Chris@16: ///////////////////////////////////////////////////////////////////////////////
Chris@16: // is_pure.hpp
Chris@16: //
Chris@16: //  Copyright 2008 Eric Niebler. Distributed under the Boost
Chris@16: //  Software License, Version 1.0. (See accompanying file
Chris@16: //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_XPRESSIVE_DETAIL_STATIC_IS_PURE_HPP_EAN_10_04_2005
Chris@16: #define BOOST_XPRESSIVE_DETAIL_STATIC_IS_PURE_HPP_EAN_10_04_2005
Chris@16: 
Chris@16: // MS compatible compilers support #pragma once
Chris@101: #if defined(_MSC_VER)
Chris@16: # pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/ref.hpp>
Chris@16: #include <boost/mpl/and.hpp>
Chris@16: #include <boost/mpl/bool.hpp>
Chris@16: #include <boost/mpl/assert.hpp>
Chris@16: #include <boost/mpl/not_equal_to.hpp>
Chris@16: #include <boost/xpressive/detail/detail_fwd.hpp>
Chris@16: #include <boost/xpressive/detail/static/width_of.hpp>
Chris@16: 
Chris@16: namespace boost { namespace xpressive { namespace detail
Chris@16: {
Chris@16:     ///////////////////////////////////////////////////////////////////////////////
Chris@16:     // use_simple_repeat_terminal
Chris@16:     //
Chris@16:     template<typename Expr, typename Char, bool IsXpr = is_xpr<Expr>::value>
Chris@16:     struct use_simple_repeat_terminal
Chris@16:       : mpl::bool_<
Chris@16:             Expr::quant == quant_fixed_width
Chris@16:         || (Expr::width != unknown_width::value && Expr::pure)
Chris@16:         >
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_terminal<Expr, Char, false>
Chris@16:       : mpl::true_              // char literals, string literals, etc.
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename BidiIter, typename Char>
Chris@16:     struct use_simple_repeat_terminal<tracking_ptr<regex_impl<BidiIter> >, Char, false>
Chris@16:       : mpl::false_             // basic_regex
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename BidiIter, typename Char>
Chris@16:     struct use_simple_repeat_terminal<reference_wrapper<basic_regex<BidiIter> >, Char, false>
Chris@16:       : mpl::false_             // basic_regex
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename BidiIter, typename Char>
Chris@16:     struct use_simple_repeat_terminal<reference_wrapper<basic_regex<BidiIter> const>, Char, false>
Chris@16:       : mpl::false_             // basic_regex
Chris@16:     {};
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////////
Chris@16:     // use_simple_repeat_
Chris@16:     //
Chris@16:     template<typename Expr, typename Char, typename Tag = typename Expr::proto_tag>
Chris@16:     struct use_simple_repeat_
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, proto::tag::terminal>
Chris@16:       : use_simple_repeat_terminal<typename proto::result_of::value<Expr>::type, Char>
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, proto::tag::shift_right>
Chris@16:       : mpl::and_<
Chris@16:             use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
Chris@16:           , use_simple_repeat_<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char>
Chris@16:         >
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, proto::tag::bitwise_or>
Chris@16:       : mpl::and_<
Chris@16:             mpl::not_equal_to<unknown_width, width_of<Expr, Char> >
Chris@16:           , use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
Chris@16:           , use_simple_repeat_<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char>
Chris@16:         >
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Left>
Chris@16:     struct use_simple_repeat_assign
Chris@16:     {};
Chris@16: 
Chris@16:     template<>
Chris@16:     struct use_simple_repeat_assign<mark_placeholder>
Chris@16:       : mpl::false_
Chris@16:     {};
Chris@16: 
Chris@16:     template<>
Chris@16:     struct use_simple_repeat_assign<set_initializer>
Chris@16:       : mpl::true_
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Nbr>
Chris@16:     struct use_simple_repeat_assign<attribute_placeholder<Nbr> >
Chris@16:       : mpl::false_
Chris@16:     {};
Chris@16: 
Chris@16:     // either (s1 = ...) or (a1 = ...) or (set = ...)
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, proto::tag::assign>
Chris@16:       : use_simple_repeat_assign<
Chris@16:             typename proto::result_of::value<
Chris@16:                 typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr
Chris@16:             >::type
Chris@16:         >
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, modifier_tag>
Chris@16:       : use_simple_repeat_<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char>
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, lookahead_tag>
Chris@16:       : mpl::false_
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, lookbehind_tag>
Chris@16:       : mpl::false_
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, keeper_tag>
Chris@16:       : mpl::false_
Chris@16:     {};
Chris@16: 
Chris@16:     // when complementing a set or an assertion, the purity is that of the set (true) or the assertion
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, proto::tag::complement>
Chris@16:       : use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
Chris@16:     {};
Chris@16: 
Chris@16:     // The comma is used in list-initialized sets, which are pure
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, proto::tag::comma>
Chris@16:       : mpl::true_
Chris@16:     {};
Chris@16: 
Chris@16:     // The subscript operator[] is used for sets, as in set['a' | range('b','h')]
Chris@16:     // It is also used for actions, which by definition have side-effects and thus are impure
Chris@16:     template<typename Expr, typename Char, typename Left>
Chris@16:     struct use_simple_repeat_subscript
Chris@16:       : mpl::false_
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_subscript<Expr, Char, set_initializer_type>
Chris@16:       : mpl::true_
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, proto::tag::subscript>
Chris@16:       : use_simple_repeat_subscript<Expr, Char, typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr>
Chris@16:     {};
Chris@16: 
Chris@16:     // Quantified expressions are variable-width and cannot use the simple quantifier
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, proto::tag::unary_plus>
Chris@16:       : mpl::false_
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, proto::tag::dereference>
Chris@16:       : mpl::false_
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, proto::tag::logical_not>
Chris@16:       : mpl::false_
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char, uint_t Min, uint_t Max>
Chris@16:     struct use_simple_repeat_<Expr, Char, generic_quant_tag<Min, Max> >
Chris@16:       : mpl::false_
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char, uint_t Count>
Chris@16:     struct use_simple_repeat_<Expr, Char, generic_quant_tag<Count, Count> >
Chris@16:       : use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
Chris@16:     {};
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat_<Expr, Char, proto::tag::negate>
Chris@16:       : use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
Chris@16:     {};
Chris@16: 
Chris@16:     ///////////////////////////////////////////////////////////////////////////////
Chris@16:     // use_simple_repeat
Chris@16:     //
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat
Chris@16:       : use_simple_repeat_<Expr, Char>
Chris@16:     {
Chris@16:         // should never try to repeat something of 0-width
Chris@16:         BOOST_MPL_ASSERT_RELATION(0, !=, (width_of<Expr, Char>::value));
Chris@16:     };
Chris@16: 
Chris@16:     template<typename Expr, typename Char>
Chris@16:     struct use_simple_repeat<Expr &, Char>
Chris@16:       : use_simple_repeat_<Expr, Char>
Chris@16:     {
Chris@16:         // should never try to repeat something of 0-width
Chris@16:         BOOST_MPL_ASSERT_RELATION(0, !=, (width_of<Expr, Char>::value));
Chris@16:     };
Chris@16: 
Chris@16: }}} // namespace boost::xpressive::detail
Chris@16: 
Chris@16: #endif