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This commit is contained in:
Alexey Milovidov 2022-01-09 08:12:34 +03:00
parent b72818f6d6
commit fa0a9aa989
3 changed files with 6 additions and 11 deletions
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2
src/Parsers/CommonParsers.cpp
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@ -35,8 +35,6 @@ bool ParserKeyword::parseImpl(Pos & pos, [[maybe_unused]] ASTPtr & node, Expecte
current_word = next_whitespace + 1;
}
/// Avoid excessive backtracking.
pos.putBarrier();
return true;
}

11
src/Parsers/ExpressionElementParsers.cpp
View File

@ -688,6 +688,9 @@ bool ParserFunction::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
return false;
++pos;
/// Avoid excessive backtracking.
pos.putBarrier();
/// Special cases for expressions that look like functions but contain some syntax sugar:
/// CAST, EXTRACT, POSITION, EXISTS
@ -715,9 +718,7 @@ bool ParserFunction::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
String function_name = getIdentifierName(identifier);
String function_name_lowercase = Poco::toLower(function_name);
pos.no_backtrack_if_failure = true;
bool parsed_special_function = false;
std::optional<bool> parsed_special_function;
if (function_name_lowercase == "cast")
parsed_special_function = parseCastAs(pos, node, expected);
@ -745,8 +746,8 @@ bool ParserFunction::parseImpl(Pos & pos, ASTPtr & node, Expected & expected)
|| function_name_lowercase == "timestampdiff" || function_name_lowercase == "timestamp_diff")
parsed_special_function = parseDateDiff(pos, node, expected);
if (parsed_special_function)
return ParserToken(TokenType::ClosingRoundBracket).ignore(pos);
if (parsed_special_function.has_value())
return parsed_special_function.value() && ParserToken(TokenType::ClosingRoundBracket).ignore(pos);
auto pos_after_bracket = pos;
auto old_expected = expected;

4
src/Parsers/IParserBase.h
View File

@ -31,11 +31,7 @@ public:
bool res = func();
pos.decreaseDepth();
if (!res)
{
if (!(pos <= begin))
std::cerr << "Backtracked from " << pos->begin << " to " << begin->begin << "\n";
pos = begin;
}
return res;
}