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216 lines
7.5 KiB
216 lines
7.5 KiB
/////////////////////////////////////////////////////////////////////////////// |
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// is_pure.hpp |
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// |
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// Copyright 2008 Eric Niebler. Distributed under the Boost |
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// Software License, Version 1.0. (See accompanying file |
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
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#ifndef BOOST_XPRESSIVE_DETAIL_STATIC_IS_PURE_HPP_EAN_10_04_2005 |
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#define BOOST_XPRESSIVE_DETAIL_STATIC_IS_PURE_HPP_EAN_10_04_2005 |
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// MS compatible compilers support #pragma once |
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#if defined(_MSC_VER) && (_MSC_VER >= 1020) |
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# pragma once |
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#endif |
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#include <boost/ref.hpp> |
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#include <boost/mpl/and.hpp> |
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#include <boost/mpl/bool.hpp> |
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#include <boost/mpl/assert.hpp> |
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#include <boost/mpl/not_equal_to.hpp> |
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#include <boost/xpressive/detail/detail_fwd.hpp> |
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#include <boost/xpressive/detail/static/width_of.hpp> |
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namespace boost { namespace xpressive { namespace detail |
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{ |
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/////////////////////////////////////////////////////////////////////////////// |
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// use_simple_repeat_terminal |
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// |
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template<typename Expr, typename Char, bool IsXpr = is_xpr<Expr>::value> |
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struct use_simple_repeat_terminal |
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: mpl::bool_< |
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Expr::quant == quant_fixed_width |
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|| (Expr::width != unknown_width::value && Expr::pure) |
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> |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_terminal<Expr, Char, false> |
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: mpl::true_ // char literals, string literals, etc. |
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{}; |
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template<typename BidiIter, typename Char> |
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struct use_simple_repeat_terminal<tracking_ptr<regex_impl<BidiIter> >, Char, false> |
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: mpl::false_ // basic_regex |
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{}; |
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template<typename BidiIter, typename Char> |
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struct use_simple_repeat_terminal<reference_wrapper<basic_regex<BidiIter> >, Char, false> |
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: mpl::false_ // basic_regex |
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{}; |
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template<typename BidiIter, typename Char> |
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struct use_simple_repeat_terminal<reference_wrapper<basic_regex<BidiIter> const>, Char, false> |
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: mpl::false_ // basic_regex |
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{}; |
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/////////////////////////////////////////////////////////////////////////////// |
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// use_simple_repeat_ |
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// |
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template<typename Expr, typename Char, typename Tag = typename Expr::proto_tag> |
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struct use_simple_repeat_ |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, proto::tag::terminal> |
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: use_simple_repeat_terminal<typename proto::result_of::value<Expr>::type, Char> |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, proto::tag::shift_right> |
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: mpl::and_< |
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use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char> |
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, use_simple_repeat_<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char> |
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> |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, proto::tag::bitwise_or> |
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: mpl::and_< |
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mpl::not_equal_to<unknown_width, width_of<Expr, Char> > |
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, use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char> |
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, use_simple_repeat_<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char> |
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> |
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{}; |
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template<typename Left> |
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struct use_simple_repeat_assign |
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{}; |
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template<> |
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struct use_simple_repeat_assign<mark_placeholder> |
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: mpl::false_ |
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{}; |
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template<> |
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struct use_simple_repeat_assign<set_initializer> |
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: mpl::true_ |
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{}; |
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template<typename Nbr> |
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struct use_simple_repeat_assign<attribute_placeholder<Nbr> > |
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: mpl::false_ |
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{}; |
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// either (s1 = ...) or (a1 = ...) or (set = ...) |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, proto::tag::assign> |
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: use_simple_repeat_assign< |
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typename proto::result_of::value< |
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typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr |
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>::type |
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> |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, modifier_tag> |
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: use_simple_repeat_<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char> |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, lookahead_tag> |
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: mpl::false_ |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, lookbehind_tag> |
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: mpl::false_ |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, keeper_tag> |
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: mpl::false_ |
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{}; |
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// when complementing a set or an assertion, the purity is that of the set (true) or the assertion |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, proto::tag::complement> |
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: use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char> |
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{}; |
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// The comma is used in list-initialized sets, which are pure |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, proto::tag::comma> |
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: mpl::true_ |
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{}; |
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// The subscript operator[] is used for sets, as in set['a' | range('b','h')] |
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// It is also used for actions, which by definition have side-effects and thus are impure |
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template<typename Expr, typename Char, typename Left> |
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struct use_simple_repeat_subscript |
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: mpl::false_ |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_subscript<Expr, Char, set_initializer_type> |
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: mpl::true_ |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, proto::tag::subscript> |
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: use_simple_repeat_subscript<Expr, Char, typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr> |
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{}; |
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// Quantified expressions are variable-width and cannot use the simple quantifier |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, proto::tag::unary_plus> |
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: mpl::false_ |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, proto::tag::dereference> |
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: mpl::false_ |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, proto::tag::logical_not> |
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: mpl::false_ |
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{}; |
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template<typename Expr, typename Char, uint_t Min, uint_t Max> |
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struct use_simple_repeat_<Expr, Char, generic_quant_tag<Min, Max> > |
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: mpl::false_ |
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{}; |
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template<typename Expr, typename Char, uint_t Count> |
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struct use_simple_repeat_<Expr, Char, generic_quant_tag<Count, Count> > |
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: use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char> |
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{}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat_<Expr, Char, proto::tag::negate> |
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: use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char> |
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{}; |
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/////////////////////////////////////////////////////////////////////////////// |
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// use_simple_repeat |
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// |
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template<typename Expr, typename Char> |
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struct use_simple_repeat |
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: use_simple_repeat_<Expr, Char> |
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{ |
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// should never try to repeat something of 0-width |
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BOOST_MPL_ASSERT_RELATION(0, !=, (width_of<Expr, Char>::value)); |
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}; |
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template<typename Expr, typename Char> |
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struct use_simple_repeat<Expr &, Char> |
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: use_simple_repeat_<Expr, Char> |
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{ |
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// should never try to repeat something of 0-width |
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BOOST_MPL_ASSERT_RELATION(0, !=, (width_of<Expr, Char>::value)); |
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}; |
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}}} // namespace boost::xpressive::detail |
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#endif
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