add 'fold' test case

[SVN r16599]

test/fold.cpp

@@ -0,0 +1,39 @@
+//-----------------------------------------------------------------------------
+// boost mpl/test/fold.cpp source file
+// See http://www.boost.org for updates, documentation, and revision history.
+//-----------------------------------------------------------------------------
+//
+// Copyright (c) 2000-02
+// Aleksey Gurtovoy
+//
+// Permission to use, copy, modify, distribute and sell this software
+// and its documentation for any purpose is hereby granted without fee, 
+// provided that the above copyright notice appears in all copies and 
+// that both the copyright notice and this permission notice appear in 
+// supporting documentation. No representations are made about the 
+// suitability of this software for any purpose. It is provided "as is" 
+// without express or implied warranty.
+
+#include "boost/mpl/fold.hpp"
+#include "boost/mpl/vector.hpp"
+#include "boost/mpl/next.hpp"
+#include "boost/mpl/if.hpp"
+#include "boost/mpl/integral_c.hpp"
+#include "boost/type_traits/is_float.hpp"
+#include "boost/static_assert.hpp"
+
+using namespace boost::mpl;
+
+int main()
+{
+    typedef vector<long,float,short,double,float,long,long double> types;
+    typedef fold<
+          types
+        , integral_c<long, 0>
+        , if_< boost::is_float<_2>,next<_1>,_1 >
+        >::type number_of_floats;
+
+    BOOST_STATIC_ASSERT(number_of_floats::value == 4);
+
+    return 0;
+}