concat_map

Synopsis

template <class List, class F>
struct concat_map
{
  // unspecified
};

Description

concat_map is a metafunction applying the function F on all elements of the sequence List. The result of applying F on an element is expected to be a sequence. These sequences are concatened and that is the result of this operation.

Header

#include <mpllibs/metamonad/concat_map.hpp>

Expression semantics

For any l sequence of n elements and f metafunction taking one argument:

concat_map<l, f>::type

is equivalent to

concat<
  boost::mpl::apply<f, boost::mpl::at_c<l, 0>::type>::type,
  concat<
    boost::mpl::apply<f, boost::mpl::at_c<l, 1>::type>::type,
    // ...
      boost::mpl::apply<f, boost::mpl::at_c<l, n>::type>::type
    // ...
  >::type
>::type

Example

typedef
  concat_map<
    boost::mpl::list<boost::mpl::int_<1>, boost::mpl::int_<2> >,
    lambda_c<t, list<t, t> >
  >::type
  list_of_1_1_2_2;

Copyright Abel Sinkovics (abel at elte dot hu) 2013. 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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