |
-	sem-signal tmo secs 0
+	core.sem-signal tmo secs 0
-	sem-signal-on-input iosem h
+	core.sem-signal-on-input iosem h
-	s := (semgr-wait sg)
+	s := (core.semgr-wait sg)
-	sem-unsignal iosem
+	core.sem-unsignal iosem
-	sem-unsignal tmo
+	core.sem-unsignal tmo
 	if (eqv? s tmo) { return 0 } \
 	else { return 1 }
 }
@@ -46,12 +46,12 @@ fun reader() {
 		n := (sys.read r buf)
 		if (>= n 0) {
 			got := n
-			sem-signal fin
+			core.sem-signal fin
 			return 0
 		}
 		if (= (waitin r 5) 0) {
 			got := -1
-			sem-signal fin
+			core.sem-signal fin
 			return 0
 		}
 	}
@@ -63,7 +63,7 @@ fun writer() {
 	## so these ticks only happen if the VM is still scheduling
 	while (< ticks 4) {
 		ticks := (+ ticks 1)
-		yield
+		core.yield
 	}
 	wb := (core.basicNew ByteArray 2)
 	core.basicAtPut wb 0 120
@@ -71,9 +71,9 @@ fun writer() {
 	sys.write w wb
 }
 
-fork reader
+core.fork reader
-fork writer
+core.fork writer
-sem-wait fin
+core.sem-wait fin
 
 chk (= ticks 4) "other coprocesses ran while the reader was blocked"
 chk (= got 2) "the reader woke and read the data"

t/hnd-5001.err

@@ -2,13 +2,13 @@
 ## stops hak code naming a descriptor it never opened - including hak's own
 ## multiplexer, signal and io-thread descriptors, and anything the host
 ## application that embeds hak holds open.
-s := (sem-new)
+s := (core.sem-new)
-sem-signal-on-input s 0 ##ERROR: system handle 0
+core.sem-signal-on-input s 0 ##ERROR: system handle 0
 
 ---
 
-s := (sem-new)
+s := (core.sem-new)
-sem-signal-on-input s 4 ##ERROR: system handle 4
+core.sem-signal-on-input s 4 ##ERROR: system handle 4
 
 ---
 
@@ -24,8 +24,8 @@ sys.read r (core.basicNew ByteArray 4) ##ERROR: system handle 0
 ## a regular file is never accepted by the multiplexer: epoll refuses one
 ## outright, and poll() would report it permanently ready
 f := (sys.open "/etc/passwd" "r")
-s := (sem-new)
+s := (core.sem-new)
-sem-signal-on-input s f ##ERROR: not of an acceptable kind
+core.sem-signal-on-input s f ##ERROR: not of an acceptable kind
 
 ---
 

t/insta-01.hak

@@ -56,7 +56,7 @@ a := (b:get-a)
 if (a != 4) {printf "ERROR: a must be 4\n" } \
 else { printf "OK %d\n" a }
 
-c := (object-new A)
+c := (core.object-new A)
 a := (c:get-a)
 if (a != nil) {printf "ERROR: a must be nil\n" } \
 else { printf "OK %O\n" a }

t/mutex-01.hak

@@ -0,0 +1,95 @@
+## a semaphore used as a mutex must give mutual exclusion across coprocesses.
+##
+## Semaphore:forMutex is (core.sem-new 1) - a counting semaphore that starts at
+## one, so the first waiter takes it and every other one blocks until the
+## holder signals. What makes this worth a test is that the holder gives up the
+## CPU inside the critical section: core.yield lets the other processes run
+## while the lock is held, which is exactly the window a broken mutex would
+## leak through.
+##
+## Both phases run the same worker. The only difference is the semaphore's
+## initial count, so a failure cannot be blamed on the two paths differing:
+##
+##   count 4 -> four processes may hold it at once, so the overlap counter
+##              must actually see them overlapping. this is the control: if it
+##              reported 1, the workers would not be interleaving at all and
+##              the mutex phase below would pass for the wrong reason.
+##   count 1 -> a mutex. the overlap counter must never exceed one.
+##
+## [NOTE] the spin counts are deliberately small - enough interleaving to
+## expose an overlap, without making the test slow. What matters is that the
+## holder yields at all, not how often.
+
+$include "../src/kernel.hak"
+
+fun chk(ok msg) {
+	if ok { printf "OK: %s\n" msg } \
+	else { printf "ERROR: %s\n" msg }
+}
+
+WORKERS := 4
+SPINS   := 20
+
+inside := 0   ## processes inside the critical section right now
+maxin  := 0   ## high-water mark of the above
+rounds := 0   ## completed critical sections
+done   := (Semaphore:new)
+
+fun worker(lock n) {
+	| i |
+	lock:wait                       ## lock
+
+	inside := (+ inside 1)
+	if (> inside maxin) { maxin := inside }
+
+	## hold the lock while yielding, so any other process that can enter will
+	i := 0
+	while (< i n) {
+		i := (+ i 1)
+		core.yield
+	}
+
+	inside := (- inside 1)
+	rounds := (+ rounds 1)
+	lock:signal                     ## unlock
+	done:signal
+}
+
+fun waitall(n) {
+	| i |
+	i := 0
+	while (< i n) {
+		done:wait
+		i := (+ i 1)
+	}
+}
+
+fun spawn(lock) {
+	| i |
+	i := 0
+	while (< i WORKERS) {
+		core.fork worker lock SPINS
+		i := (+ i 1)
+	}
+	waitall WORKERS
+}
+
+## --- control: a count of WORKERS lets everyone in at once ---
+inside := 0
+maxin  := 0
+rounds := 0
+spawn (core.sem-new WORKERS)
+
+chk (= rounds WORKERS) "every process finishes when the semaphore admits them all"
+chk (= inside 0) "the occupancy counter is balanced afterwards"
+chk (> maxin 1) "the processes really do interleave, so an overlap is detectable"
+
+## --- the mutex proper ---
+inside := 0
+maxin  := 0
+rounds := 0
+spawn (Semaphore:forMutex)
+
+chk (= rounds WORKERS) "every process finishes through the mutex too"
+chk (= inside 0) "the occupancy counter is balanced afterwards"
+chk (= maxin 1) "only one process is ever inside the critical section"

