clone

object/object.go

@@ -29,6 +29,7 @@ const (
 // Mutable is the interface for all mutable objects which must implement
 // the Set() method which rebinds its internal value for assignment statements
 type Mutable interface {
+	Clone() Object
 	Set(obj Object)
 }
 
@@ -56,6 +57,9 @@ func (i *Integer) Inspect() string {
 func (i *Integer) Set(obj Object) {
 	i.Value = obj.(*Integer).Value
 }
+func (i *Integer) Clone() Object {
+	return &Integer{Value: i.Value}
+}
 
 type Boolean struct {
 	Value bool
@@ -67,8 +71,11 @@ func (b *Boolean) Type() ObjectType {
 func (b *Boolean) Inspect() string {
 	return fmt.Sprintf("%t", b.Value)
 }
-func (i *Boolean) Set(obj Object) {
-	i.Value = obj.(*Boolean).Value
+func (b *Boolean) Set(obj Object) {
+	b.Value = obj.(*Boolean).Value
+}
+func (b *Boolean) Clone() Object {
+	return &Boolean{Value: b.Value}
 }
 
 type Null struct{}
@@ -105,6 +112,9 @@ func (e *Error) Inspect() string {
 func (e *Error) Set(obj Object) {
 	e.Message = obj.(*Error).Message
 }
+func (e *Error) Clone() Object {
+	return &Error{Message: e.Message}
+}
 
 type Function struct {
 	Parameters []*ast.Identifier
@@ -147,6 +157,9 @@ func (s *String) Inspect() string {
 func (s *String) Set(obj Object) {
 	s.Value = obj.(*String).Value
 }
+func (s *String) Clone() Object {
+	return &String{Value: s.Value}
+}
 
 type BuiltinFunction func(args ...Object) Object
 
@@ -185,6 +198,11 @@ func (ao *Array) Inspect() string {
 func (ao *Array) Set(obj Object) {
 	ao.Elements = obj.(*Array).Elements
 }
+func (ao *Array) Clone() Object {
+	elements := make([]Object, len(ao.Elements))
+	copy(elements, ao.Elements)
+	return &Array{Elements: elements}
+}
 
 type HashKey struct {
 	Type  ObjectType
@@ -247,6 +265,13 @@ func (h *Hash) Inspect() string {
 func (h *Hash) Set(obj Object) {
 	h.Pairs = obj.(*Hash).Pairs
 }
+func (h *Hash) Clone() Object {
+	pairs := make(map[HashKey]HashPair)
+	for k, v := range h.Pairs {
+		pairs[k] = v
+	}
+	return &Hash{Pairs: pairs}
+}
 
 func (cf *CompiledFunction) Type() ObjectType {
 	return COMPILED_FUNCTION_OBJ