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remove test and try expressions in favor of if expressions

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See #357
This commit is contained in:
Andrew Kelley
2017-05-03 17:23:11 -04:00
parent 0940d46c01
commit 644ea2dde9
19 changed files with 148 additions and 226 deletions
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189
src/parser.cpp
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@@ -215,7 +215,7 @@ static AstNode *ast_parse_block_or_expression(ParseContext *pc, size_t *token_in
static AstNode *ast_parse_block_expr_or_expression(ParseContext *pc, size_t *token_index, bool mandatory);
static AstNode *ast_parse_expression(ParseContext *pc, size_t *token_index, bool mandatory);
static AstNode *ast_parse_block(ParseContext *pc, size_t *token_index, bool mandatory);
static AstNode *ast_parse_if_expr(ParseContext *pc, size_t *token_index, bool mandatory);
static AstNode *ast_parse_if_try_test_expr(ParseContext *pc, size_t *token_index, bool mandatory);
static AstNode *ast_parse_block_expr(ParseContext *pc, size_t *token_index, bool mandatory);
static AstNode *ast_parse_unwrap_expr(ParseContext *pc, size_t *token_index, bool mandatory);
static AstNode *ast_parse_prefix_op_expr(ParseContext *pc, size_t *token_index, bool mandatory);
@@ -639,110 +639,6 @@ static AstNode *ast_parse_comptime_expr(ParseContext *pc, size_t *token_index, b
return node;
}
/*
TryExpression(body) = "try" "(" Expression ")" option("|" option("*") Symbol "|") body option("else" option("|" Symbol "|") BlockExpression(body))
*/
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);
node->data.try_expr.target_node = ast_parse_expression(pc, token_index, true);
ast_eat_token(pc, token_index, TokenIdRParen);
Token *open_bar_tok = &pc->tokens->at(*token_index);
if (open_bar_tok->id == TokenIdBinOr) {
*token_index += 1;
Token *star_tok = &pc->tokens->at(*token_index);
if (star_tok->id == TokenIdStar) {
*token_index += 1;
node->data.try_expr.var_is_ptr = true;
}
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, TokenIdBinOr);
}
node->data.try_expr.then_node = ast_parse_block_or_expression(pc, token_index, true);
Token *else_token = &pc->tokens->at(*token_index);
if (else_token->id == TokenIdKeywordElse) {
*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_block_expr_or_expression(pc, token_index, true);
}
return node;
}
/*
TestExpression(body) = "test" "(" Expression ")" option("|" option("*") Symbol "|") body option("else" BlockExpression(body))
*/
static AstNode *ast_parse_test_expr(ParseContext *pc, size_t *token_index, bool mandatory) {
Token *test_token = &pc->tokens->at(*token_index);
if (test_token->id == TokenIdKeywordTest) {
*token_index += 1;
} else if (mandatory) {
ast_expect_token(pc, test_token, TokenIdKeywordTest);
zig_unreachable();
} else {
return nullptr;
}
AstNode *node = ast_create_node(pc, NodeTypeTestExpr, test_token);
ast_eat_token(pc, token_index, TokenIdLParen);
node->data.test_expr.target_node = ast_parse_expression(pc, token_index, true);
ast_eat_token(pc, token_index, TokenIdRParen);
Token *open_bar_tok = &pc->tokens->at(*token_index);
if (open_bar_tok->id == TokenIdBinOr) {
*token_index += 1;
Token *star_tok = &pc->tokens->at(*token_index);
if (star_tok->id == TokenIdStar) {
*token_index += 1;
node->data.test_expr.var_is_ptr = true;
}
Token *var_name_tok = ast_eat_token(pc, token_index, TokenIdSymbol);
node->data.test_expr.var_symbol = token_buf(var_name_tok);
ast_eat_token(pc, token_index, TokenIdBinOr);
}
node->data.test_expr.then_node = ast_parse_block_or_expression(pc, token_index, true);
Token *else_token = &pc->tokens->at(*token_index);
if (else_token->id == TokenIdKeywordElse) {
*token_index += 1;
node->data.test_expr.else_node = ast_parse_block_expr_or_expression(pc, token_index, true);
}
return node;
}
/*
PrimaryExpression = Number | String | CharLiteral | KeywordLiteral | GroupedExpression | GotoExpression | BlockExpression(BlockOrExpression) | Symbol | ("@" Symbol FnCallExpression) | ArrayType | (option("extern") FnProto) | AsmExpression | ("error" "." Symbol) | ContainerDecl