t/mutex-02.hak

@@ -0,0 +1,124 @@
+## the Mutex class.
+##
+## t/mutex-01.hak covers mutual exclusion over a raw counting semaphore, with
+## the lock taken and released by hand. This one goes through Mutex:critical,
+## which adds:
+##
+##   - the critical section is a block literal built INSIDE a forked process,
+##     so each worker runs MAKE_BLOCK against its own context rather than
+##     sharing one made by the parent.
+##
+##   - a throw out of the critical section must still release the lock, since
+##     Mutex:critical catches, unlocks, and rethrows.
+##
+## Every phase here waits for its workers, so the parent outlives them all.
+## That deliberately keeps this file away from the fork stack-context lifetime
+## question, which needs the parent to die first and is tested on its own in
+## t/fork-01.hak.
+##
+## [NOTE] reentrancy (the same process calling critical again while holding it)
+## is deliberately not exercised here - see the comment at the bottom.
+
+$include "../src/kernel.hak"
+
+fun chk(ok msg) {
+	if ok { printf "OK: %s\n" msg } \
+	else { printf "ERROR: %s\n" msg }
+}
+
+WORKERS := 5
+SPINS   := 20
+
+inside := 0   ## processes inside the critical section right now
+maxin  := 0   ## high-water mark of the above
+rounds := 0   ## completed critical sections
+done   := (Semaphore:new)
+
+## the body is built inside the forked process, so every worker runs MAKE_BLOCK
+## against its own context - the path that used to reference the parent's.
+fun worker(m locked) {
+	| body |
+
+	body := (fun() {
+		| i |
+		inside := (+ inside 1)
+		if (> inside maxin) { maxin := inside }
+		i := 0
+		while (< i SPINS) {
+			i := (+ i 1)
+			core.yield
+		}
+		inside := (- inside 1)
+		rounds := (+ rounds 1)
+	})
+
+	if locked { m:critical body } else { body }
+	done:signal
+}
+
+fun waitall(n) {
+	| i |
+	i := 0
+	while (< i n) {
+		done:wait
+		i := (+ i 1)
+	}
+}
+
+fun spawn(m locked) {
+	| i |
+	i := 0
+	while (< i WORKERS) {
+		core.fork worker m locked
+		i := (+ i 1)
+	}
+	waitall WORKERS
+}
+
+mux := (Mutex:new)
+
+## --- control: same workers, same block, no locking ---
+inside := 0
+maxin  := 0
+rounds := 0
+spawn mux false
+
+chk (= rounds WORKERS) "every unlocked process finishes"
+chk (= inside 0) "the occupancy counter is balanced afterwards"
+chk (> maxin 1) "the processes really do interleave, so an overlap is detectable"
+
+## --- the same thing through Mutex:critical ---
+inside := 0
+maxin  := 0
+rounds := 0
+spawn mux true
+
+chk (= rounds WORKERS) "every process finishes through Mutex:critical too"
+chk (= inside 0) "the occupancy counter is balanced afterwards"
+chk (= maxin 1) "only one process is ever inside the critical section"
+
+## --- a throw out of the critical section unlocks and propagates ---
+caught := 0
+try { mux:critical (fun() { throw 5 }) } catch (e) { caught := e }
+chk (= caught 5) "an exception raised inside a critical section propagates"
+
+reused := 0
+mux:critical (fun() { reused := 1 })
+chk (= reused 1) "the mutex is still usable after an exception unwound it"
+
+## --- each process has its own identity ---
+main_id := ((core.active-process):id)
+other_id := 0
+fun idjob() { other_id := ((core.active-process):id) ; done:signal }
+core.fork idjob
+waitall 1
+chk (>= main_id 0) "the main process has an id"
+chk (> other_id main_id) "a forked process gets a later id"
+chk (nqv? main_id other_id) "a forked process has an id of its own"
+
+## [NOTE] Mutex:critical is reentrant by design - it tracks _owner and
+## _nest_count so the holder may re-enter - but the nested path returns from
+## inside the 'if' without undoing its own increment, so _nest_count never
+## falls back to 0 and the semaphore is never signalled. A process that nests
+## once holds the mutex forever. No case below exercises nesting for that
+## reason; add one when the counting is fixed.

t/mux-01.hak

@@ -16,20 +16,20 @@ fun chk(ok msg) {
 	else { printf "ERROR: %s\n" msg }
 }
 
-iosem := (sem-new)
+iosem := (core.sem-new)
-tmo   := (sem-new)
+tmo   := (core.sem-new)
-sg    := (semgr-new)
+sg    := (core.semgr-new)
-semgr-add sg iosem
+core.semgr-add sg iosem
-semgr-add sg tmo
+core.semgr-add sg tmo
 
