ceph/src/boost/libs/parameter/test/optional_deduced_sfinae.cpp

   1 // Copyright Daniel Wallin 2006. Use, modification and distribution is
   2 // subject to the Boost Software License, Version 1.0. (See accompanying
   3 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   4
   5 #include <boost/parameter/preprocessor.hpp>
   6 #include <boost/parameter/name.hpp>
   7 #include <boost/type_traits/is_convertible.hpp>
   8 #include <boost/tuple/tuple.hpp>
   9 #include <string>
  10 #include "basics.hpp"
  11 #include <boost/utility/enable_if.hpp>
  12
  13 namespace test {
  14
  15 namespace mpl = boost::mpl;
  16
  17 using mpl::_;
  18 using boost::is_convertible;
  19
  20 BOOST_PARAMETER_NAME(x)
  21
  22 // Sun has problems with this syntax:
  23 //
  24 //   template1< r* ( template2<x> ) >
  25 //
  26 // Workaround: factor template2<x> into a separate typedef
  27
  28 #if BOOST_WORKAROUND(__SUNPRO_CC, BOOST_TESTED_AT(0x580))
  29
  30 typedef is_convertible<_,char const*> predicate;
  31
  32 BOOST_PARAMETER_FUNCTION((int), sfinae, tag,
  33   (deduced
  34      (optional (x, *(predicate), 0))
  35   )
  36 )
  37 {
  38     return 1;
  39 }
  40
  41 #else
  42
  43 BOOST_PARAMETER_FUNCTION((int), sfinae, tag,
  44   (deduced
  45      (optional (x, *(is_convertible<_,char const*>), 0))
  46   )
  47 )
  48 {
  49     return 1;
  50 }
  51
  52 #endif
  53
  54 template<class A0>
  55 typename boost::enable_if<boost::is_same<int,A0>, int>::type
  56 sfinae(A0 const& a0)
  57 {
  58     return 0;
  59 }
  60
  61 } // namespace test
  62
  63 int main()
  64 {
  65     using namespace test;
  66
  67     assert(sfinae() == 1);
  68     assert(sfinae("foo") == 1);
  69     assert(sfinae(1) == 0);
  70
  71     return 0;
  72 }
  73