Revert "Refactor to remove nested instance variable struct in object/…

…class"

This reverts commit 92cbe74.

class.go

@@ -27,7 +27,7 @@ type class struct {
 	Object
 	super RClass
 	mt
-	iv ivTable
+	iv
 }
 
 type Class struct {
@@ -192,18 +192,18 @@ func (mrb *State) defineMethodRaw(class RClass, name Symbol, method Method) {
 
 func (c *class) ivPut(sym Symbol, val Value) {
 	if c.iv == nil {
-		c.iv = make(ivTable)
+		c.iv = make(iv)
 	}
 
-	c.iv[sym] = val
+	c.iv.Put(sym, val)
 }
 
 func (c *class) ivGet(sym Symbol) Value {
 	if c.iv == nil {
 		return nil
 	}
 
-	return c.iv[sym]
+	return c.iv.Get(sym)
 }
 
 func (c *class) mtPut(sym Symbol, method Method) {

object.go

@@ -19,7 +19,7 @@ var _ RObject = &Object{}
 type Object struct {
 	class RClass
 	flags uint32
-	iv    ivTable
+	iv
 }
 
 func (obj *Object) Class() RClass {
@@ -32,18 +32,18 @@ func (obj *Object) Flags() uint32 {
 
 func (obj *Object) ivPut(sym Symbol, val Value) {
 	if obj.iv == nil {
-		obj.iv = make(ivTable)
+		obj.iv = make(iv)
 	}
 
-	obj.iv[sym] = val
+	obj.iv.Put(sym, val)
 }
 
 func (obj *Object) ivGet(sym Symbol) Value {
 	if obj.iv == nil {
 		return nil
 	}
 
-	return obj.iv[sym]
+	return obj.iv.Get(sym)
 }
 
 func (mrb *State) includeModuleAt(class, insPos, module RClass, superSearch int) int {

variable.go

@@ -1,6 +1,15 @@
 package mruby
 
 type ivTable map[Symbol]Value
+type iv = ivTable
+
+func (iv ivTable) Get(sym Symbol) Value {
+	return iv[sym]
+}
+
+func (iv ivTable) Put(sym Symbol, val Value) {
+	iv[sym] = val
+}
 
 func (mrb *State) ObjectInstanceVariableSetForce(obj RObject, name Symbol, val Value) {
 	obj.ivPut(name, val)