 ## 1 when the handle became readable, 0 when the timer won instead
 fun waitin(h secs) {
 	| s |
-	sem-signal tmo secs 0
+	core.sem-signal tmo secs 0
-	sem-signal-on-input iosem h
+	core.sem-signal-on-input iosem h
-	s := (semgr-wait sg)
+	s := (core.semgr-wait sg)
-	sem-unsignal iosem
+	core.sem-unsignal iosem
-	sem-unsignal tmo
+	core.sem-unsignal tmo
 	if (eqv? s tmo) { return 0 } else { return 1 }
 }
 

t/mux-02.hak

@@ -15,15 +15,15 @@ fun chk(ok msg) {
 	else { printf "ERROR: %s\n" msg }
 }
 
-sg  := (semgr-new)
+sg  := (core.semgr-new)
-sa  := (sem-new)
+sa  := (core.sem-new)
-sb  := (sem-new)
+sb  := (core.sem-new)
-sc  := (sem-new)
+sc  := (core.sem-new)
-tmo := (sem-new)
+tmo := (core.sem-new)
-semgr-add sg sa
+core.semgr-add sg sa
-semgr-add sg sb
+core.semgr-add sg sb
-semgr-add sg sc
+core.semgr-add sg sc
-semgr-add sg tmo
+core.semgr-add sg tmo
 
 ## staggered so the completion order is a, then b, then c
 pa := (sys.popen "sleep 0.2; echo aaa" "r")
@@ -35,14 +35,14 @@ hb := (core.basicAt pb 2)
 hc := (core.basicAt pc 2)
 
 ## all three bound at the same time - three live tuple entries
-sem-signal-on-input sa ha
+core.sem-signal-on-input sa ha
-sem-signal-on-input sb hb
+core.sem-signal-on-input sb hb
-sem-signal-on-input sc hc
+core.sem-signal-on-input sc hc
-sem-signal tmo 9 0
+core.sem-signal tmo 9 0
 
 fun expect(want h name) {
 	| s buf got |
-	s := (semgr-wait sg)
+	s := (core.semgr-wait sg)
 	chk (eqv? s want) name
 	buf := (core.basicNew ByteArray 8)
 	got := (sys.read h buf)
@@ -52,15 +52,15 @@ fun expect(want h name) {
 ## unbinding sa frees the first slot, so the last entry migrates into it and
 ## sb/sc must still resolve to their own handles afterwards
 expect sa ha "the first child woke its own semaphore"
-sem-unsignal sa
+core.sem-unsignal sa
 
 expect sb hb "the second child woke its own semaphore after compaction"
-sem-unsignal sb
+core.sem-unsignal sb
 
 expect sc hc "the third child woke its own semaphore after compaction"
-sem-unsignal sc
+core.sem-unsignal sc
 
-sem-unsignal tmo
+core.sem-unsignal tmo
 sys.pclose (core.basicAt pa 0)
 sys.pclose (core.basicAt pb 0)
 sys.pclose (core.basicAt pc 0)

t/mux-03.hak

@@ -0,0 +1,67 @@
+## both directions bound to one descriptor, then one of them dropped
+##
+## Binding an input and an output semaphore to the same handle gives the VM a
+## tuple with two directions. Unbinding one of them leaves the other in place,
+## so delete_sem_from_sem_io_tuple() modifies the registration rather than
+## removing it - vm_muxmod() instead of vm_muxdel(). Nothing else in the suite
+## takes that path, so the per-direction event purge behind it is otherwise
+## never executed.
+##
+## A pipe's write end is used because it is always writable, so the output
+## semaphore has something to report; the input side is registered but never
+## fires, which is fine - what matters is that both directions are registered.
+
+fun chk(ok msg) {
+	if ok { printf "OK: %s\n" msg } \
+	else { printf "ERROR: %s\n" msg }
+}
+
+sg   := (core.semgr-new)
+isem := (core.sem-new)
+osem := (core.sem-new)
+tmo  := (core.sem-new)
+core.semgr-add sg isem
+core.semgr-add sg osem
+core.semgr-add sg tmo
+
+p := (sys.pipe)
+r := (core.basicAt p 0)
+w := (core.basicAt p 1)
+
+## one descriptor, two directions - the tuple now carries both
+core.sem-signal-on-input isem w
+core.sem-signal-on-output osem w
+
+## drop only the input direction. the output registration must survive, and so
+## must any event already reported for it
+core.sem-unsignal isem
+
+core.sem-signal tmo 5 0
+s := (core.semgr-wait sg)
+chk (eqv? s osem) "the surviving direction still reports after a partial unbind"
+core.sem-unsignal tmo
+
+## put the input direction back while the output one is still registered. this
+## is the add branch of the modify path - the mirror of the drop above - and it
+## has to leave the output registration alone.
+core.sem-signal-on-input isem w
+
+## now drop the output direction instead, keeping input. a write end is never
+## readable, so with input alone nothing can report and the timer must win. if
+## the modify path had left the output registration behind, its writability
+## would be reported here and the timer would lose.
+core.sem-unsignal osem
+core.sem-signal tmo 0 300000000
+s := (core.semgr-wait sg)
+chk (eqv? s tmo) "the dropped direction stops reporting after a partial unbind"
+core.sem-unsignal tmo
+
+## and the full unbind from that state really removes the registration
+core.sem-unsignal isem
+core.sem-signal tmo 0 300000000
+s := (core.semgr-wait sg)
+chk (eqv? s tmo) "nothing reports once both directions are unbound"
+core.sem-unsignal tmo
+
+sys.close r
+sys.close w

t/proc-01.hak

@@ -8,11 +8,11 @@ fun loop1() {
 	while (< k 100) {
 		printf "loop1 => %d\n" k
 		k := (+ k 2)
-		yield
+		core.yield
 	}
 
 	z1 := k
-	sem-signal s1
+	core.sem-signal s1
 }
 
 fun loop2() {
@@ -22,26 +22,26 @@ fun loop2() {
 	while (< k 100) {
 		printf "loop2 => %d\n" k
 		k := (+ k 2)
-		yield
+		core.yield
 	}
 
 	z2 := k
-	sem-signal s2
+	core.sem-signal s2
 }
 
-s1 := (sem-new)
+s1 := (core.sem-new)
-s2 := (sem-new)
+s2 := (core.sem-new)
 
