| .. Metafunctions/Invocation//unpack_args |30 |
| |
| unpack_args |
| =========== |
| |
| Synopsis |
| -------- |
| |
| .. parsed-literal:: |
| |
| template< |
| typename F |
| > |
| struct unpack_args |
| { |
| // |unspecified| |
| // |...| |
| }; |
| |
| |
| Description |
| ----------- |
| |
| A higher-order primitive transforming an *n*-ary |Lambda Expression| ``F`` into |
| an unary |Metafunction Class| ``g`` accepting a single sequence of *n* arguments. |
| |
| |
| Header |
| ------ |
| |
| .. parsed-literal:: |
| |
| #include <boost/mpl/unpack_args.hpp> |
| |
| |
| Model of |
| -------- |
| |
| |Metafunction Class| |
| |
| |
| Parameters |
| ---------- |
| |
| +---------------+-----------------------+-------------------------------------------+ |
| | Parameter | Requirement | Description | |
| +===============+=======================+===========================================+ |
| | ``F`` | |Lambda Expression| | A lambda expression to adopt. | |
| +---------------+-----------------------+-------------------------------------------+ |
| |
| |
| Expression semantics |
| -------------------- |
| |
| For an arbitrary |Lambda Expression| ``f``, and arbitrary types |a1...an|: |
| |
| |
| .. parsed-literal:: |
| |
| typedef unpack_args<f> g; |
| |
| :Return type: |
| |Metafunction Class|. |
| |
| :Semantics: |
| ``g`` is a unary |Metafunction Class| such that |
| |
| .. parsed-literal:: |
| |
| apply_wrap\ *n*\ < g, vector<a1,\ |...|\ a\ *n*\ > >::type |
| |
| is identical to |
| |
| .. parsed-literal:: |
| |
| apply<F,a1,\ |...|\ a\ *n*\ >::type |
| |
| |
| Example |
| ------- |
| |
| .. parsed-literal:: |
| |
| BOOST_MPL_ASSERT(( apply< |
| unpack_args< is_same<_1,_2> > |
| , vector<int,int> |
| > )); |
| |
| |
| See also |
| -------- |
| |
| |Metafunctions|, |Lambda Expression|, |Metafunction Class|, |apply|, |apply_wrap|, |bind| |
| |
| |
| .. copyright:: Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams |
| 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) |
