ClickHouse/src/Parsers/ASTLiteral.h

50 lines
1.4 KiB
C++

#pragma once
#include <Core/Field.h>
#include <Parsers/ASTWithAlias.h>
#include <Parsers/TokenIterator.h>
#include <Common/FieldVisitors.h>
#include <optional>
namespace DB
{
/// Literal (atomic) - number, string, NULL
class ASTLiteral : public ASTWithAlias
{
public:
explicit ASTLiteral(Field && value_) : value(value_) {}
explicit ASTLiteral(const Field & value_) : value(value_) {}
Field value;
/// For ConstantExpressionTemplate
std::optional<TokenIterator> begin;
std::optional<TokenIterator> end;
/*
* The name of the column corresponding to this literal. Only used to
* disambiguate the literal columns with the same display name that are
* created at the expression analyzer stage. In the future, we might want to
* have a full separation between display names and column identifiers. For
* now, this field is effectively just some private EA data.
*/
String unique_column_name;
/** Get the text that identifies this element. */
String getID(char delim) const override { return "Literal" + (delim + applyVisitor(FieldVisitorDump(), value)); }
ASTPtr clone() const override { return std::make_shared<ASTLiteral>(*this); }
void updateTreeHashImpl(SipHash & hash_state) const override;
protected:
void formatImplWithoutAlias(const FormatSettings & settings, FormatState &, FormatStateStacked) const override;
void appendColumnNameImpl(WriteBuffer & ostr) const override;
};
}