-p1 := (fork loop1)
+p1 := (core.fork loop1)
-p2 := (fork loop2)
+p2 := (core.fork loop2)
 
-##suspend p1
+##core.suspend p1
-##suspend p2
+##core.suspend p2
-##resume p1
+##core.resume p1
-##resume p2
+##core.resume p2
 
-sem-wait s1
+core.sem-wait s1
-sem-wait s2
+core.sem-wait s2
 
 if (== z1 101) { printf "OK: z1 is %d\n" z1 } \
 else { printf "ERROR: z1 is not 101 - %d\n" z1 }

t/proclib-01.hak

@@ -22,10 +22,10 @@ ticks := 0
 fun ticker() {
 	while (< ticks 5) {
 		ticks := (+ ticks 1)
-		yield
+		core.yield
 	}
 }
-fork ticker
+core.fork ticker
 
 order := (core.basicNew Array 3)
 n := 0

t/sig-01.hak

@@ -27,23 +27,23 @@ sys.close (core.basicAt q 0)
 sys.close (core.basicAt q 1)
 
 ## --- catch and uncatch are idempotent ---
-chk (= (system-catch-sig sys.SIGUSR1) sys.SIGUSR1) "system-catch-sig returns the signal number"
+chk (= (sys.sig-catch sys.SIGUSR1) sys.SIGUSR1) "sys.sig-catch returns the signal number"
-chk (= (system-catch-sig sys.SIGUSR1) sys.SIGUSR1) "catching an already caught signal is fine"
+chk (= (sys.sig-catch sys.SIGUSR1) sys.SIGUSR1) "catching an already caught signal is fine"
-chk (= (system-uncatch-sig sys.SIGUSR1) sys.SIGUSR1) "system-uncatch-sig returns the signal number"
+chk (= (sys.sig-uncatch sys.SIGUSR1) sys.SIGUSR1) "sys.sig-uncatch returns the signal number"
-chk (= (system-uncatch-sig sys.SIGUSR1) sys.SIGUSR1) "uncatching an uncaught signal is fine"
+chk (= (sys.sig-uncatch sys.SIGUSR1) sys.SIGUSR1) "uncatching an uncaught signal is fine"
 
 ## --- a real signal reaches hak code, without stalling the coprocesses ---
 ## SIGCHLD is used because a child exiting is something this test can arrange
 ## on its own, with no outside help.
-system-catch-sig sys.SIGCHLD
+sys.sig-catch sys.SIGCHLD
 
-h     := (system-get-sigfd)
+h     := (sys.sig-getfd)
-s     := (sem-new)
+s     := (core.sem-new)
-tmo   := (sem-new)
+tmo   := (core.sem-new)
-sg    := (semgr-new)
+sg    := (core.semgr-new)
-semgr-add sg s
+core.semgr-add sg s
-semgr-add sg tmo
+core.semgr-add sg tmo
-fin   := (sem-new)
+fin   := (core.sem-new)
 ticks := 0
 signo := -1
 
@@ -52,14 +52,14 @@ proc := (core.basicAt pr 0)
 
 fun waiter() {
 	| w |
-	sem-signal tmo 20 0
+	core.sem-signal tmo 20 0
-	sem-signal-on-input s h
+	core.sem-signal-on-input s h
-	w := (semgr-wait sg)
+	w := (core.semgr-wait sg)
-	sem-unsignal s
+	core.sem-unsignal s
-	sem-unsignal tmo
+	core.sem-unsignal tmo
 	if (eqv? w tmo) { signo := -2 } \
-	else { signo := (system-get-sig) }
+	else { signo := (sys.sig-get) }
-	sem-signal fin
+	core.sem-signal fin
 	return 0
 }
 
@@ -67,16 +67,16 @@ fun ticker() {
 	## the waiter is parked on the signal descriptor by now
 	while (< ticks 4) {
 		ticks := (+ ticks 1)
-		yield
+		core.yield
 	}
 }
 
-fork waiter
+core.fork waiter
-fork ticker
+core.fork ticker
-sem-wait fin
+core.sem-wait fin
 
 chk (= ticks 4) "coprocesses ran while a coprocess waited on a signal"
 chk (= signo sys.SIGCHLD) "the signal number came through the signal descriptor"
 chk (= (sys.pwait proc) 4) "and the child's exit status is readable"
 sys.pclose proc
-system-uncatch-sig sys.SIGCHLD
+sys.sig-uncatch sys.SIGCHLD

t/sig-02.hak

@@ -54,8 +54,8 @@ chk (== sys.SIGTERM 15) "SIGTERM is 15"
 
 ## and the constants behave: a routable one can be caught, an unroutable one
 ## cannot, whatever the numbers happen to be here
-chk (== (system-catch-sig sys.SIGUSR1) sys.SIGUSR1) "SIGUSR1 is catchable"
+chk (== (sys.sig-catch sys.SIGUSR1) sys.SIGUSR1) "SIGUSR1 is catchable"
-chk (== (system-uncatch-sig sys.SIGUSR1) sys.SIGUSR1) "SIGUSR1 is uncatchable again"
+chk (== (sys.sig-uncatch sys.SIGUSR1) sys.SIGUSR1) "SIGUSR1 is uncatchable again"
 raised := false
-try { system-catch-sig sys.SIGKILL } catch (e) { raised := true }
+try { sys.sig-catch sys.SIGKILL } catch (e) { raised := true }
 chk raised "SIGKILL is refused"

t/sig-5001.err

@@ -1,41 +1,41 @@
 ## signals that cannot be caught
-system-catch-sig sys.SIGKILL ##ERROR: not routable
+sys.sig-catch sys.SIGKILL ##ERROR: not routable
 