KeywordLiteral = "true" | "false" | "null" | "break" | "continue" | "undefined" | "error" | "this" | "unreachable"
@@ -1434,8 +1330,10 @@ static AstNode *ast_parse_bool_and_expr(ParseContext *pc, size_t *token_index, b
/*
IfExpression(body) = "if" "(" Expression ")" body option("else" BlockExpression(body))
TryExpression(body) = "if" "(" Expression ")" option("|" option("*") Symbol "|") body "else" "|" Symbol "|" BlockExpression(body)
TestExpression(body) = "if" "(" Expression ")" "|" option("*") Symbol "|" body option("else" BlockExpression(body))
*/
static AstNode *ast_parse_if_expr(ParseContext *pc, size_t *token_index, bool mandatory) {
static AstNode *ast_parse_if_try_test_expr(ParseContext *pc, size_t *token_index, bool mandatory) {
Token *if_token = &pc->tokens->at(*token_index);
if (if_token->id == TokenIdKeywordIf) {
@@ -1448,19 +1346,72 @@ static AstNode *ast_parse_if_expr(ParseContext *pc, size_t *token_index, bool ma
}
ast_eat_token(pc, token_index, TokenIdLParen);
AstNode *node = ast_create_node(pc, NodeTypeIfBoolExpr, if_token);
node->data.if_bool_expr.condition = ast_parse_expression(pc, token_index, true);
AstNode *condition = ast_parse_expression(pc, token_index, true);
ast_eat_token(pc, token_index, TokenIdRParen);
node->data.if_bool_expr.then_block = ast_parse_block_or_expression(pc, token_index, true);
Token *else_token = &pc->tokens->at(*token_index);
if (else_token->id == TokenIdKeywordElse) {
Token *open_bar_tok = &pc->tokens->at(*token_index);
Token *var_name_tok = nullptr;
bool var_is_ptr = false;
if (open_bar_tok->id == TokenIdBinOr) {
*token_index += 1;
node->data.if_bool_expr.else_node = ast_parse_block_expr_or_expression(pc, token_index, true);
Token *star_tok = &pc->tokens->at(*token_index);
if (star_tok->id == TokenIdStar) {
*token_index += 1;
var_is_ptr = true;
}
var_name_tok = ast_eat_token(pc, token_index, TokenIdSymbol);
ast_eat_token(pc, token_index, TokenIdBinOr);
}
return node;
AstNode *body_node = ast_parse_block_or_expression(pc, token_index, true);
Token *else_tok = &pc->tokens->at(*token_index);
AstNode *else_node = nullptr;
Token *err_name_tok = nullptr;
if (else_tok->id == TokenIdKeywordElse) {
*token_index += 1;
Token *else_bar_tok = &pc->tokens->at(*token_index);
if (else_bar_tok->id == TokenIdBinOr) {
*token_index += 1;
err_name_tok = ast_eat_token(pc, token_index, TokenIdSymbol);
ast_eat_token(pc, token_index, TokenIdBinOr);
}
else_node = ast_parse_block_expr_or_expression(pc, token_index, true);
}
if (err_name_tok != nullptr) {
AstNode *node = ast_create_node(pc, NodeTypeTryExpr, if_token);
node->data.try_expr.target_node = condition;
node->data.try_expr.var_is_ptr = var_is_ptr;
if (var_name_tok != nullptr) {
node->data.try_expr.var_symbol = token_buf(var_name_tok);
}
node->data.try_expr.then_node = body_node;
node->data.try_expr.err_symbol = token_buf(err_name_tok);
node->data.try_expr.else_node = else_node;
return node;
} else if (var_name_tok != nullptr) {
AstNode *node = ast_create_node(pc, NodeTypeTestExpr, if_token);
node->data.test_expr.target_node = condition;
node->data.test_expr.var_is_ptr = var_is_ptr;
node->data.test_expr.var_symbol = token_buf(var_name_tok);
node->data.test_expr.then_node = body_node;
node->data.test_expr.else_node = else_node;
return node;
} else {
AstNode *node = ast_create_node(pc, NodeTypeIfBoolExpr, if_token);
node->data.if_bool_expr.condition = condition;
node->data.if_bool_expr.then_block = body_node;
node->data.if_bool_expr.else_node = else_node;
return node;
}
}
/*
@@ -1848,7 +1799,7 @@ BlockExpression(body) = Block | IfExpression(body) | TryExpression(body) | TestE
static AstNode *ast_parse_block_expr(ParseContext *pc, size_t *token_index, bool mandatory) {
Token *token = &pc->tokens->at(*token_index);
AstNode *if_expr = ast_parse_if_expr(pc, token_index, false);
AstNode *if_expr = ast_parse_if_try_test_expr(pc, token_index, false);
if (if_expr)
return if_expr;
@@ -1872,14 +1823,6 @@ 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;
AstNode *test_node = ast_parse_test_expr(pc, token_index, false);
if (test_node)
return test_node;
if (mandatory)
ast_invalid_token_error(pc, token);