Add anyToString method

class.go

@@ -78,6 +78,10 @@ func (mrb *State) DefineClassId(name Symbol, super RClass) (RClass, error) {
 	return mrb.defineClass(name, super, mrb.ObjectClass)
 }
 
+func (mrb *State) ObjectClassName(obj Value) string {
+	return mrb.ClassName(mrb.Class(obj))
+}
+
 func (mrb *State) ClassName(class RClass) string {
 	if class == nil {
 		return ""

features/object.feature

@@ -28,4 +28,4 @@ Feature: Object
       end
       Hello.new.inspect
       """
-    Then there should return string "Hello"
+    Then there should return string like "#<Hello:0x[0-9a-f]+>"

godogs_test.go

@@ -4,6 +4,7 @@ import (
 	"flag"
 	"fmt"
 	"os"
+	"regexp"
 	"testing"
 
 	"github.com/cucumber/godog"
@@ -99,6 +100,24 @@ func (feat *RubyFeature) thereShouldReturnString(expected string) error {
 	return nil
 }
 
+func (feat *RubyFeature) thereShouldReturnStringLike(expected string) error {
+	actual, ok := feat.ret.(string)
+	if !ok {
+		return fmt.Errorf("expected string, got %T (%+v)", feat.ret, feat.ret)
+	}
+
+	expr, err := regexp.Compile(expected)
+	if err != nil {
+		return err
+	}
+
+	if !expr.MatchString(actual) {
+		return fmt.Errorf("string not matched %s", cmp.Diff(actual, expected))
+	}
+
+	return nil
+}
+
 func (feat *RubyFeature) thereShouldReturnSymbol(expected string) error {
 	ret, ok := feat.ret.(mruby.Symbol)
 	if !ok {
@@ -213,6 +232,7 @@ func InitializeScenario(s *godog.ScenarioContext) {
 	s.Step(`^there should return false$`, feat.thereShouldReturnFalse)
 	s.Step(`^there should return nil$`, feat.thereShouldReturnNil)
 	s.Step(`^there should return string "([^"]*)"$`, feat.thereShouldReturnString)
+	s.Step(`^there should return string like "([^"]*)"$`, feat.thereShouldReturnStringLike)
 	s.Step(`^there should return symbol "([^"]*)"$`, feat.thereShouldReturnSymbol)
 	s.Step(`^there should return object$`, feat.thereShouldReturnObject)
 	s.Step(`^there should return class "([^"]*)"$`, feat.thereShouldReturnClass)

kernel.go

@@ -13,9 +13,6 @@ func (mrb *State) Inspect(obj Value) string {
 
 func objectInspect(mrb *State, self Value) Value {
 	switch v := self.(type) {
-	case *Object:
-		name := mrb.ObjectInstanceVariableGet(v.Class(), _classname(mrb))
-		return name
 	case RClass:
 		name := mrb.ObjectInstanceVariableGet(v, _classname(mrb))
 		return name
@@ -24,7 +21,7 @@ func objectInspect(mrb *State, self Value) Value {
 	case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64:
 		return fmt.Sprintf("%d", v)
 	default:
-		return nil
+		return anyToString(mrb, self)
 	}
 }
 

object.go

@@ -1,5 +1,7 @@
 package mruby
 
+import "fmt"
+
 type RBasic interface {
 	Class() RClass
 	Flags() uint32
@@ -44,6 +46,11 @@ func (obj *Object) ivGet(sym Symbol) Value {
 	return obj.iv.Get(sym)
 }
 
+func anyToString(mrb *State, obj Value) Value {
+	className := mrb.ObjectClassName(obj)
+	return fmt.Sprintf("#<%s:%p>", className, obj)
+}
+
 func initObject(mrb *State) (err error) {
 	mrb.FalseClass, err = mrb.DefineClassId(_FalseClass(mrb), mrb.ObjectClass)
 	if err != nil {

value.go

@@ -19,6 +19,15 @@ func Test(v Value) bool {
 	return Bool(v)
 }
 
+func ObjectP(v Value) bool {
+	switch v.(type) {
+	case *Object:
+		return true
+	default:
+		return false
+	}
+}
+
 func ClassP(v Value) bool {
 	switch v.(type) {
 	case *Class: