GDScript: Allow `is` operator to test built-in types

5 files changed, 75 insertions, 3 deletions

diff --git a/modules/gdscript/gdscript_compiler.cpp b/modules/gdscript/gdscript_compiler.cpp
index 1403184557..34c0cbd9ec 100644
--- a/modules/gdscript/gdscript_compiler.cpp
+++ b/modules/gdscript/gdscript_compiler.cpp
@@ -1253,6 +1253,25 @@ int GDScriptCompiler::_parse_expression(CodeGen &codegen, const GDScriptParser::
 					codegen.opcodes.push_back(src_address_b); // argument 2 (unary only takes one parameter)
 
 				} break;
+				case GDScriptParser::OperatorNode::OP_IS_BUILTIN: {
+					ERR_FAIL_COND_V(on->arguments.size() != 2, false);
+					ERR_FAIL_COND_V(on->arguments[1]->type != GDScriptParser::Node::TYPE_TYPE, false);
+
+					int slevel = p_stack_level;
+
+					int src_address_a = _parse_expression(codegen, on->arguments[0], slevel);
+					if (src_address_a < 0)
+						return -1;
+
+					if (src_address_a & GDScriptFunction::ADDR_TYPE_STACK << GDScriptFunction::ADDR_BITS)
+						slevel++; //uses stack for return, increase stack
+
+					const GDScriptParser::TypeNode *tn = static_cast<const GDScriptParser::TypeNode *>(on->arguments[1]);
+
+					codegen.opcodes.push_back(GDScriptFunction::OPCODE_IS_BUILTIN); // perform operator
+					codegen.opcodes.push_back(src_address_a); // argument 1
+					codegen.opcodes.push_back((int)tn->vtype); // argument 2 (unary only takes one parameter)
+				} break;
 				default: {
 
 					ERR_EXPLAIN("Bug in bytecode compiler, unexpected operator #" + itos(on->op) + " in parse tree while parsing expression.");
diff --git a/modules/gdscript/gdscript_function.cpp b/modules/gdscript/gdscript_function.cpp
index bae3f48923..d615b58b24 100644
--- a/modules/gdscript/gdscript_function.cpp
+++ b/modules/gdscript/gdscript_function.cpp
@@ -191,6 +191,7 @@ static String _get_var_type(const Variant *p_type) {
 	static const void *switch_table_ops[] = { \
 		&&OPCODE_OPERATOR,                    \
 		&&OPCODE_EXTENDS_TEST,                \
+		&&OPCODE_IS_BUILTIN,                  \
 		&&OPCODE_SET,                         \
 		&&OPCODE_GET,                         \
 		&&OPCODE_SET_NAMED,                   \
@@ -536,6 +537,21 @@ Variant GDScriptFunction::call(GDScriptInstance *p_instance, const Variant **p_a
 			}
 			DISPATCH_OPCODE;
 
+			OPCODE(OPCODE_IS_BUILTIN) {
+
+				CHECK_SPACE(4);
+
+				GET_VARIANT_PTR(value, 1);
+				Variant::Type var_type = (Variant::Type)_code_ptr[ip + 2];
+				GET_VARIANT_PTR(dst, 3);
+
+				GD_ERR_BREAK(var_type < 0 || var_type >= Variant::VARIANT_MAX);
+
+				*dst = value->get_type() == var_type;
+				ip += 4;
+			}
+			DISPATCH_OPCODE;
+
 			OPCODE(OPCODE_SET) {
 
 				CHECK_SPACE(3);
diff --git a/modules/gdscript/gdscript_function.h b/modules/gdscript/gdscript_function.h
index 3ce84290fd..633cca35d3 100644
--- a/modules/gdscript/gdscript_function.h
+++ b/modules/gdscript/gdscript_function.h
@@ -136,6 +136,7 @@ public:
 	enum Opcode {
 		OPCODE_OPERATOR,
 		OPCODE_EXTENDS_TEST,
+		OPCODE_IS_BUILTIN,
 		OPCODE_SET,
 		OPCODE_GET,
 		OPCODE_SET_NAMED,
diff --git a/modules/gdscript/gdscript_parser.cpp b/modules/gdscript/gdscript_parser.cpp
index a3f5e1819e..7f9598d47f 100644
--- a/modules/gdscript/gdscript_parser.cpp
+++ b/modules/gdscript/gdscript_parser.cpp
@@ -861,6 +861,20 @@ GDScriptParser::Node *GDScriptParser::_parse_expression(Node *p_parent, bool p_s
 			op->arguments.push_back(subexpr);
 			expr=op;*/
 
