Simplistic enable_if SFINAE helper implementation

Makefile.am

@@ -10,6 +10,7 @@ UTIL_INCLUDE =  \
     annotations.hpp \
     backtrace.hpp   \
     debug.hpp   \
+    enable_if.hpp   \
     except.hpp  \
     float.hpp	\
     io.hpp	\

enable_if.hpp

@@ -0,0 +1,33 @@
+/*
+ * This file is part of libgim.
+ *
+ * Waif is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ * 
+ * Waif is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with libgim.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2010 Danny Robson <danny@blubinc.net>
+ */
+
+#ifndef __ENABLE_IF_HPP
+#define __ENABLE_IF_HPP
+
+template <bool B, typename T>
+struct enable_if {
+    typedef T type;
+};
+
+
+template <typename T>
+struct enable_if<false, T>  { };
+
+
+#endif // __ENABLE_IF_HPP