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explicitly return from blocks

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instead of last statement being expression value

closes #629
This commit is contained in:
Andrew Kelley
2017-12-22 00:50:30 -05:00
parent 8bc523219c
commit d917815d81
114 changed files with 1203 additions and 1231 deletions
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53
src/parser.cpp
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@@ -748,7 +748,14 @@ static AstNode *ast_parse_primary_expr(ParseContext *pc, size_t *token_index, bo
node->data.fn_call_expr.is_builtin = true;
return node;
} else if (token->id == TokenIdSymbol) {
}
AstNode *block_expr_node = ast_parse_block_expr(pc, token_index, false);
if (block_expr_node) {
return block_expr_node;
}
if (token->id == TokenIdSymbol) {
*token_index += 1;
AstNode *node = ast_create_node(pc, NodeTypeSymbol, token);
node->data.symbol_expr.symbol = token_buf(token);
@@ -760,11 +767,6 @@ static AstNode *ast_parse_primary_expr(ParseContext *pc, size_t *token_index, bo
return grouped_expr_node;
}
AstNode *block_expr_node = ast_parse_block_expr(pc, token_index, false);
if (block_expr_node) {
return block_expr_node;
}
AstNode *array_type_node = ast_parse_array_type_expr(pc, token_index, false);
if (array_type_node) {
return array_type_node;
@@ -2145,9 +2147,6 @@ static AstNode *ast_parse_expression(ParseContext *pc, size_t *token_index, bool
return nullptr;
}
/*
Label: token(Symbol) token(Colon)
*/
static bool statement_terminates_without_semicolon(AstNode *node) {
switch (node->type) {
case NodeTypeIfBoolExpr:
@@ -2179,7 +2178,7 @@ static bool statement_terminates_without_semicolon(AstNode *node) {
}
/*
Block = option(Symbol ":") "{" many(Statement) option(Expression) "}"
Block = option(Symbol ":") "{" many(Statement) "}"
Statement = Label | VariableDeclaration ";" | Defer(Block) | Defer(Expression) ";" | BlockExpression(Block) | Expression ";" | ";" | ExportDecl
*/
static AstNode *ast_parse_block(ParseContext *pc, size_t *token_index, bool mandatory) {
@@ -2220,6 +2219,12 @@ static AstNode *ast_parse_block(ParseContext *pc, size_t *token_index, bool mand
}
for (;;) {
last_token = &pc->tokens->at(*token_index);
if (last_token->id == TokenIdRBrace) {
*token_index += 1;
return node;
}
AstNode *statement_node = ast_parse_local_var_decl(pc, token_index);
if (!statement_node)
statement_node = ast_parse_defer_expr(pc, token_index);
@@ -2228,32 +2233,14 @@ static AstNode *ast_parse_block(ParseContext *pc, size_t *token_index, bool mand
if (!statement_node)
statement_node = ast_parse_expression(pc, token_index, false);
bool semicolon_expected = true;
if (statement_node) {
node->data.block.statements.append(statement_node);
if (statement_terminates_without_semicolon(statement_node)) {
semicolon_expected = false;
} else {
if (statement_node->type == NodeTypeDefer) {
// defer without a block body requires a semicolon
Token *token = &pc->tokens->at(*token_index);
ast_expect_token(pc, token, TokenIdSemicolon);
}
}
if (!statement_node) {
ast_invalid_token_error(pc, last_token);
}
node->data.block.last_statement_is_result_expression = statement_node && statement_node->type != NodeTypeDefer;
node->data.block.statements.append(statement_node);
last_token = &pc->tokens->at(*token_index);
if (last_token->id == TokenIdRBrace) {
*token_index += 1;
return node;
} else if (!semicolon_expected) {
continue;
} else if (last_token->id == TokenIdSemicolon) {
*token_index += 1;
} else {
ast_invalid_token_error(pc, last_token);
if (!statement_terminates_without_semicolon(statement_node)) {
ast_eat_token(pc, token_index, TokenIdSemicolon);
}
}
zig_unreachable();