ClickHouse/src/Parsers/IParserBase.h
2022-01-09 04:28:24 +03:00

45 lines
942 B
C++

#pragma once
#include <Parsers/IParser.h>
namespace DB
{
/** Base class for most parsers
*/
class IParserBase : public IParser
{
public:
template <typename F>
ALWAYS_INLINE static bool wrapParseImpl(Pos & pos, const F & func)
{
Pos begin = pos;
bool res = func();
if (!res && !pos.no_backtrack_on_failure)
pos = begin;
return res;
}
struct IncreaseDepthTag {};
template <typename F>
ALWAYS_INLINE static bool wrapParseImpl(Pos & pos, IncreaseDepthTag, const F & func)
{
Pos begin = pos;
pos.increaseDepth();
bool res = func();
pos.decreaseDepth();
if (!res && !pos.no_backtrack_on_failure)
pos = begin;
return res;
}
bool parse(Pos & pos, ASTPtr & node, Expected & expected) override; // -V1071
protected:
virtual bool parseImpl(Pos & pos, ASTPtr & node, Expected & expected) = 0;
};
}