fixed the go wrapper code further

Makefile.am

@@ -42,15 +42,18 @@ hclgo_DEPENDENCIES = hclgo.bin
 ## let the linker to move hclgo.bin to the actual target
 hclgo_LINK = mv -f hclgo.bin hclgo$(EXEEXT) || echo "FAILED TO LINK"
 
-hclgo.bin:
+hclgo.bin: lib/libhcl.la
 	cp -pf $(srcdir)/go.mod $(builddir)/go.mod >/dev/null 2>&1 || true
 	chmod u+w $(builddir)/go.mod ## with `make distcheck`, the echo's redirection to the file fails without this permission change
 	sed -r -i -e "/^[[:space:]]*replace[[:space:]]+cfg[[:space:]]*=>/d" $(builddir)/go.mod
 	echo -e "\nreplace cfg => $(abs_builddir)/go/cfg" >> $(builddir)/go.mod
 	[ -f $(srcdir)/go.sum ] && cp -pf $(srcdir)/go.sum $(builddir)/go.sum >/dev/null 2>&1 || true
+	## ---------------------------------------------------------------
+	CC=$(CC) \
 	CGO_CFLAGS="-I$(abs_srcdir)/lib -I$(abs_builddir)/lib $(CFLAGS)" \
 	CGO_LDFLAGS="-L$(abs_builddir)/lib -L$(abs_builddir)/lib/.libs -lhcl -ldl -lquadmath"  \
 	go build -C $(srcdir) -x -o $(abs_builddir)/hclgo.bin -modfile $(abs_builddir)/go.mod
+	## ---------------------------------------------------------------
 	go clean -C $(srcdir) -x -modfile $(abs_builddir)/go.mod
 	rm -rf $(builddir)/go.mod $(builddir)/go.sum
 

Makefile.in

@@ -937,12 +937,13 @@ distclean-local:
 clean-local:
 	rm -rf $(builddir)/go.mod $(builddir)/go.sum
 
-@ENABLE_HCLGO_TRUE@hclgo.bin:
+@ENABLE_HCLGO_TRUE@hclgo.bin: lib/libhcl.la
 @ENABLE_HCLGO_TRUE@	cp -pf $(srcdir)/go.mod $(builddir)/go.mod >/dev/null 2>&1 || true
 @ENABLE_HCLGO_TRUE@	chmod u+w $(builddir)/go.mod ## with `make distcheck`, the echo's redirection to the file fails without this permission change
 @ENABLE_HCLGO_TRUE@	sed -r -i -e "/^[[:space:]]*replace[[:space:]]+cfg[[:space:]]*=>/d" $(builddir)/go.mod
 @ENABLE_HCLGO_TRUE@	echo -e "\nreplace cfg => $(abs_builddir)/go/cfg" >> $(builddir)/go.mod
 @ENABLE_HCLGO_TRUE@	[ -f $(srcdir)/go.sum ] && cp -pf $(srcdir)/go.sum $(builddir)/go.sum >/dev/null 2>&1 || true
+@ENABLE_HCLGO_TRUE@	CC=$(CC) \
 @ENABLE_HCLGO_TRUE@	CGO_CFLAGS="-I$(abs_srcdir)/lib -I$(abs_builddir)/lib $(CFLAGS)" \
 @ENABLE_HCLGO_TRUE@	CGO_LDFLAGS="-L$(abs_builddir)/lib -L$(abs_builddir)/lib/.libs -lhcl -ldl -lquadmath"  \
 @ENABLE_HCLGO_TRUE@	go build -C $(srcdir) -x -o $(abs_builddir)/hclgo.bin -modfile $(abs_builddir)/go.mod

go/cb.go

@@ -80,8 +80,8 @@ func (io *IOHandleTable) slot_to_io_handle(slot int) IOHandle {
 
 var io_tab IOHandleTable = IOHandleTable{}
 
-//export go_read_handler
+//export hcl_go_read_handler
-func go_read_handler(c *C.hcl_t, cmd C.hcl_iocmd_t, arg unsafe.Pointer) C.int {
+func hcl_go_read_handler(c *C.hcl_t, cmd C.hcl_iocmd_t, arg unsafe.Pointer) C.int {
 	var (
 		g   *HCL
 		err error
@@ -154,8 +154,8 @@ func go_read_handler(c *C.hcl_t, cmd C.hcl_iocmd_t, arg unsafe.Pointer) C.int {
 	return -1
 }
 
-//export go_scan_handler
+//export hcl_go_scan_handler
-func go_scan_handler(c *C.hcl_t, cmd C.hcl_iocmd_t, arg unsafe.Pointer) C.int {
+func hcl_go_scan_handler(c *C.hcl_t, cmd C.hcl_iocmd_t, arg unsafe.Pointer) C.int {
 	var (
 		g   *HCL
 		err error
@@ -202,8 +202,8 @@ func go_scan_handler(c *C.hcl_t, cmd C.hcl_iocmd_t, arg unsafe.Pointer) C.int {
 	return -1
 }
 
