implement string handling!

builtins.go

@@ -58,7 +58,7 @@ func (b *Builtins) OpenComment(c *Context) func(string) error {
 	}
 }
 
-// CloseComment resumes parsing
+// CloseComment resumes parsing by consuming itself and resetting the immediate flag
 func (b *Builtins) CloseComment(c *Context) func(string) error {
 	return func(_ string) error {
 		c.Flags.SetFlag("Immediate", false)
@@ -66,6 +66,36 @@ func (b *Builtins) CloseComment(c *Context) func(string) error {
 	}
 }
 
+// OpenQuote consumes text until its closing pair to output
+func (b *Builtins) OpenQuote(out io.Writer, r *Stack, close byte) func(string) error {
+	if out == nil {
+		out = os.Stdout
+	}
+	return func(next string) error {
+		w := []byte{}
+		for i := 0; i < len(next); i = i + 1 {
+			switch next[i] {
+			case close:
+				fmt.Fprint(out, string(w))
+				j, _ := r.Pop()
+				r.Push(j + i - 1) // push the end-point onto the stack
+				return nil
+			default:
+				w = append(w, next[i])
+				continue
+			}
+		}
+		return nil
+	}
+}
+
+// CloseQuote consumes itself.
+func (b *Builtins) CloseQuote(c *Context) func(string) error {
+	return func(next string) error {
+		return nil
+	}
+}
+
 // Eq compares TOS and NOS and puts -1 on the stack if they're equal, 0 otherwise.
 func (b *Builtins) Eq(s *Stack) func(string) error {
 	return func(_ string) error {

main.go

@@ -50,6 +50,10 @@ func main() {
 	dict.AddWord(".", Word{Name: ".", Impl: b.Print(os.Stdout, &stack)})
 	dict.AddWord("EMIT", Word{Name: "EMIT", Impl: b.Emit(os.Stdout, &stack)})
 	dict.AddWord("CR", Word{Name: "CR", Source: []string{"10", "EMIT"}}) // emit a newline
+	// strings
+	dict.AddWord(`."`, Word{Name: `."`, Impl: b.OpenQuote(os.Stdout, &rstack, '"')})
+	dict.AddWord(`"`, Word{Name: `"`, Impl: b.CloseQuote(&c)})
+	dict.AddWord(`.(`, Word{Name: `.(`, Impl: b.OpenQuote(os.Stdout, &rstack, ')'), Immediate: true})
 	// logic
 	dict.AddWord("=", Word{Name: "=", Impl: b.Eq(&stack)})
 	dict.AddWord("0=", Word{Name: "0=", Source: []string{"0", "="}})