refactor objects

internal/object/bool.go

@@ -32,10 +32,24 @@ func (b Boolean) Inspect() string {
 	return fmt.Sprintf("%t", b.Value)
 }
 
-func (b Boolean) Clone() Object {
+// Copy implements the Copyable interface
+func (b Boolean) Copy() Object {
 	return Boolean{Value: b.Value}
 }
 
+// Hash implements the Hasher interface
+func (b Boolean) Hash() HashKey {
+	var value uint64
+
+	if b.Value {
+		value = 1
+	} else {
+		value = 0
+	}
+
+	return HashKey{Type: b.Type(), Value: value}
+}
+
 func (b Boolean) String() string {
 	return b.Inspect()
 }