wxWidgets/include/wx/meta/if.h
Vadim Zeitlin 3f66f6a5b3 Remove all lines containing cvs/svn "$Id$" keyword.
This keyword is not expanded by Git which means it's not replaced with the
correct revision value in the releases made using git-based scripts and it's
confusing to have lines with unexpanded "$Id$" in the released files. As
expanding them with Git is not that simple (it could be done with git archive
and export-subst attribute) and there are not many benefits in having them in
the first place, just remove all these lines.

If nothing else, this will make an eventual transition to Git simpler.

Closes #14487.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74602 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
2013-07-26 16:02:46 +00:00

73 lines
2.0 KiB
C++

/////////////////////////////////////////////////////////////////////////////
// Name: wx/meta/if.h
// Purpose: declares wxIf<> metaprogramming construct
// Author: Vaclav Slavik
// Created: 2008-01-22
// Copyright: (c) 2008 Vaclav Slavik
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#ifndef _WX_META_IF_H_
#define _WX_META_IF_H_
#include "wx/defs.h"
// NB: This code is intentionally written without partial templates
// specialization, because some older compilers (notably VC6) don't
// support it.
namespace wxPrivate
{
template <bool Cond>
struct wxIfImpl
// broken VC6 needs not just an incomplete template class declaration but a
// "skeleton" declaration of the specialized versions below as it apparently
// tries to look up the types in the generic template definition at some moment
// even though it ends up by using the correct specialization in the end -- but
// without this skeleton it doesn't recognize Result as a class at all below
#if defined(__VISUALC__) && !wxCHECK_VISUALC_VERSION(7)
{
template<typename TTrue, typename TFalse> struct Result {};
}
#endif // VC++ <= 6
;
// specialization for true:
template <>
struct wxIfImpl<true>
{
template<typename TTrue, typename TFalse> struct Result
{
typedef TTrue value;
};
};
// specialization for false:
template<>
struct wxIfImpl<false>
{
template<typename TTrue, typename TFalse> struct Result
{
typedef TFalse value;
};
};
} // namespace wxPrivate
// wxIf<> template defines nested type "value" which is the same as
// TTrue if the condition Cond (boolean compile-time constant) was met and
// TFalse if it wasn't.
//
// See wxVector<T> in vector.h for usage example
template<bool Cond, typename TTrue, typename TFalse>
struct wxIf
{
typedef typename wxPrivate::wxIfImpl<Cond>
::template Result<TTrue, TFalse>::value
value;
};
#endif // _WX_META_IF_H_