compute/lambda/result_of.hpp

0001 //---------------------------------------------------------------------------//
0002 // Copyright (c) 2013 Kyle Lutz <kyle.r.lutz@gmail.com>
0003 //
0004 // Distributed under the Boost Software License, Version 1.0
0005 // See accompanying file LICENSE_1_0.txt or copy at
0006 // http://www.boost.org/LICENSE_1_0.txt
0007 //
0008 // See http://boostorg.github.com/compute for more information.
0009 //---------------------------------------------------------------------------//
0010
0011 #ifndef BOOST_COMPUTE_LAMBDA_RESULT_OF_HPP
0012 #define BOOST_COMPUTE_LAMBDA_RESULT_OF_HPP
0013
0014 #include <boost/mpl/vector.hpp>
0015 #include <boost/proto/proto.hpp>
0016
0017 #include <boost/compute/type_traits/common_type.hpp>
0018
0019 namespace boost {
0020 namespace compute {
0021 namespace lambda {
0022
0023 namespace mpl = boost::mpl;
0024 namespace proto = boost::proto;
0025
0026 // meta-function returning the result type of a lambda expression
0027 template<class Expr,
0028          class Args = void,
0029          class Tags = typename proto::tag_of<Expr>::type>
0030 struct result_of
0031 {
0032 };
0033
0034 // terminals
0035 template<class Expr, class Args>
0036 struct result_of<Expr, Args, proto::tag::terminal>
0037 {
0038     typedef typename proto::result_of::value<Expr>::type type;
0039 };
0040
0041 // binary operators
0042 #define BOOST_COMPUTE_LAMBDA_RESULT_OF_BINARY_OPERATOR(tag) \
0043     template<class Expr, class Args> \
0044     struct result_of<Expr, Args, tag> \
0045     { \
0046         typedef typename proto::result_of::child_c<Expr, 0>::type left; \
0047         typedef typename proto::result_of::child_c<Expr, 1>::type right; \
0048         \
0049         typedef typename boost::common_type< \
0050             typename ::boost::compute::lambda::result_of< \
0051                          left, \
0052                          Args, \
0053                          typename proto::tag_of<left>::type>::type, \
0054             typename ::boost::compute::lambda::result_of< \
0055                          right, \
0056                          Args, \
0057                          typename proto::tag_of<right>::type>::type \
0058          >::type type; \
0059     };
0060
0061 BOOST_COMPUTE_LAMBDA_RESULT_OF_BINARY_OPERATOR(proto::tag::plus)
0062 BOOST_COMPUTE_LAMBDA_RESULT_OF_BINARY_OPERATOR(proto::tag::minus)
0063 BOOST_COMPUTE_LAMBDA_RESULT_OF_BINARY_OPERATOR(proto::tag::multiplies)
0064 BOOST_COMPUTE_LAMBDA_RESULT_OF_BINARY_OPERATOR(proto::tag::divides)
0065 BOOST_COMPUTE_LAMBDA_RESULT_OF_BINARY_OPERATOR(proto::tag::modulus)
0066 BOOST_COMPUTE_LAMBDA_RESULT_OF_BINARY_OPERATOR(proto::tag::bitwise_and)
0067 BOOST_COMPUTE_LAMBDA_RESULT_OF_BINARY_OPERATOR(proto::tag::bitwise_or)
0068 BOOST_COMPUTE_LAMBDA_RESULT_OF_BINARY_OPERATOR(proto::tag::bitwise_xor)
0069
0070 // comparision operators
0071 #define BOOST_COMPUTE_LAMBDA_RESULT_OF_COMPARISON_OPERATOR(tag) \
0072     template<class Expr, class Args> \
0073     struct result_of<Expr, Args, tag> \
0074     { \
0075         typedef bool type; \
0076     };
0077
0078 BOOST_COMPUTE_LAMBDA_RESULT_OF_COMPARISON_OPERATOR(proto::tag::less)
0079 BOOST_COMPUTE_LAMBDA_RESULT_OF_COMPARISON_OPERATOR(proto::tag::greater)
0080 BOOST_COMPUTE_LAMBDA_RESULT_OF_COMPARISON_OPERATOR(proto::tag::less_equal)
0081 BOOST_COMPUTE_LAMBDA_RESULT_OF_COMPARISON_OPERATOR(proto::tag::greater_equal)
0082 BOOST_COMPUTE_LAMBDA_RESULT_OF_COMPARISON_OPERATOR(proto::tag::equal_to)
0083 BOOST_COMPUTE_LAMBDA_RESULT_OF_COMPARISON_OPERATOR(proto::tag::not_equal_to)
0084 BOOST_COMPUTE_LAMBDA_RESULT_OF_COMPARISON_OPERATOR(proto::tag::logical_and)
0085 BOOST_COMPUTE_LAMBDA_RESULT_OF_COMPARISON_OPERATOR(proto::tag::logical_or)
0086
0087 // assignment operator
0088 template<class Expr, class Args>
0089 struct result_of<Expr, Args, proto::tag::assign>
0090 {
0091     typedef typename proto::result_of::child_c<Expr, 0>::type left;
0092     typedef typename proto::result_of::child_c<Expr, 1>::type right;
0093
0094     typedef typename ::boost::compute::lambda::result_of<
0095         right, Args, typename proto::tag_of<right>::type
0096     >::type type;
0097 };
0098
0099 // functions
0100 template<class Expr, class Args>
0101 struct result_of<Expr, Args, proto::tag::function>
0102 {
0103     typedef typename proto::result_of::child_c<Expr, 0>::type func_expr;
0104     typedef typename proto::result_of::value<func_expr>::type func;
0105
0106     typedef typename func::template lambda_result<Expr, Args>::type type;
0107 };
0108
0109 } // end lambda namespace
0110 } // end compute namespace
0111 } // end boost namespace
0112
0113 #endif // BOOST_COMPUTE_LAMBDA_RESULT_OF_HPP