Add irb with minimal support

cmd/irb/main.go

@@ -0,0 +1,51 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+
+	"github.com/elct9620/mruby-go"
+)
+
+const (
+	exitCommand  = "exit"
+	inputPrompt  = "> "
+	outputPrompt = "=>"
+)
+
+func main() {
+	mrb, err := mruby.New()
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Print("mirb - Embeded Interactive Ruby Shell (Go Edition)\n\n")
+	fmt.Print(inputPrompt)
+
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if line == exitCommand {
+			break
+		}
+
+		ret, err := mrb.LoadString(line)
+
+		// NOTE: ret may be error
+		errRet, ok := ret.(error)
+		if ok {
+			err = errRet
+		}
+
+		if err != nil {
+			fmt.Println(err)
+		} else {
+			if ret != nil {
+				fmt.Printf("  %s %s\n", outputPrompt, mrb.Inspect(ret))
+			}
+		}
+
+		fmt.Print(inputPrompt)
+	}
+}

kernel.go

@@ -2,6 +2,15 @@ package mruby
 
 import "fmt"
 
+func (mrb *State) Inspect(obj Value) string {
+	ret, ok := objectInspect(mrb, obj).(string)
+	if !ok {
+		return ""
+	}
+
+	return ret
+}
+
 func objectInspect(mrb *State, self Value) Value {
 	switch v := self.(type) {
 	case *Object:
@@ -10,6 +19,10 @@ func objectInspect(mrb *State, self Value) Value {
 	case RClass:
 		name := mrb.ObjectInstanceVariableGet(v, _classname(mrb))
 		return name
+	case string:
+		return fmt.Sprintf("%q", v)
+	case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64:
+		return fmt.Sprintf("%d", v)
 	default:
 		return nil
 	}