 ---
 
-system-catch-sig sys.SIGSTOP ##ERROR: not routable
+sys.sig-catch sys.SIGSTOP ##ERROR: not routable
 
 ---
 
 ## signals that indicate a crash: turning one into a byte on a pipe and
 ## carrying on would hide the fault rather than report it
-system-catch-sig sys.SIGSEGV ##ERROR: not routable
+sys.sig-catch sys.SIGSEGV ##ERROR: not routable
 
 ---
 
-system-catch-sig sys.SIGBUS ##ERROR: not routable
+sys.sig-catch sys.SIGBUS ##ERROR: not routable
 
 ---
 
-system-catch-sig sys.SIGFPE ##ERROR: not routable
+sys.sig-catch sys.SIGFPE ##ERROR: not routable
 
 ---
 
-system-catch-sig sys.SIGILL ##ERROR: not routable
+sys.sig-catch sys.SIGILL ##ERROR: not routable
 
 ---
 
 ## the timer signal hak itself uses to switch processes
-system-catch-sig sys.SIGVTALRM ##ERROR: not routable
+sys.sig-catch sys.SIGVTALRM ##ERROR: not routable
 
 ---
 
-system-catch-sig 0 ##ERROR: 0 not routable
+sys.sig-catch 0 ##ERROR: 0 not routable
 
 ---
 
-system-catch-sig 9999 ##ERROR: 9999 not routable
+sys.sig-catch 9999 ##ERROR: 9999 not routable
 
 ---
 
-system-catch-sig "two" ##ERROR: number not a small integer
+sys.sig-catch "two" ##ERROR: number not a small integer

t/sysproc-01.hak

@@ -5,19 +5,19 @@ fun chk(ok msg) {
 	else { printf "ERROR: %s\n" msg }
 }
 
-iosem := (sem-new)
+iosem := (core.sem-new)
-tmo   := (sem-new)
+tmo   := (core.sem-new)
-sg    := (semgr-new)
+sg    := (core.semgr-new)
-semgr-add sg iosem
+core.semgr-add sg iosem
-semgr-add sg tmo
+core.semgr-add sg tmo
 
 fun waitin(h secs) {
 	| s |
-	sem-signal tmo secs 0
+	core.sem-signal tmo secs 0
-	sem-signal-on-input iosem h
+	core.sem-signal-on-input iosem h
-	s := (semgr-wait sg)
+	s := (core.semgr-wait sg)
-	sem-unsignal iosem
+	core.sem-unsignal iosem
-	sem-unsignal tmo
+	core.sem-unsignal tmo
 	if (eqv? s tmo) { return 0 } else { return 1 }
 }
 
@@ -38,9 +38,9 @@ fun reap(proc) {
 	while (< k 300) {
 		n := (sys.pwait proc)
 		if (not (= n 256)) { return n }
-		sem-signal tmo 0 20000000
+		core.sem-signal tmo 0 20000000
-		semgr-wait sg
+		core.semgr-wait sg
-		sem-unsignal tmo
+		core.sem-unsignal tmo
 		k := (+ k 1)
 	}
 	return 256

t/sysproc-02.hak

@@ -9,12 +9,12 @@ fun chk(ok msg) {
 	else { printf "ERROR: %s\n" msg }
 }
 
-iosem := (sem-new)
+iosem := (core.sem-new)
-tmo   := (sem-new)
+tmo   := (core.sem-new)
-sg    := (semgr-new)
+sg    := (core.semgr-new)
-semgr-add sg iosem
+core.semgr-add sg iosem
-semgr-add sg tmo
+core.semgr-add sg tmo
-fin   := (sem-new)
+fin   := (core.sem-new)
 
 p    := (sys.popen "sleep 1; exit 5" "r")
 proc := (core.basicAt p 0)
@@ -30,14 +30,14 @@ else {
 
 	fun waiter() {
 		| s |
-		sem-signal tmo 20 0
+		core.sem-signal tmo 20 0
-		sem-signal-on-input iosem xh
+		core.sem-signal-on-input iosem xh
-		s := (semgr-wait sg)
+		s := (core.semgr-wait sg)
-		sem-unsignal iosem
+		core.sem-unsignal iosem
-		sem-unsignal tmo
+		core.sem-unsignal tmo
 		if (eqv? s tmo) { status := -1 } \
 		else { status := (sys.pwait proc) }
-		sem-signal fin
+		core.sem-signal fin
 		return 0
 	}
 
@@ -46,14 +46,14 @@ else {
 		## happen if the VM went on scheduling instead of blocking
 		while (< ticks 4) {
 			ticks := (+ ticks 1)
-			yield
+			core.yield
 		}
 	}
 
 	chk (integer? xh) "sys.popen hands back an exit handle"
-	fork waiter
+	core.fork waiter
-	fork ticker
+	core.fork ticker
-	sem-wait fin
+	core.sem-wait fin
 
 	chk (= ticks 4) "other coprocesses ran while the child was alive"
 	chk (= status 5) "the exit handle woke the waiter and the status was read"