-//export go_print_handler
+//export hcl_go_print_handler
-func go_print_handler(c *C.hcl_t, cmd C.hcl_iocmd_t, arg unsafe.Pointer) C.int {
+func hcl_go_print_handler(c *C.hcl_t, cmd C.hcl_iocmd_t, arg unsafe.Pointer) C.int {
 	var (
 		g   *HCL
 		err error

go/hcl.go

@@ -3,6 +3,20 @@ package hcl
 /*
 #include <hcl.h>
 #include <hcl-utl.h>
+
+extern int hcl_go_read_handler (hcl_t hcl, hcl_iocmd_t cmd, void* arg);
+extern int hcl_go_scan_handler (hcl_t hcl, hcl_iocmd_t cmd, void* arg);
+extern int hcl_go_print_handler (hcl_t hcl, hcl_iocmd_t cmd, void* arg);
+
+int hcl_read_handler_for_go (hcl_t hcl, hcl_iocmd_t cmd, void* arg) {
+    return hcl_go_read_handler(hcl, cmd, arg);
+}
+int hcl_scan_handler_for_go (hcl_t hcl, hcl_iocmd_t cmd, void* arg) {
+    return hcl_go_scan_handler(hcl, cmd, arg);
+}
+int hcl_print_handler_for_go (hcl_t hcl, hcl_iocmd_t cmd, void* arg) {
+    return hcl_go_print_handler(hcl, cmd, arg);
+}
 */
 import "C"
 
@@ -12,24 +26,36 @@ import (
 	"unsafe"
 )
 
-type IOImpl interface {
+type IOReadImpl interface {
 	Open(g *HCL, name string, includer_name string) (int, error)
 	Close(fd int)
 	Read(fd int, buf []rune) (int, error)
+}
+
+type IOScanImpl interface {
+	Open(g *HCL) error
+	Close()
+	Read(buf []rune) (int, error)
+}
+
+type IOPrintImpl interface {
+	Open(g *HCL) error
+	Close()
 	Write(data []rune) error
 	WriteBytes(data []byte) error
 	Flush() error
 }
 
+type IOImplSet struct {
+	r IOReadImpl
+	s IOScanImpl
+	p IOPrintImpl
+}
+
 type HCL struct {
 	c       *C.hcl_t
 	inst_no int
-
+	io IOImplSet
-	io struct {
-		r IOImpl
-		s IOImpl
-		p IOImpl
-	}
 }
 
 type Ext struct {
@@ -92,12 +118,22 @@ func (hcl *HCL) AddBuiltinPrims() error {
 	return nil
 }
 
-func (hcl *HCL) AttachIO(r IOImpl, w IOImpl, p IOImpl) error {
+func (hcl *HCL) AttachIO(r IOReadImpl, s IOScanImpl, p IOPrintImpl) error {
+	var x C.int
+	var io IOImplSet
+
+	io = hcl.io
+
 	hcl.io.r = r
 	hcl.io.s = s
 	hcl.io.p = p
-	if C.hcl_attachio(hcl.c, go_read_handler, go_scan_handler, go_print_handler) <= -1 {
+
-		// TODO: restore to the old value..
+	x = C.hcl_attachio(hcl.c,
+		C.hcl_ioimpl_t(C.hcl_read_handler_for_go),
+		C.hcl_ioimpl_t(C.hcl_scan_handler_for_go),
+		C.hcl_ioimpl_t(C.hcl_print_handler_for_go))
+	if x <= -1 {
+		hcl.io = io // restore the set
 		return fmt.Errorf("unable to attach I/O handlers: %s", string(ucstr_to_rune_slice(C.hcl_geterrstr(hcl.c))))
 	}
 	return nil

main.go

@@ -126,14 +126,14 @@ func main() {
 		goto oops
 	}
 
-	err = x.AttachIO(rfh, sfh, pfh)
+	err = x.AttachIO(&rfh, &sfh, &pfh)
 	if err != nil {
 		fmt.Printf("Error - %s", err.Error())
 	}
-	x.FeedString(`(printf ">>>>>>>>> [%d]\n" (+ 30 455))
+	x.FeedString([]rune(`(printf ">>>>>>>>> [%d]\n" (+ 30 455))
 	   (printf ">>>>>>>>> [%d]\n" (+ 11 455))
 	   #include "a.hcl"
-	   (printf ">>>>>>>>> [%d]\n" (+ 20 455))`)
+	   (printf ">>>>>>>>> [%d]\n" (+ 20 455))`))
 
 	x.EndFeed()
 	x.Execute()