motiejus/zig
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allow empty function and return with no expression

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This commit is contained in:
Andrew Kelley
2015-11-27 10:52:31 -07:00
parent 821907317e
commit 9ca9a2c554
4 changed files with 107 additions and 23 deletions
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30
src/parser.cpp
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@@ -128,7 +128,8 @@ void ast_print(AstNode *node, int indent) {
break;
case NodeTypeStatementReturn:
fprintf(stderr, "ReturnStatement\n");
ast_print(node->data.statement_return.expression, indent + 2);
if (node->data.statement_return.expression)
ast_print(node->data.statement_return.expression, indent + 2);
break;
case NodeTypeExternBlock:
{
@@ -258,7 +259,7 @@ void ast_invalid_token_error(ParseContext *pc, Token *token) {
ast_error(token, "invalid token: '%s'", buf_ptr(&token_value));
}
static AstNode *ast_parse_expression(ParseContext *pc, int token_index, int *new_token_index);
static AstNode *ast_parse_expression(ParseContext *pc, int *token_index, bool mandatory);
static void ast_expect_token(ParseContext *pc, Token *token, TokenId token_id) {
@@ -374,7 +375,7 @@ static void ast_parse_fn_call_param_list(ParseContext *pc, int token_index, int
}
for (;;) {
AstNode *expr = ast_parse_expression(pc, token_index, &token_index);
AstNode *expr = ast_parse_expression(pc, &token_index, true);
params->append(expr);
Token *token = &pc->tokens->at(token_index);
@@ -411,28 +412,29 @@ static AstNode *ast_parse_fn_call(ParseContext *pc, int token_index, int *new_to
/*
Expression : token(Number) | token(String) | token(Unreachable) | FnCall
*/
static AstNode *ast_parse_expression(ParseContext *pc, int token_index, int *new_token_index) {
Token *token = &pc->tokens->at(token_index);
static AstNode *ast_parse_expression(ParseContext *pc, int *token_index, bool mandatory) {
Token *token = &pc->tokens->at(*token_index);
AstNode *node = ast_create_node(NodeTypeExpression, token);
if (token->id == TokenIdKeywordUnreachable) {
node->data.expression.type = AstNodeExpressionTypeUnreachable;
token_index += 1;
*token_index += 1;
} else if (token->id == TokenIdSymbol) {
node->data.expression.type = AstNodeExpressionTypeFnCall;
node->data.expression.data.fn_call = ast_parse_fn_call(pc, token_index, &token_index);
node->data.expression.data.fn_call = ast_parse_fn_call(pc, *token_index, token_index);
} else if (token->id == TokenIdNumberLiteral) {
node->data.expression.type = AstNodeExpressionTypeNumber;
ast_buf_from_token(pc, token, &node->data.expression.data.number);
token_index += 1;
*token_index += 1;
} else if (token->id == TokenIdStringLiteral) {
node->data.expression.type = AstNodeExpressionTypeString;
parse_string_literal(pc, token, &node->data.expression.data.string);
token_index += 1;
} else {
*token_index += 1;
} else if (mandatory) {
ast_invalid_token_error(pc, token);
} else {
return nullptr;
}
*new_token_index = token_index;
return node;
}
@@ -441,14 +443,14 @@ Statement : ExpressionStatement | ReturnStatement ;
ExpressionStatement : Expression token(Semicolon) ;
ReturnStatement : token(Return) Expression token(Semicolon) ;
ReturnStatement : token(Return) option(Expression) token(Semicolon) ;
*/
static AstNode *ast_parse_statement(ParseContext *pc, int token_index, int *new_token_index) {
Token *token = &pc->tokens->at(token_index);
if (token->id == TokenIdKeywordReturn) {
AstNode *node = ast_create_node(NodeTypeStatementReturn, token);
token_index += 1;
node->data.statement_return.expression = ast_parse_expression(pc, token_index, &token_index);
node->data.statement_return.expression = ast_parse_expression(pc, &token_index, false);
Token *semicolon = &pc->tokens->at(token_index);
token_index += 1;
@@ -460,7 +462,7 @@ static AstNode *ast_parse_statement(ParseContext *pc, int token_index, int *new_
token->id == TokenIdKeywordUnreachable ||
token->id == TokenIdNumberLiteral)
{
AstNode *node = ast_parse_expression(pc, token_index, &token_index);
AstNode *node = ast_parse_expression(pc, &token_index, true);
Token *semicolon = &pc->tokens->at(token_index);
token_index += 1;