Merge pull request #2 from LB--/tmp-make_signed

Template Metaprogramming: make_signed

Author: LB--

tmp-make_signed/LICENSE

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+This is free and unencumbered software released into the public domain.
+
+Anyone is free to copy, modify, publish, use, compile, sell, or
+distribute this software, either in source code form or as a compiled
+binary, for any purpose, commercial or non-commercial, and by any
+means.
+
+In jurisdictions that recognize copyright laws, the author or authors
+of this software dedicate any and all copyright interest in the
+software to the public domain. We make this dedication for the benefit
+of the public at large and to the detriment of our heirs and
+successors. We intend this dedication to be an overt act of
+relinquishment in perpetuity of all present and future rights to this
+software under copyright law.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+For more information, please refer to <http://unlicense.org>

tmp-make_signed/README.md

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+This snippet depends on tmp-identity.
+
+Usage examples:
+* http://stackoverflow.com/a/16377818/1959975
+* http://ideone.com/uNCPt5
+
+See wiki for documentation.

tmp-make_signed/make_signed.hpp

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+#ifndef TemplateMetaprogramming_MakeSigned_HeaderPlusPlus
+#define TemplateMetaprogramming_MakeSigned_HeaderPlusPlus
+
+#include <type_traits>
+#include "identity.hpp" //see ../tmp-identity/
+
+template<typename T>
+using make_signed = typename std::conditional
+<
+	std::is_integral<T>::value,
+	std::make_signed<T>,
+	identity<T>
+>::type;
+
+#endif