+		} else if (tokenizer->get_token() == GDScriptTokenizer::TK_PR_IS && tokenizer->get_token(1) == GDScriptTokenizer::TK_BUILT_IN_TYPE) {
+			// 'is' operator with built-in type
+			OperatorNode *op = alloc_node<OperatorNode>();
+			op->op = OperatorNode::OP_IS_BUILTIN;
+			op->arguments.push_back(expr);
+
+			tokenizer->advance();
+
+			TypeNode *tn = alloc_node<TypeNode>();
+			tn->vtype = tokenizer->get_token_type();
+			op->arguments.push_back(tn);
+			tokenizer->advance();
+
+			expr = op;
 		} else if (tokenizer->get_token() == GDScriptTokenizer::TK_BRACKET_OPEN) {
 			// array
 			tokenizer->advance();
@@ -1071,6 +1085,15 @@ GDScriptParser::Node *GDScriptParser::_parse_expression(Node *p_parent, bool p_s
 
 			expr = op;
 
+		} else if (tokenizer->get_token() == GDScriptTokenizer::TK_BUILT_IN_TYPE && expression.size() > 0 && expression[expression.size() - 1].is_op && expression[expression.size() - 1].op == OperatorNode::OP_IS) {
+			Expression e = expression[expression.size() - 1];
+			e.op = OperatorNode::OP_IS_BUILTIN;
+			expression.write[expression.size() - 1] = e;
+
+			TypeNode *tn = alloc_node<TypeNode>();
+			tn->vtype = tokenizer->get_token_type();
+			expr = tn;
+			tokenizer->advance();
 		} else {
 
 			//find list [ or find dictionary {
@@ -1329,6 +1352,7 @@ GDScriptParser::Node *GDScriptParser::_parse_expression(Node *p_parent, bool p_s
 			switch (expression[i].op) {
 
 				case OperatorNode::OP_IS:
+				case OperatorNode::OP_IS_BUILTIN:
 					priority = -1;
 					break; //before anything
 
@@ -5793,6 +5817,13 @@ GDScriptParser::DataType GDScriptParser::_reduce_node_type(Node *p_node) {
 		case Node::TYPE_CONSTANT: {
 			node_type = _type_from_variant(static_cast<ConstantNode *>(p_node)->value);
 		} break;
+		case Node::TYPE_TYPE: {
+			TypeNode *tn = static_cast<TypeNode *>(p_node);
+			node_type.has_type = true;
+			node_type.is_meta_type = true;
+			node_type.kind = DataType::BUILTIN;
+			node_type.builtin_type = tn->vtype;
+		} break;
 		case Node::TYPE_ARRAY: {
 			node_type.has_type = true;
 			node_type.kind = DataType::BUILTIN;
@@ -5896,7 +5927,8 @@ GDScriptParser::DataType GDScriptParser::_reduce_node_type(Node *p_node) {
 					// yield can return anything
 					node_type.has_type = false;
 				} break;
-				case OperatorNode::OP_IS: {
+				case OperatorNode::OP_IS:
+				case OperatorNode::OP_IS_BUILTIN: {
 
 					if (op->arguments.size() != 2) {
 						_set_error("Parser bug: binary operation without 2 arguments.", op->line);
@@ -5913,8 +5945,11 @@ GDScriptParser::DataType GDScriptParser::_reduce_node_type(Node *p_node) {
 						}
 						type_type.is_meta_type = false; // Test the actual type
 						if (!_is_type_compatible(type_type, value_type) && !_is_type_compatible(value_type, type_type)) {
-							// TODO: Make this a warning?
-							_set_error("A value of type '" + value_type.to_string() + "' will never be an instance of '" + type_type.to_string() + "'.", op->line);
+							if (op->op == OperatorNode::OP_IS) {
+								_set_error("A value of type '" + value_type.to_string() + "' will never be an instance of '" + type_type.to_string() + "'.", op->line);
+							} else {
+								_set_error("A value of type '" + value_type.to_string() + "' will never be of type '" + type_type.to_string() + "'.", op->line);
+							}
 							return DataType();
 						}
 					}
diff --git a/modules/gdscript/gdscript_parser.h b/modules/gdscript/gdscript_parser.h
index dbe523a0b9..3c51e3f372 100644
--- a/modules/gdscript/gdscript_parser.h
+++ b/modules/gdscript/gdscript_parser.h
@@ -345,6 +345,7 @@ public:
 			OP_PARENT_CALL,
 			OP_YIELD,
 			OP_IS,
+			OP_IS_BUILTIN,
 			//indexing operator
 			OP_INDEX,
 			OP_INDEX_NAMED,