Fix VM memory allocation optimizations by reducing what we allocate on the heap

internal/compiler/bytecode.go

@@ -70,13 +70,13 @@ func (e *encoder) WriteObjects(objs ...object.Object) (err error) {
 		err = errors.Join(err, e.WriteValue(obj.Type()))
 
 		switch o := obj.(type) {
-		case *object.Null:
+		case object.Null:
 			break
-		case *object.Boolean:
+		case object.Boolean:
 			err = errors.Join(err, e.WriteValue(o.Value))
-		case *object.Integer:
+		case object.Integer:
 			err = errors.Join(err, e.WriteValue(o.Value))
-		case *object.String:
+		case object.String:
 			err = errors.Join(err, e.WriteValue(len(o.Value)))
 			err = errors.Join(err, e.WriteValue(o.Value))
 		case *object.CompiledFunction:
@@ -146,13 +146,13 @@ func (d *decoder) Objects(len int) (o []object.Object) {
 	for i := 0; i < len; i++ {
 		switch t := object.Type(d.Int()); t {
 		case object.NullType:
-			o = append(o, &object.Null{})
+			o = append(o, object.Null{})
 		case object.BooleanType:
-			o = append(o, &object.Boolean{Value: d.Byte() == 1})
+			o = append(o, object.Boolean{Value: d.Byte() == 1})
 		case object.IntegerType:
-			o = append(o, &object.Integer{Value: d.Int64()})
+			o = append(o, object.Integer{Value: d.Int64()})
 		case object.StringType:
-			o = append(o, &object.String{Value: d.String(d.Int())})
+			o = append(o, object.String{Value: d.String(d.Int())})
 		case object.CFunctionType:
 			// The order of the fields has to reflect the data layout in the encoded bytecode.
 			o = append(o, &object.CompiledFunction{

internal/compiler/compiler.go

@@ -173,7 +173,7 @@ func (c *Compiler) Compile(node ast.Node) error {
 		}
 
 	case *ast.IntegerLiteral:
-		integer := &object.Integer{Value: node.Value}
+		integer := object.Integer{Value: node.Value}
 		c.emit(code.OpConstant, c.addConstant(integer))
 
 	case *ast.Null:
@@ -356,7 +356,7 @@ func (c *Compiler) Compile(node ast.Node) error {
 		c.loadSymbol(symbol)
 
 	case *ast.StringLiteral:
-		str := &object.String{Value: node.Value}
+		str := object.String{Value: node.Value}
 		c.emit(code.OpConstant, c.addConstant(str))
 
 	case *ast.ArrayLiteral:

internal/compiler/compiler_test.go

@@ -1220,16 +1220,16 @@ func testConstants2(t *testing.T, expected []interface{}, actual []object.Object
 			)
 
 		case string:
-			assert.Equal(constant, actual[i].(*object.String).Value)
+			assert.Equal(constant, actual[i].(object.String).Value)
 
 		case int:
-			assert.Equal(int64(constant), actual[i].(*object.Integer).Value)
+			assert.Equal(int64(constant), actual[i].(object.Integer).Value)
 		}
 	}
 }
 
 func testIntegerObject(expected int64, actual object.Object) interface{} {
-	result, ok := actual.(*object.Integer)
+	result, ok := actual.(object.Integer)
 	if !ok {
 		return fmt.Errorf("object is not Integer. got=%T (%+v", actual, actual)
 	}
@@ -1242,7 +1242,7 @@ func testIntegerObject(expected int64, actual object.Object) interface{} {
 }
 
 func testStringObject(expected string, actual object.Object) error {
-	result, ok := actual.(*object.String)
+	result, ok := actual.(object.String)
 	if !ok {
 		return fmt.Errorf("object is not String. got %T (%+v", actual, actual)
 	}