t/t-002.c

@@ -199,12 +199,6 @@ static void termreq_round_trips (void)
 	void* during[NTERMREQ];
 	void* after[NTERMREQ];
 	int i;
-
-	for (i = 0; i < NTERMREQ; i++)
-	{
-		if (disposition_of(TERMREQ[i], &before[i]) <= -1) return; /* no sigaction */
-	}
-
 #if defined(SIGPIPE)
 	/* SIGPIPE is deliberately NOT in the set above. It is not a termination
 	 * request - it is the opposite, a measure against being terminated - and
@@ -213,7 +207,16 @@ static void termreq_round_trips (void)
 	 * So termreq must leave it exactly alone. */
 	void* pipe_before;
 	void* pipe_during;
-	int pipe_probed = (disposition_of(SIGPIPE, &pipe_before) >= 0);
+	int pipe_probed;
+#endif
+
+	for (i = 0; i < NTERMREQ; i++)
+	{
+		if (disposition_of(TERMREQ[i], &before[i]) <= -1) return; /* no sigaction */
+	}
+
+#if defined(SIGPIPE)
+	pipe_probed = (disposition_of(SIGPIPE, &pipe_before) >= 0);
 #endif
 
 	hak_catch_termreq();

t/t-003.c

@@ -80,12 +80,12 @@ static void state_contract (void)
 
 static const char SRC[] =
 	"flag := 0\n"
-	"s := (sem-new)\n"
+	"s := (core.sem-new)\n"
-	"fun setter() { flag := 1 ; sem-signal s }\n"
+	"fun setter() { flag := 1 ; core.sem-signal s }\n"
-	"p := (fork setter)\n"
+	"p := (core.fork setter)\n"
 	"i := 0\n"
 	"while (< i 300000) { if (== flag 1) { break } ; i := (+ i 1) }\n"
-	"sem-wait s\n"
+	"core.sem-wait s\n"
 	"r := i\n";
 
 static hak_oow_t bc_seen = 0;
@@ -105,6 +105,22 @@ static int on_cnode (hak_t* hak, hak_cnode_t* obj)
 	return hak_compile(hak, obj, 0);
 }
 
+/* The script below reaches the process and semaphore primitives through the
+ * core module, which is where they are registered. A build configured with
+ * --enable-static-module links that module in and resolves it unaided, but one
+ * without it has to load the module from the build tree, and a bare
+ * hak_openstd() has nowhere to look. HAK_TEST_MODLIBDIRS comes from
+ * t/Makefile.am and names the same directories run.sh passes to the script
+ * tests via --modlibdirs. */
+static int set_modlibdirs (hak_t* hak)
+{
+#if defined(HAK_TEST_MODLIBDIRS)
+	return hak_setoption(hak, HAK_OPT_MODLIBDIRS_BCSTR, HAK_TEST_MODLIBDIRS);
+#else
+	return 0;
+#endif
+}
+
 static void preempts_a_spinner (void)
 {
 	hak_t* hak;
@@ -117,9 +133,11 @@ static void preempts_a_spinner (void)
 	OK (hak != HAK_NULL, "instantiation");
 	if (!hak) return;
 
-	hak_getoption(hak, HAK_TRAIT, &trait);
+	hak_getoption(hak, HAK_OPT_TRAIT, &trait);
 	trait |= HAK_TRAIT_AWAIT_PROCS | HAK_TRAIT_LANG_ENABLE_EOL;
-	hak_setoption(hak, HAK_TRAIT, &trait);
+	hak_setoption(hak, HAK_OPT_TRAIT, &trait);
+
+	OK (set_modlibdirs(hak) == 0, "module search path");
 
 	memset (&cb, 0, sizeof(cb));
 	cb.vm_checkbc = cb_checkbc;

