catch_all

Synopsis

template <class E, class Handler>
struct catch_all
{
  // unspecified
};

Description

Evaluates the angle-bracket expression E. When it evaluates to an exception, the value wrapped by exception is passed to the metafunction class Handler and its result is returned by catch_all. Otherwise catch_all returns the result of E.

Header

#include <mpllibs/metamonad/catch_all.hpp>

Expression semantics

For any t angle-bracket expression not evaluating to an instance of exception, u angle-bracket expression evaluating to exception<e> for some e type and g metafunction class taking one argument the following are equivalent:

catch_all<syntax<t>, f>::type
t::type

catch_all<syntax<u>, f>::type
f::type::apply<e>::type

Example

using boost::mpl::int_;
using namespace mpllibs::metamonad::name;

catch_all<
  syntax<may_fail2<may_fail1<int_<13>>>>,
  lambda_c<e, int_<11>>
>::type

Copyright Abel Sinkovics (abel at elte dot hu) 2011. Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt

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