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sqlpp11/include/sqlpp11/vendor/is_null.h
2014-02-02 14:58:08 +01:00

88 lines
2.7 KiB
C++

/*
* Copyright (c) 2013, Roland Bock
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice, this
* list of conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef SQLPP_IS_NULL_H
#define SQLPP_IS_NULL_H
#include <sqlpp11/boolean.h>
#include <sqlpp11/type_traits.h>
#include <sqlpp11/detail/type_set.h>
namespace sqlpp
{
namespace vendor
{
template<bool NotInverted, typename Operand>
struct is_null_t: public boolean::template operators<is_null_t<NotInverted, Operand>>
{
static constexpr bool _inverted = not NotInverted;
struct _value_type: public boolean
{
using _is_named_expression = std::true_type;
};
struct _name_t
{
static constexpr const char* _get_name() { return _inverted ? "IS NOT NULL" : "IS NULL"; }
template<typename T>
struct _member_t
{
T in;
};
};
is_null_t(Operand operand):
_operand(operand)
{}
is_null_t(const is_null_t&) = default;
is_null_t(is_null_t&&) = default;
is_null_t& operator=(const is_null_t&) = default;
is_null_t& operator=(is_null_t&&) = default;
~is_null_t() = default;
Operand _operand;
};
template<typename Context, bool NotInverted, typename Operand>
struct interpreter_t<Context, ::sqlpp::vendor::is_null_t<NotInverted, Operand>>
{
using T = ::sqlpp::vendor::is_null_t<NotInverted, Operand>;
static Context& _(const T& t, Context& context)
{
interpret(t._operand, context);
context << (t._inverted ? " IS NOT NULL" : " IS NULL");
return context;
}
};
}
}
#endif