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sqlpp11/include/sqlpp11/alias.h
rbock a38a9d6f65 Made a bunch of compile errors easier to read
Fixed a few bugs in the process, too.
Probably also created a few, need better checks for resulting
statements.
2014-03-23 20:54:44 +01:00

72 lines
2.4 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_ALIAS_H
#define SQLPP_ALIAS_H
#include <sqlpp11/type_traits.h>
namespace sqlpp
{
template<typename Expression, typename AliasProvider>
struct expression_alias_t
{
static_assert(is_expression_t<Expression>::value, "invalid argument for an expression alias");
static_assert(not is_alias_t<Expression>::value, "cannot create an alias of an alias");
struct _value_type: Expression::_value_type
{
using _is_expression = std::false_type;
using _is_named_expression = std::true_type;
using _is_alias = std::true_type;
};
using _name_t = typename AliasProvider::_name_t;
Expression _expression;
};
namespace vendor
{
template<typename Context, typename Expression, typename AliasProvider>
struct serializer_t<Context, expression_alias_t<Expression, AliasProvider>>
{
using T = expression_alias_t<Expression, AliasProvider>;
static Context& _(const T& t, Context& context)
{
context << '(';
serialize(t._expression, context);
context << ") AS ";
context << T::_name_t::_get_name();
return context;
}
};
}
}
#endif