ClickHouse/dbms/include/DB/Parsers/ASTFunction.h
2014-09-29 17:36:30 +04:00

119 lines
2.9 KiB
C++

#pragma once
#include <DB/Parsers/ASTWithAlias.h>
#include <DB/Parsers/ASTExpressionList.h>
#include <DB/Functions/IFunction.h>
#include <DB/AggregateFunctions/IAggregateFunction.h>
#include <DB/IO/WriteBufferFromString.h>
namespace DB
{
/** Применение функции или оператора
*/
class ASTFunction : public ASTWithAlias
{
public:
enum FunctionKind
{
UNKNOWN,
TABLE_FUNCTION,
FUNCTION,
AGGREGATE_FUNCTION,
LAMBDA_EXPRESSION,
ARRAY_JOIN,
};
/// имя функции
String name;
/// аргументы
ASTPtr arguments;
/// параметры - для параметрических агрегатных функций. Пример: quantile(0.9)(x) - то, что в первых скобках - параметры.
ASTPtr parameters;
FunctionKind kind;
ASTFunction() : kind(UNKNOWN) {}
ASTFunction(StringRange range_) : ASTWithAlias(range_), kind(UNKNOWN) {}
String getColumnName() const
{
String res;
WriteBufferFromString wb(res);
writeString(name, wb);
if (parameters)
{
writeChar('(', wb);
for (ASTs::const_iterator it = parameters->children.begin(); it != parameters->children.end(); ++it)
{
if (it != parameters->children.begin())
writeCString(", ", wb);
writeString((*it)->getColumnName(), wb);
}
writeChar(')', wb);
}
writeChar('(', wb);
for (ASTs::const_iterator it = arguments->children.begin(); it != arguments->children.end(); ++it)
{
if (it != arguments->children.begin())
writeCString(", ", wb);
writeString((*it)->getColumnName(), wb);
}
writeChar(')', wb);
return res;
}
/** Получить текст, который идентифицирует этот элемент. */
String getID() const { return "Function_" + name; }
ASTPtr clone() const
{
ASTFunction * res = new ASTFunction(*this);
res->children.clear();
if (arguments) { res->arguments = arguments->clone(); res->children.push_back(res->arguments); }
if (parameters) { res->parameters = parameters->clone(); res->children.push_back(res->parameters); }
return res;
}
};
template <typename... Args>
ASTPtr makeASTFunction(const String & name, Args &&... args)
{
const auto function = new ASTFunction{};
ASTPtr result{function};
function->name = name;
function->arguments = new ASTExpressionList{};
function->children.push_back(function->arguments);
function->arguments->children = { std::forward<Args>(args)... };
return result;
}
template <typename... Args>
ASTPtr makeASTFunction(const String & name, const StringRange & function_range,
const StringRange & arguments_range, Args &&... args)
{
const auto function = new ASTFunction{function_range};
ASTPtr result{function};
function->name = name;
function->arguments = new ASTExpressionList{arguments_range};
function->children.push_back(function->arguments);
function->arguments->children = { std::forward<Args>(args)... };
return result;
}
}