Added SelectArg and MemFunSelectArg*

The MemFunSelectArg* functions can be used to select
a specific argument from a signal. For example this would
select the string argument as argument to the callback:

Signal<void, int, float, string> signal;
signal.connect(MemFunSelectArg2(obj, &Object::takesOneStringArg));
signal.emit(10, 3.14, "hello");

...

void Object::takesOneStringArg(const string& value) {
...
}

1 files changed, 74 insertions, 0 deletions

diff --git a/src/FbTk/SelectArg.hh b/src/FbTk/SelectArg.hh
new file mode 100644
index 0000000..83626ad
--- /dev/null
+++ b/src/FbTk/SelectArg.hh
@@ -0,0 +1,74 @@
+// SelectArg.hh for FbTk
+// Copyright (c) 2010 Fluxbox Team (fluxgen at fluxbox dot org)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// 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 OR COPYRIGHT HOLDERS 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.
+
+#ifndef FBTK_STLUTIL_SELECT_ARG_HH
+#define FBTK_STLUTIL_SELECT_ARG_HH
+
+#include "STLUtil.hh"
+
+namespace FbTk {
+
+namespace STLUtil {
+
+/**
+ * Selects a single argument from a maximum set of three arguments at compile time.
+ * For example:
+ * \begincode
+ * SelectArg<0>()( 10, 20, "hello" ); // returns first argument ( 10 )
+ * SelectArg<1>()( 10, "hello", 30 ); // returns second argument ( "hello" )
+ * SelectArg<2>()( 10, "hello", 30 ); // returns third argument ( 30 )
+ * \endcode
+ *
+ * The selection of argument 1 and 2 can return the last argument if the
+ * arguments are less or equal to two. For instance:
+ * \begincode
+ * SelectArg<1>()(10); // returns 10
+ * SelectArg<2>()(10, 20); // returns 20
+ * SelectArg<2>()(10); // returns 10
+ * \endcode
+ */
+template < int N >
+struct SelectArg {
+
+    template <typename Type1, typename Type2>
+    typename IfThenElse<N==0, Type1, Type2>::ResultType& operator ()(Type1& a, Type2& b){
+        return IfThenElse<N==0, Type1, Type2>()(a, b);
+    }
+
+    template <typename Type1, typename Type2, typename Type3>
+    typename IfThenElse<N==0, Type1,
+                        typename IfThenElse<N==1, Type2, Type3>::ResultType>::ResultType&
+     operator () (Type1& a, Type2& b, Type3& c) {
+        return IfThenElse<N==0, Type1,
+            typename IfThenElse<N==1, Type2, Type3>::ResultType>()
+            (a, IfThenElse<N==1, Type2, Type3>() (b, c) );
+    }
+
+    template < typename Type1 >
+    Type1 operator() (Type1 a) {
+        return a;
+    }
+};
+
+} // end namespace STLUtil
+} // end namespace FbTk
+
+#endif // FBTK_STLUTIL_SELECT_ARG_HH