1 // Copyright Daniel Wallin, David Abrahams 2005. Use, modification and
2 // distribution is subject to the Boost Software License, Version 1.0. (See
3 // accompanying file LICENSE_1_0.txt or copy at
4 // http://www.boost.org/LICENSE_1_0.txt)
6 #ifndef DEFAULT_050329_HPP
7 #define DEFAULT_050329_HPP
9 namespace boost { namespace parameter { namespace aux {
11 // A wrapper for the default value passed by the user when resolving
12 // the value of the parameter with the given Keyword
13 template <class Keyword, class Value>
26 // A wrapper for the default value computation function passed by
27 // the user when resolving the value of the parameter with the
30 #if BOOST_WORKAROUND(__EDG_VERSION__, <= 300)
31 // These compilers need a little extra help with overload
32 // resolution; we have empty_arg_list's operator[] accept a base
33 // class to make that overload less preferable.
34 template <class KW, class DefaultComputer>
35 struct lazy_default_base
37 lazy_default_base(DefaultComputer const& x)
40 DefaultComputer const& compute_default;
43 template <class KW, class DefaultComputer>
45 : lazy_default_base<KW,DefaultComputer>
47 lazy_default(DefaultComputer const & x)
48 : lazy_default_base<KW,DefaultComputer>(x)
51 # define BOOST_PARAMETER_lazy_default_fallback lazy_default_base
53 template <class KW, class DefaultComputer>
56 lazy_default(const DefaultComputer& x)
59 DefaultComputer const& compute_default;
61 # define BOOST_PARAMETER_lazy_default_fallback lazy_default
64 }}} // namespace boost::parameter::aux
66 #endif // DEFAULT_050329_HPP