ClickHouse/dbms/include/DB/Interpreters/evaluateConstantExpression.h

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#pragma once
#include <memory>
#include <DB/Core/Field.h>
namespace DB
{
class IAST;
class Context;
class IDataType;
2017-02-17 20:27:32 +00:00
/** Evaluate constant expression and its type.
* Used in rare cases - for elements of set for IN, for data to INSERT.
* Quite suboptimal.
*/
std::pair<Field, std::shared_ptr<IDataType>> evaluateConstantExpression(std::shared_ptr<IAST> & node, const Context & context);
/** Evaluate constant expression
* and returns ASTLiteral with its value.
*/
std::shared_ptr<IAST> evaluateConstantExpressionAsLiteral(std::shared_ptr<IAST> & node, const Context & context);
/** Evaluate constant expression
* and returns ASTLiteral with its value.
* Also, if AST is identifier, then return string literal with its name.
* Useful in places where some name may be specified as identifier, or as result of a constant expression.
*/
std::shared_ptr<IAST> evaluateConstantExpressionOrIdentidierAsLiteral(std::shared_ptr<IAST> & node, const Context & context);
}