added the debug variable for easy toggling of debug messages

interp/eval.go

@@ -5,12 +5,14 @@ import (
 	"unsafe"
 )
 
+var debug bool = false
+
 var err_num_args *error_t = &error_t{msg: "wrong number of arguments"}
 
 /*
-	   value stack (p.stack)
+	   value stack (p.vstack)
 
-		           <--- SP
+		           <--- SP (p.vsp)
 		    ARG1
 		    ARG0
 		    NAME
@@ -20,24 +22,26 @@ var err_num_args *error_t = &error_t{msg: "wrong number of arguments"}
 */
 
 func (p *process_t) push_cnode_value(val *Cnode_t) error {
-	if p.sp >= cap(p.stack) {
+	if p.vsp >= cap(p.vstack) {
 		return fmt.Errorf("stack full")
 	}
 
-	p.stack[p.sp] = unsafe.Pointer(uintptr(unsafe.Pointer(val)) | 1)
-	p.sp++
+	// TODO: using the last bit won't be compatible with go's GC.
+	// CHANGE to use inteface{} or devise a different scheme...
+	p.vstack[p.vsp] = unsafe.Pointer(uintptr(unsafe.Pointer(val)) | 1)
+	p.vsp++
 	p.ctx.count++
 
 	return nil
 }
 
 func (p *process_t) push_string_value(val string) error {
-	if p.sp >= cap(p.stack) {
+	if p.vsp >= cap(p.vstack) {
 		return fmt.Errorf("stack full")
 	}
 
-	p.stack[p.sp] = unsafe.Pointer(&val)
-	p.sp++
+	p.vstack[p.vsp] = unsafe.Pointer(&val)
+	p.vsp++
 	p.ctx.count++
 
 	return nil
@@ -46,22 +50,22 @@ func (p *process_t) push_string_value(val string) error {
 func (p *process_t) merge_top_values() error {
 	var new_val string
 
-	if p.sp < 2 {
+	if p.vsp < 2 {
 		return fmt.Errorf("stack corrupt")
 	}
-	new_val = *(*string)(p.stack[p.sp-2]) + *(*string)(p.stack[p.sp-1])
-	p.sp--
-	p.stack[p.sp] = nil
-	p.stack[p.sp-1] = unsafe.Pointer(&new_val)
+	new_val = *(*string)(p.vstack[p.vsp-2]) + *(*string)(p.vstack[p.vsp-1])
+	p.vsp--
+	p.vstack[p.vsp] = nil
+	p.vstack[p.vsp-1] = unsafe.Pointer(&new_val)
 	p.ctx.count--
 	return nil
 }
 
 func (p *process_t) pop_value() unsafe.Pointer {
 	var v unsafe.Pointer
-	p.sp--
-	v = p.stack[p.sp]
-	p.stack[p.sp] = nil
+	p.vsp--
+	v = p.vstack[p.vsp]
+	p.vstack[p.vsp] = nil
 	return v
 }
 
@@ -78,6 +82,12 @@ func (p *process_t) call() error {
 		proc = proc_if
 	case "puts":
 		proc = proc_puts
+	case "true":
+		proc = proc_true
+	case "false":
+		proc = proc_false
+	case "null":
+		proc = proc_null
 	default:
 		proc = proc_unknown
 	}
@@ -85,11 +95,11 @@ func (p *process_t) call() error {
 }
 
 func (p *process_t) GetCalleeName() *string {
-	return (*string)(p.stack[p.sp-p.ctx.count+1])
+	return (*string)(p.vstack[p.vsp-p.ctx.count+1])
 }
 
 func (p *process_t) GetArg(idx int) unsafe.Pointer {
-	return (p.stack[p.sp-p.ctx.count+2+idx])
+	return (p.vstack[p.vsp-p.ctx.count+2+idx])
 }
 
 func (p *process_t) GetNumArgs() int {
@@ -97,96 +107,203 @@ func (p *process_t) GetNumArgs() int {
 }
 
 func (p *process_t) Return(val string) {
-	p.stack[p.sp-p.ctx.count] = unsafe.Pointer(&val)
+	p.vstack[p.vsp-p.ctx.count] = unsafe.Pointer(&val)
 }
 
-func (p *process_t) push_context(node *Cnode_t) {
-	p.ctx = &context_t{count: 0, parent_ctx: p.ctx, parent_node: node}
+func (p *process_t) push_context(node *Cnode_t, container_node *Cnode_t) {
+	p.ctx = &context_t{count: 0, parent_ctx: p.ctx, parent_node: node, container_node: container_node}
 }
 