t/t-004.c

@@ -0,0 +1,131 @@
+/* process stack overflow must be reported, not swallowed.
+ *
+ * HAK_STACK_PUSH() detects the overflow, sets HAK_ESTKOVRFLW and stores -1 in
+ * hak->abort_req; the interpreter loop then takes "goto oops" and answers a
+ * failure. That path is only reachable while abort_req is a signed type - when
+ * it was hak_uint8_t the -1 became 255, the "abort_req < 0" test could never
+ * be true, and the overflow fell through to the ordinary "abort_req > 0" break
+ * instead. hak_execute() then answered success and the script simply stopped
+ * running with nothing reported.
+ *
+ * This is checked here rather than in t/ as a script because neither script
+ * harness can express it: run.sh fails a test as soon as the output contains
+ * an ERROR: line, and err.sh insists the error be reported at the line its
+ * ##ERROR: marker sits on, whereas a stack overflow carries no source
+ * location and is reported at [0,0]. Only a C test can assert on the value
+ * hak_execute() answers, which is the part that regressed.
+ *
+ * The nesting depth is what drives the operand stack: evaluating
+ * (+ 1 (+ 1 ... 0)) has to hold every pending left operand at once. The
+ * process stack size is set explicitly here because there is no single
+ * default to rely on - HAK_DFL_PROCSTK_SIZE is 5000, bin/hak asks for 600,
+ * and exec.c clamps whatever it is given up to a floor of 192. */
+
+#include <hak.h>
+#include "tap.h"
+#include <string.h>
+#include <stdlib.h>
+
+/* slots per nesting level are an implementation detail, so keep a wide margin
+ * on both sides of the limit rather than probing for the exact threshold */
+#define STK_SLOTS   192
+#define DEEP_DEPTH  2000
+#define SHALLOW_DEPTH 10
+
+static int on_cnode (hak_t* hak, hak_cnode_t* obj)
+{
+	return hak_compile(hak, obj, 0);
+}
+
+/* build "x := (+ 1 (+ 1 ... 0))" nested to the given depth */
+static char* make_src (int depth)
+{
+	hak_oow_t capa;
+	char* buf;
+	char* p;
+	int i;
+
+	capa = (hak_oow_t)depth * 8 + 64;
+	buf = (char*)malloc(capa);
+	if (!buf) return HAK_NULL;
+
+	p = buf;
+	memcpy(p, "x := ", 5); p += 5;
+	for (i = 0; i < depth; i++) { memcpy(p, "(+ 1 ", 5); p += 5; }
+	*p++ = '0';
+	for (i = 0; i < depth; i++) *p++ = ')';
+	*p++ = '\n';
+	*p = '\0';
+
+	return buf;
+}
+
+/* returns 0 if the run completed, -1 if the fixture itself could not be built */
+static int run_at_depth (int depth, int expect_overflow)
+{
+	hak_t* hak;
+	hak_bitmask_t trait;
+	hak_oow_t stksize;
+	hak_oop_t retv;
+	char* src;
+	int errnum;
+	int rc = -1;
+
+	src = make_src(depth);
+	OK (src != HAK_NULL, "source built");
+	if (!src) return -1;
+
+	hak = hak_openstd(0, HAK_NULL);
+	OK (hak != HAK_NULL, "instantiation");
+	if (!hak) goto done;
+
+	hak_getoption(hak, HAK_OPT_TRAIT, &trait);
+	trait |= HAK_TRAIT_LANG_ENABLE_EOL;
+	hak_setoption(hak, HAK_OPT_TRAIT, &trait);
+
+	stksize = STK_SLOTS;
+	OK (hak_setoption(hak, HAK_OPT_PROCSTK_SIZE, &stksize) == 0, "process stack size");
+
+	OK (hak_ignite(hak, 0) == 0, "ignition");
+	OK (hak_addbuiltinprims(hak) == 0, "builtin primitives");
+	OK (hak_attachcciostdwithbcstr(hak, HAK_NULL) == 0, "source input stream");
+	OK (hak_attachudiostdwithbcstr(hak, "", "") == 0, "user data streams");
+	OK (hak_beginfeed(hak, on_cnode) == 0, "begin feed");
+	OK (hak_feedbchars(hak, src, strlen(src)) == 0, "feed the script");
+	OK (hak_endfeed(hak) == 0, "end feed");
+
+	retv = hak_execute(hak);
+	errnum = (int)hak_geterrnum(hak);
+
+	if (expect_overflow)
+	{
+		printf("# depth=%d retv=%s errnum=%d (%s)\n", depth,
+			retv? "value": "HAK_NULL", errnum,
+			retv? "-": hak_geterrbmsg(hak));
+		/* the assertion that regressed: a swallowed overflow answers a value */
+		OK (retv == HAK_NULL, "an overflowing script fails rather than answering a value");
+		OK (errnum == HAK_ESTKOVRFLW, "the failure is reported as HAK_ESTKOVRFLW");
+	}
+	else
+	{
+		if (!retv) printf("# depth=%d unexpected failure: [%d] %s\n", depth, errnum, hak_geterrbmsg(hak));
+		OK (retv != HAK_NULL, "a script within the stack limit still runs");
+	}
+
+	rc = 0;
+	hak_close(hak);
+
+done:
+	free(src);
+	return rc;
+}
+
+int main (int argc, char* argv[])
+{
+	no_plan();
+	/* the control comes first: if this one failed the deep case would pass
+	 * for the wrong reason, since any failure at all answers HAK_NULL */
+	run_at_depth(SHALLOW_DEPTH, 0);
+	run_at_depth(DEEP_DEPTH, 1);
+	return exit_status();
+}

t/tick-01.hak

@@ -21,7 +21,7 @@ fun setter() { flag := 1 }
 
 ## setter is runnable from here on, but it cannot run while this process holds
 ## the CPU - and this process never calls yield.
-p := (fork setter)
+p := (core.fork setter)
 
 i := 0
 while (< i 3000000) {
@@ -38,7 +38,7 @@ chk (== flag 1) "a process that never yields is preempted so another can run"
 ## process immediately: then setter would have run before the loop started and
 ## i would be ~0, proving nothing about preemption. One tick is 20ms, which is
 ## a great many iterations.
-chk (> i 1000) "the switch came from the ticker, not from an eager fork"
+chk (> i 1000) "the switch came from the ticker, not from an eager core.fork"
 
