Allow for stmt to have empty clauses, resolved #58

source/toy_ast_node.c

@@ -135,6 +135,10 @@ static void freeASTNodeCustom(Toy_ASTNode* node, bool freeSelf) {
 			Toy_freeLiteral(node->import.identifier);
 			Toy_freeLiteral(node->import.alias);
 		break;
+
+		case TOY_AST_NODE_PASS:
+			//EMPTY
+		break;
 	}
 
 	if (freeSelf) {
@@ -383,3 +387,11 @@ void Toy_emitASTNodeImport(Toy_ASTNode** nodeHandle, Toy_Literal identifier, Toy
 
 	*nodeHandle = tmp;
 }
+
+void Toy_emitASTNodePass(Toy_ASTNode** nodeHandle) {
+	Toy_ASTNode* tmp = TOY_ALLOCATE(Toy_ASTNode, 1);
+
+	tmp->type = TOY_AST_NODE_PASS;
+
+	*nodeHandle = tmp;
+}

source/toy_ast_node.h

@@ -34,6 +34,7 @@ typedef enum Toy_ASTNodeType {
 	TOY_AST_NODE_PREFIX_DECREMENT, //decrement a variable
 	TOY_AST_NODE_POSTFIX_DECREMENT, //decrement a variable
 	TOY_AST_NODE_IMPORT, //import a library
+	TOY_AST_NODE_PASS, //for doing nothing
 } Toy_ASTNodeType;
 
 //literals
@@ -238,6 +239,9 @@ typedef struct Toy_NodeImport {
 	Toy_Literal alias;
 } Toy_NodeImport;
 
+//for doing nothing
+void Toy_emitASTNodePass(Toy_ASTNode** nodeHandle);
+
 union Toy_private_node {
 	Toy_ASTNodeType type;
 	Toy_NodeLiteral atomic;

source/toy_common.h

@@ -5,8 +5,8 @@
 #include <stdint.h>
 
 #define TOY_VERSION_MAJOR 0
-#define TOY_VERSION_MINOR 8
-#define TOY_VERSION_PATCH 3
+#define TOY_VERSION_MINOR 9
+#define TOY_VERSION_PATCH 0
 #define TOY_VERSION_BUILD __DATE__ " " __TIME__
 
 //platform/compiler-specific instructions

source/toy_compiler.c

@@ -965,6 +965,11 @@ static Toy_Opcode Toy_writeCompilerWithJumps(Toy_Compiler* compiler, Toy_ASTNode
 			return TOY_OP_INDEX_ASSIGN; //override binary's instruction IF it is assign
 		}
 		break;
+
+		case TOY_AST_NODE_PASS: {
+			return TOY_OP_PASS;
+		}
+		break;
 	}
 
 	return TOY_OP_EOF;

source/toy_interpreter.c

@@ -1827,6 +1827,10 @@ static void execInterpreter(Toy_Interpreter* interpreter) {
 
 	while(opcode != TOY_OP_EOF && opcode != TOY_OP_SECTION_END && !interpreter->panic) {
 		switch(opcode) {
+			case TOY_OP_PASS:
+				//DO NOTHING
+			break;
+
 			case TOY_OP_ASSERT:
 				if (!execAssert(interpreter)) {
 					return;

source/toy_opcodes.h

@@ -3,6 +3,9 @@
 typedef enum Toy_Opcode {
 	TOY_OP_EOF,
 
+	//do nothing
+	TOY_OP_PASS,
+
 	//basic statements
 	TOY_OP_ASSERT,
 	TOY_OP_PRINT,

source/toy_parser.c

@@ -1350,13 +1350,36 @@ static void forStmt(Toy_Parser* parser, Toy_ASTNode** nodeHandle) {
 	//read the clauses
 	consume(parser, TOY_TOKEN_PAREN_LEFT, "Expected '(' at beginning of for clause");
 
-	declaration(parser, &preClause); //allow defining variables in the pre-clause
+	//check the pre-clause
+	if (parser->current.type != TOY_TOKEN_SEMICOLON) {
+		declaration(parser, &preClause); //allow defining variables in the pre-clause
+	}
+	else {
+		consume(parser, TOY_TOKEN_SEMICOLON, "Expected ';' after empty declaration of for clause");
+		Toy_emitASTNodePass(&preClause);
+	}
 
-	parsePrecedence(parser, &condition, PREC_TERNARY);
-	consume(parser, TOY_TOKEN_SEMICOLON, "Expected ';' after condition of for clause");
+	//check the condition clause
+	if (parser->current.type != TOY_TOKEN_SEMICOLON) {
+		parsePrecedence(parser, &condition, PREC_TERNARY);
+		consume(parser, TOY_TOKEN_SEMICOLON, "Expected ';' after condition of for clause");
+	}
+	else {
+		consume(parser, TOY_TOKEN_SEMICOLON, "Expected ';' after empty condition of for clause");
+		//empty clause defaults to forever
+		Toy_Literal f = TOY_TO_BOOLEAN_LITERAL(true);
+		Toy_emitASTNodeLiteral(&condition, f);
+	}
 
-	parsePrecedence(parser, &postClause, PREC_ASSIGNMENT);
-	consume(parser, TOY_TOKEN_PAREN_RIGHT, "Expected ')' at end of for clause");
+	//check the postfix clause
+	if (parser->current.type != TOY_TOKEN_PAREN_RIGHT) {
+		parsePrecedence(parser, &postClause, PREC_ASSIGNMENT);
+		consume(parser, TOY_TOKEN_PAREN_RIGHT, "Expected ')' at end of for clause");
+	}
+	else {
+		consume(parser, TOY_TOKEN_PAREN_RIGHT, "Expected ')' after empty increment of for clause");
+		Toy_emitASTNodePass(&postClause);
+	}
 
 	//read the path
 	declaration(parser, &thenPath);