-func (p *process_t) pop_context() (node *Cnode_t) {
-	var i int
+func (p *process_t) pop_context(clear_vstack bool) (*Cnode_t, *Cnode_t) {
+	var (
+		i         int
+		node      *Cnode_t
+		container *Cnode_t
+	)
 
 	node = p.ctx.parent_node
+	container = p.ctx.container_node
 
-	// clean up the unused part of the stack
-	for i = 1; i < p.ctx.count; i++ {
-		p.stack[p.sp-p.ctx.count+i] = nil
+	if clear_vstack {
+		// clean up the unused part of the stack
+		for i = 1; i < p.ctx.count; i++ {
+			p.vstack[p.vsp-p.ctx.count+i] = nil
+		}
+
+		// pop off the cleaned arguments
+		p.vsp -= p.ctx.count - 1 // keep the return value in the stack
 	}
-
-	// pop off the cleaned arguments
-	p.sp -= p.ctx.count - 1 // keep the return value in the stack
 	p.ctx = p.ctx.parent_ctx
 
 	if p.ctx != nil {
 		p.ctx.count++ // let the return value be the argument to the caller
 	}
-	return
+
+	return node, container
+}
+
+func (interp *Interp) dump_vstack(p *process_t) {
+	//fmt.Printf("DDDDDDDDDDDDBVVVVVVVVVVVDDDd\n")
+	fmt.Printf("p.VSP => %d\n", p.vsp)
+	for i := 0; i < p.vsp; i++ {
+		x := uintptr(p.vstack[i])
+		if x&1 == 0 {
+			// string value
+			fmt.Printf(" %d => [%s]\n", i, *(*string)(p.vstack[i]))
+		} else {
+			// cnode value
+			fmt.Printf(" %d => cnode %p", i, p.vstack[i]) // TODO: strip 1 off
+		}
+	}
 }
 
 /*
-stmt
+	[STMT]
+		[TEXT] [DQUOTE] [TEXT]
 
-	   text text bracket
-		              stmt: text text
-					  stmt: text TEXT
+	[STMT]
+	    [BRACKET] [TEXT]
+		   [STMT]
+		      [TEXT] [TEXT] [TEXT]
+		   [STMT]
+		      [TEXT] [TEXT]
+
+"pu[null 1]ts" 10 20
+
+	[STMT]
+	     [DQUOTE] [TEXT|10] [TEXT|20]
+		    [TEXT|pu] [BRACKET] [JOIN] [TEXT|ts] [JOIN]
+			         [STMT]
+					    [TEXT|null] [TEXT|1]
 */
-func (interp *Interp) eval_atom_node(node *Cnode_t) (*string, error) {
+func (interp *Interp) eval_stmt_nodes(container_node *Cnode_t) (*string, error) {
 	var (
-		p     process_t
-		v     *string
-		inode *Cnode_t
-		err   error
+		p          process_t
+		v          *string
+		stmt_node  *Cnode_t
+		inner_node *Cnode_t
+		err        error
 	)
 
-	p.interp = interp
+	v = new(string) // TODO: change new(string) to a const
 
-	for node != nil {
-		p.push_context(node)
+	p.interp = interp
+	stmt_node = container_node.child // the first statement
+
+	//interp.dump_cnodes(container_node, true)
+	//fmt.Printf("--------------\n")
+	//interp.dump_cnodes(stmt_node, true)
+	//fmt.Printf("--------------\n")
+
+	fmt.Printf("START p.sp = %d\n", p.vsp)
+	for stmt_node != nil {
+		if stmt_node.code != CNODE_STMT {
+			panic("internal error - not statement node")
+		}
+
+		p.push_context(stmt_node, nil)
 		p.push_string_value("") // placeholder for return value
 
-		for inode = node.child; inode != nil; inode = inode.next {
-			switch inode.code {
+	start_over:
+		inner_node = stmt_node.child
+	resume:
+		for inner_node != nil {
+			//fmt.Printf("handling %d\n", inner_node.code)
+			switch inner_node.code {
 			case CNODE_BRACKET:
-				//p.push_context(inode)
-				//p.push_string_value("")
-				//node =
+				if inner_node.child != nil {
+					stmt_node = inner_node.child // first statement inside []
+					p.push_context(stmt_node, inner_node)
+					p.push_string_value("") // for return value
+					if debug {
+						fmt.Printf("going to start over\n")
+						interp.dump_cnodes(stmt_node, true)
+						fmt.Printf("\n--\n")
+					}
+					goto start_over
+				} else {
+					// no statements inside []. treat it like an empty string
+					p.push_string_value("")
+				}
+
+			case CNODE_DQUOTE:
+				if inner_node.child != nil {
+					p.push_context(stmt_node, inner_node)
+					//p.push_string_value("") // no placeholder for return value is needed
+					inner_node = inner_node.child
+					if debug {
+						fmt.Printf("going to start over\n")
+						interp.dump_cnodes(stmt_node, true)
+						fmt.Printf("\n--\n")
+					}
+					goto resume
+				} else {
+					// no statements inside []. treat it like an empty string
+					p.push_string_value("")
+				}
+
+			case CNODE_BRACE:
+				p.push_cnode_value(inner_node)
 
 			case CNODE_TEXT:
 
