added

vendor/github.com/glycerine/zygomys/zygo/channels.go

@@ -0,0 +1,70 @@
+package zygo
+
+import (
+	"errors"
+	"fmt"
+)
+
+type SexpChannel struct {
+	Val chan Sexp
+	Typ *RegisteredType
+}
+
+func (ch *SexpChannel) SexpString(ps *PrintState) string {
+	return "[chan]"
+}
+
+func (ch *SexpChannel) Type() *RegisteredType {
+	return ch.Typ // TODO what should this be?
+}
+
+func MakeChanFunction(env *Zlisp, name string,
+	args []Sexp) (Sexp, error) {
+	if len(args) > 1 {
+		return SexpNull, WrongNargs
+	}
+
+	size := 0
+	if len(args) == 1 {
+		switch t := args[0].(type) {
+		case *SexpInt:
+			size = int(t.Val)
+		default:
+			return SexpNull, errors.New(
+				fmt.Sprintf("argument to %s must be int", name))
+		}
+	}
+
+	return &SexpChannel{Val: make(chan Sexp, size)}, nil
+}
+
+func ChanTxFunction(env *Zlisp, name string,
+	args []Sexp) (Sexp, error) {
+	if len(args) < 1 {
+		return SexpNull, WrongNargs
+	}
+	var channel chan Sexp
+	switch t := args[0].(type) {
+	case *SexpChannel:
+		channel = chan Sexp(t.Val)
+	default:
+		return SexpNull, errors.New(
+			fmt.Sprintf("argument 0 of %s must be channel", name))
+	}
+
+	if name == "send" {
+		if len(args) != 2 {
+			return SexpNull, WrongNargs
+		}
+		channel <- args[1]
+		return SexpNull, nil
+	}
+
+	return <-channel, nil
+}
+
+func (env *Zlisp) ImportChannels() {
+	env.AddFunction("makeChan", MakeChanFunction)
+	env.AddFunction("send", ChanTxFunction)
+	env.AddFunction("<!", ChanTxFunction)
+}