motiejus/zig
1
Fork 0
Code Releases Activity

add try expression

Browse Source 
See #83
This commit is contained in:
Andrew Kelley
2017-02-02 17:09:27 -05:00
parent 8b1c6d8b76
commit c0b37e8514
12 changed files with 344 additions and 103 deletions
Download Patch File Download Diff File Expand all files Collapse all files

76
src/parser.cpp
View File

@@ -623,6 +623,71 @@ static AstNode *ast_parse_comptime_expr(ParseContext *pc, size_t *token_index, b
return node;
}
/*
TryExpression = "try" "(" ("const" | "var") option("*") Symbol "=" Expression ")" Expression option("else" option("|" Symbol "|") Expression)
*/
static AstNode *ast_parse_try_expr(ParseContext *pc, size_t *token_index, bool mandatory) {
Token *try_token = &pc->tokens->at(*token_index);
if (try_token->id == TokenIdKeywordTry) {
*token_index += 1;
} else if (mandatory) {
ast_expect_token(pc, try_token, TokenIdKeywordTry);
zig_unreachable();
} else {
return nullptr;
}
AstNode *node = ast_create_node(pc, NodeTypeTryExpr, try_token);
ast_eat_token(pc, token_index, TokenIdLParen);
Token *var_token = &pc->tokens->at(*token_index);
if (var_token->id == TokenIdKeywordVar) {
node->data.try_expr.var_is_const = false;
*token_index += 1;
} else if (var_token->id == TokenIdKeywordConst) {
node->data.try_expr.var_is_const = true;
*token_index += 1;
} else {
ast_invalid_token_error(pc, var_token);
}
Token *star_token = &pc->tokens->at(*token_index);
if (star_token->id == TokenIdStar) {
node->data.try_expr.var_is_ptr = true;
*token_index += 1;
}
Token *var_name_tok = ast_eat_token(pc, token_index, TokenIdSymbol);
node->data.try_expr.var_symbol = token_buf(var_name_tok);
ast_eat_token(pc, token_index, TokenIdEq);
node->data.try_expr.target_node = ast_parse_expression(pc, token_index, true);
ast_eat_token(pc, token_index, TokenIdRParen);
node->data.try_expr.then_node = ast_parse_expression(pc, token_index, true);
Token *else_token = &pc->tokens->at(*token_index);
if (else_token->id != TokenIdKeywordElse)
return node;
*token_index += 1;
Token *open_bar_tok = &pc->tokens->at(*token_index);
if (open_bar_tok->id == TokenIdBinOr) {
*token_index += 1;
Token *err_name_tok = ast_eat_token(pc, token_index, TokenIdSymbol);
node->data.try_expr.err_symbol = token_buf(err_name_tok);
ast_eat_token(pc, token_index, TokenIdBinOr);
}
node->data.try_expr.else_node = ast_parse_expression(pc, token_index, true);
return node;
}
/*
PrimaryExpression = Number | String | CharLiteral | KeywordLiteral | GroupedExpression | GotoExpression | BlockExpression | Symbol | ("@" Symbol FnCallExpression) | ArrayType | (option("extern") FnProto) | AsmExpression | ("error" "." Symbol) | ContainerDecl
KeywordLiteral = "true" | "false" | "null" | "break" | "continue" | "undefined" | "error" | "type" | "this"
@@ -1775,7 +1840,7 @@ static AstNode *ast_parse_switch_expr(ParseContext *pc, size_t *token_index, boo
}
/*
BlockExpression = IfExpression | Block | WhileExpression | ForExpression | SwitchExpression | CompTimeExpression
BlockExpression = IfExpression | Block | WhileExpression | ForExpression | SwitchExpression | CompTimeExpression | TryExpression
*/
static AstNode *ast_parse_block_expr(ParseContext *pc, size_t *token_index, bool mandatory) {
Token *token = &pc->tokens->at(*token_index);
@@ -1804,6 +1869,10 @@ static AstNode *ast_parse_block_expr(ParseContext *pc, size_t *token_index, bool
if (comptime_node)
return comptime_node;
AstNode *try_node = ast_parse_try_expr(pc, token_index, false);
if (try_node)
return try_node;
if (mandatory)
ast_invalid_token_error(pc, token);
@@ -2555,6 +2624,11 @@ void ast_visit_node_children(AstNode *node, void (*visit)(AstNode **, void *cont
visit_field(&node->data.if_var_expr.then_block, visit, context);
visit_field(&node->data.if_var_expr.else_node, visit, context);
break;
case NodeTypeTryExpr:
visit_field(&node->data.try_expr.target_node, visit, context);
visit_field(&node->data.try_expr.then_node, visit, context);
visit_field(&node->data.try_expr.else_node, visit, context);
break;
case NodeTypeWhileExpr:
visit_field(&node->data.while_expr.condition, visit, context);
visit_field(&node->data.while_expr.body, visit, context);