-				//fmt.Printf("XXXXXXXXXXXXXXXXXXXx[%s]\n", string(inode.token))
-				err = p.push_string_value(string(inode.token))
+				//fmt.Printf("XXXXXXXXXXXXXXXXXXXx[%s]\n", string(inner_node.token))
+				err = p.push_string_value(string(inner_node.token))
 				if err != nil {
 					goto oops
 				}
+
+				// TODO: many more types...
+			case CNODE_JOIN:
+				//fmt.Printf("JOIN>>>>>\n")
+				p.merge_top_values()
 			}
+
+			inner_node = inner_node.next
 		}
 
-		fmt.Printf("CALLING\n")
-		err = p.call()
-		if err != nil {
-			goto oops
+		if debug {
+			interp.dump_vstack(&p)
 		}
-		if p.ctx.parent_ctx != nil {
-			p.pop_context()
+		//fmt.Printf("p.ctx.parent_node.code %d p.ctx.container_node.code %d CNODE_STMT %d CNODE_DQUOTE %d\n", p.ctx.parent_node.code, p.ctx.container_node.code, CNODE_STMT, CNODE_DQUOTE)
+		//if p.ctx.parent_node.code == CNODE_STMT {
+		if p.ctx.container_node == nil || (p.ctx.container_node.code == CNODE_STMT || p.ctx.container_node.code == CNODE_BRACKET) {
+			if debug {
+				fmt.Printf("calling..... [%s]\n", *p.GetCalleeName())
+			}
+			err = p.call()
+			if err != nil {
+				goto oops
+			}
+
+			stmt_node, inner_node = p.pop_context(true)
+		} else {
+			stmt_node, inner_node = p.pop_context(false)
 		}
 
-		node = node.next
+		if inner_node != nil {
+			if debug {
+				fmt.Printf("resuming... %d\n", p.vsp)
+			}
+			inner_node = inner_node.next
+			goto resume
+		}
+
+		v = (*string)(p.pop_value()) // get the return value of the statement.
+		stmt_node = stmt_node.next
 	}
 
-	v = (*string)(p.pop_value())
-	p.pop_context()
-	if p.ctx != nil {
-		err = fmt.Errorf("internal error - dangling process context")
-		goto oops
+	if debug {
+		interp.dump_vstack(&p)
+		fmt.Printf("END p.sp = %d\n", p.vsp)
 	}
-
 	return v, nil
 
 oops:
 	return nil, err
 }
 
+/*
 func (interp *Interp) eval_atom_node_old(node *Cnode_t) (*string, error) {
 
 	var (
@@ -295,6 +412,7 @@ func (interp *Interp) eval_atom_node_old(node *Cnode_t) (*string, error) {
 oops:
 	return nil, err
 }
+*/
 
 func (interp *Interp) eval_arg(p *process_t, pos int) (*string, error) {
 	var (
@@ -304,8 +422,9 @@ func (interp *Interp) eval_arg(p *process_t, pos int) (*string, error) {
 	ptr = uintptr(p.GetArg(pos))
 	if ptr&1 == 1 { // cnode
 		ptr &= ^uintptr(1)
-		interp.dump_cnodes((*Cnode_t)(unsafe.Pointer(ptr)), true)
-		return interp.eval_atom_node((*Cnode_t)(unsafe.Pointer(ptr)).child)
+		//interp.dump_cnodes((*Cnode_t)(unsafe.Pointer(ptr)), true)
+		//return interp.eval_atom_node((*Cnode_t)(unsafe.Pointer(ptr)).child)
+		return interp.eval_stmt_nodes((*Cnode_t)(unsafe.Pointer(ptr)))
 	} else {
 		return (*string)(unsafe.Pointer(ptr)), nil
 	}

interp/pcl.go

@@ -34,15 +34,16 @@ const NULL_RUNE rune = '\u0000'
 const EOF_RUNE rune = rune(^0)
 
 type context_t struct {
-	count       int
-	parent_ctx  *context_t
-	parent_node *Cnode_t
+	count          int
+	parent_ctx     *context_t
+	parent_node    *Cnode_t
+	container_node *Cnode_t
 }
 
 type process_t struct {
 	interp *Interp
-	stack  [16]unsafe.Pointer // value stack - TODO: change size
-	sp     int
+	vstack [16]unsafe.Pointer // value stack - TODO: change size
+	vsp    int
 	ctx    *context_t
 }
 
@@ -245,7 +246,8 @@ func (interp *Interp) Execute(node_head *Cnode_t) (*string, error) {
 			break
 		}
 
-		v, err = interp.eval_atom_node(node.child)
+		//v, err = interp.eval_node_child(node.child)
+		v, err = interp.eval_stmt_nodes(node)
 		if err != nil {
 			return nil, err
 		}

interp/proc.go

@@ -70,6 +70,20 @@ func proc_puts(p *process_t) error {
 	return nil
 }
 
+func proc_false(p *process_t) error {
+	p.Return("false")
+	return nil
+}
+func proc_true(p *process_t) error {
+	p.Return("true")
+	return nil
+}
+
+func proc_null(p *process_t) error {
+	p.Return("")
+	return nil
+}
+
 func proc_unknown(p *process_t) error {
 	fmt.Printf("Unknown command - %s\n", *(p.GetCalleeName()))
 	return nil