Added overloaded support for str * int

vm/vm.go

@@ -526,6 +526,18 @@ func (vm *VM) executeBinaryOperation(op code.Opcode) error {
 	rightType := right.Type()
 
 	switch {
+
+	// " " * 4
+	case left.Type() == object.STRING_OBJ && right.Type() == object.INTEGER_OBJ:
+		leftVal := left.(*object.String).Value
+		rightVal := right.(*object.Integer).Value
+		return vm.push(&object.String{Value: strings.Repeat(leftVal, int(rightVal))})
+	// 4 * " "
+	case left.Type() == object.INTEGER_OBJ && right.Type() == object.STRING_OBJ:
+		leftVal := left.(*object.Integer).Value
+		rightVal := right.(*object.String).Value
+		return vm.push(&object.String{Value: strings.Repeat(rightVal, int(leftVal))})
+
 	case leftType == object.BOOLEAN_OBJ && rightType == object.BOOLEAN_OBJ:
 		return vm.executeBinaryBooleanOperation(op, left, right)
 	case leftType == object.INTEGER_OBJ && rightType == object.INTEGER_OBJ:

vm/vm_test.go

@@ -326,6 +326,8 @@ func TestStringExpressions(t *testing.T) {
 		{`"monkey"`, "monkey"},
 		{`"mon" + "key"`, "monkey"},
 		{`"mon" + "key" + "banana"`, "monkeybanana"},
+		{`" " * 4`, "    "},
+		{`4 * " "`, "    "},
 	}
 
 	runVmTests(t, tests)