 ## The preempted process must be resumed, not abandoned - reaching here at all
 ## means the scheduler came back to it.

t/try-01.hak

@@ -0,0 +1,202 @@
+## Two related defects in how 'return' interacts with try/catch. Both are
+## fixed; this checks both, because each hid the other while writing the test.
+##
+## 1. compile_return() emitted TRY_EXIT/CLASS_EXIT before the return value was
+##    compiled, so the value expression ran with every enclosing handler in the
+##    function already popped - not just the innermost one. The unwinding now
+##    comes from emit_return(), after the value is on the operand stack.
+##    Only the syntactic form used to matter: try { x := (f) } caught what f
+##    threw while try { return (f) } did not, so both forms appear below.
+##
+## 2. A 'return', 'break' or 'continue' inside a catch body emitted a TRY_EXIT
+##    for the very try whose handler it sat in - but 'throw' has already
+##    unwound that frame, so the second pop drove the exception stack below its
+##    base. HAK_EXSTACK_IS_EMPTY tests 'exsp <= st', so an underflowed stack
+##    reads as empty from then on and EVERY later try in the process reported
+##    'exception not handled'. The catch body is now compiled with its try
+##    block marked in_catch, which suppresses the instruction.
+##
+##    That corruption was never visible in the function that caused it, so the
+##    assertions that actually guard it are the ones exercising a try AFTER a
+##    catch that returned, broke or continued.
+
+fun chk(ok msg) {
+	if ok { printf "OK: %s\n" msg } \
+	else { printf "ERROR: %s\n" msg }
+}
+
+fun boom() { throw 99 }
+
+## ------------------------------------------------------------------
+## 1. a throw inside a return value
+## ------------------------------------------------------------------
+
+fun c1() {
+	try { return (boom) } catch (e) { return (+ e 1) }
+}
+chk (= (c1) 100) "a throw in a return value is caught by the enclosing try"
+
+## the catch need not return for the handler to run
+seen := 0
+fun c2() {
+	try { return (boom) } catch (e) { seen := e }
+	return 7
+}
+chk (= (c2) 7) "execution resumes after the try when the catch falls through"
+chk (= seen 99) "the catch body ran"
+
+fun c3() {
+	try { return (boom) } catch (e) { }
+	return 8
+}
+chk (= (c3) 8) "an empty catch body still handles the throw"
+
+## nesting: the innermost handler wins and the outer one stays out of it.
+## the old code unwound every enclosing try, so neither fired.
+inner := 0
+outer := 0
+fun c4() {
+	try {
+		try { return (boom) } catch (e) { inner := (+ inner 1) }
+	} catch (e2) { outer := (+ outer 1) }
+	return 9
+}
+chk (= (c4) 9) "a nested try returns normally after handling"
+chk (= inner 1) "the innermost try catches"
+chk (= outer 0) "the outer try is left out of it"
+
+## across a call boundary the callee's own handler wins; the old code let the
+## throw escape to the caller's handler instead
+g_seen := 0
+h_seen := 0
+fun g() { try { return (boom) } catch (e) { g_seen := 1 ; return -1 } }
+fun h() { try { return (g) } catch (e) { h_seen := 1 ; return -2 } }
+chk (= (h) -1) "the callee handles its own throw"
+chk (= g_seen 1) "the callee's catch ran"
+chk (= h_seen 0) "the caller's catch did not"
+
+## the form that always worked must keep working
+fun c5() {
+	| v |
+	v := 0
+	try { v := (boom) } catch (e) { v := e }
+	return v
+}
+chk (= (c5) 99) "a throw in an assignment is still caught"
+
+## ------------------------------------------------------------------
+## 2. leaving a catch body by return, break or continue
+##
+## each case is followed by a fresh try: that is where an underflowed
+## exception stack shows up, never in the function that caused it.
+## ------------------------------------------------------------------
+
+## a try that must still work after the cases above, which all returned from
+## inside a catch
+fun still1() {
+	| v |
+	v := 0
+	try { v := (boom) } catch (e) { v := 21 }
+	return v
+}
+chk (= (still1) 21) "a try still works after earlier catch bodies returned"
+
+## break out of a loop from inside a catch
+bj := 0
+while (< bj 9) {
+	bj := (+ bj 1)
+	try { y := (boom) } catch (e) { break }
+}
+chk (= bj 1) "break inside a catch leaves the loop"
+
+fun still2() {
+	| v |
+	v := 0
+	try { v := (boom) } catch (e) { v := 22 }
+	return v
+}
+chk (= (still2) 22) "a try still works after a break from inside a catch"
+
+## continue to the next iteration from inside a catch
+ci := 0
+ch := 0
+while (< ci 3) {
+	ci := (+ ci 1)
+	try { z := (boom) } catch (e) { ch := (+ ch 1) ; continue }
+	ch := 100
+}
+chk (= ci 3) "continue inside a catch keeps iterating"
+chk (= ch 3) "continue inside a catch skips the rest of the loop body"
+
+fun still3() {
+	| v |
+	v := 0
+	try { v := (boom) } catch (e) { v := 23 }
+	return v
+}
+chk (= (still3) 23) "a try still works after a continue from inside a catch"
+
+## the in_catch mark must suppress only the block whose handler we are in. the
+## return below sits in the inner catch, so the inner frame is already gone,
+## but the outer try is still live and has to be unwound on the way out. a
+## frame left behind there would misdirect the next throw instead.
+fun nest2() {
+	try {
+		try { w := (boom) } catch (e) { return 11 }
+	} catch (e2) { }
+	return 12
+}
+chk (= (nest2) 11) "a return from an inner catch still unwinds the outer try"
+
+fun still4() {
+	| v |
+	v := 0
+	try { v := (boom) } catch (e) { v := 24 }
+	return v
+}
+chk (= (still4) 24) "a try still works after returning from a nested catch"
+
+## ------------------------------------------------------------------
+## 3. break and continue in a try BODY still unwind
+##
+## these share emit_ctlblk_unwind with return, and here the frame is live and
+## must be popped. a leaked frame per iteration would exhaust the exception
+## stack long before these loops finish.
+## ------------------------------------------------------------------
+
+i := 0
+n := 0
+while (< i 2000) {
+	i := (+ i 1)
+	try { if (= (mod i 2) 0) { continue } ; n := (+ n 1) } catch (e) { n := -1 }
+}
+chk (= n 1000) "continue inside a try body unwinds without leaking a handler"
+
+i := 0
+while (< i 2000) {
+	i := (+ i 1)
+	try { if (= i 7) { break } } catch (e) { }
+}
+chk (= i 7) "break inside a try body unwinds and leaves the loop"
+
+## ------------------------------------------------------------------
+## 4. a handler stays live across a whole call chain
+## ------------------------------------------------------------------
+
+hits := 0
+caught := 0
+fun rec(k) {
+	if (<= k 0) { throw 55 }
+	try { return (rec (- k 1)) } catch (e) { hits := (+ hits 1) ; caught := e ; return e }
+}
+chk (= (rec 20) 55) "recursion with a try per frame propagates the thrown value"
+chk (= caught 55) "the thrown value arrives intact"
+chk (= hits 1) "only the frame nearest the throw handles it"
+
+fun still5() {
+	| v |
+	v := 0
+	try { v := (boom) } catch (e) { v := 25 }
+	return v
+}
+chk (= (still5) 25) "a try still works after deep try-per-frame recursion"