ceph/src/boost/libs/xpressive/include/boost/xpressive/detail/static/is_pure.hpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // is_pure.hpp
   3 //
   4 //  Copyright 2008 Eric Niebler. Distributed under the Boost
   5 //  Software License, Version 1.0. (See accompanying file
   6 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7
   8 #ifndef BOOST_XPRESSIVE_DETAIL_STATIC_IS_PURE_HPP_EAN_10_04_2005
   9 #define BOOST_XPRESSIVE_DETAIL_STATIC_IS_PURE_HPP_EAN_10_04_2005
  10
  11 // MS compatible compilers support #pragma once
  12 #if defined(_MSC_VER)
  13 # pragma once
  14 #endif
  15
  16 #include <boost/ref.hpp>
  17 #include <boost/mpl/and.hpp>
  18 #include <boost/mpl/bool.hpp>
  19 #include <boost/mpl/assert.hpp>
  20 #include <boost/mpl/not_equal_to.hpp>
  21 #include <boost/xpressive/detail/detail_fwd.hpp>
  22 #include <boost/xpressive/detail/static/width_of.hpp>
  23
  24 namespace boost { namespace xpressive { namespace detail
  25 {
  26     ///////////////////////////////////////////////////////////////////////////////
  27     // use_simple_repeat_terminal
  28     //
  29     template<typename Expr, typename Char, bool IsXpr = is_xpr<Expr>::value>
  30     struct use_simple_repeat_terminal
  31       : mpl::bool_<
  32             Expr::quant == quant_fixed_width
  33         || (Expr::width != unknown_width::value && Expr::pure)
  34         >
  35     {};
  36
  37     template<typename Expr, typename Char>
  38     struct use_simple_repeat_terminal<Expr, Char, false>
  39       : mpl::true_              // char literals, string literals, etc.
  40     {};
  41
  42     template<typename BidiIter, typename Char>
  43     struct use_simple_repeat_terminal<tracking_ptr<regex_impl<BidiIter> >, Char, false>
  44       : mpl::false_             // basic_regex
  45     {};
  46
  47     template<typename BidiIter, typename Char>
  48     struct use_simple_repeat_terminal<reference_wrapper<basic_regex<BidiIter> >, Char, false>
  49       : mpl::false_             // basic_regex
  50     {};
  51
  52     template<typename BidiIter, typename Char>
  53     struct use_simple_repeat_terminal<reference_wrapper<basic_regex<BidiIter> const>, Char, false>
  54       : mpl::false_             // basic_regex
  55     {};
  56
  57     ///////////////////////////////////////////////////////////////////////////////
  58     // use_simple_repeat_
  59     //
  60     template<typename Expr, typename Char, typename Tag = typename Expr::proto_tag>
  61     struct use_simple_repeat_
  62     {};
  63
  64     template<typename Expr, typename Char>
  65     struct use_simple_repeat_<Expr, Char, proto::tag::terminal>
  66       : use_simple_repeat_terminal<typename proto::result_of::value<Expr>::type, Char>
  67     {};
  68
  69     template<typename Expr, typename Char>
  70     struct use_simple_repeat_<Expr, Char, proto::tag::shift_right>
  71       : mpl::and_<
  72             use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
  73           , use_simple_repeat_<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char>
  74         >
  75     {};
  76
  77     template<typename Expr, typename Char>
  78     struct use_simple_repeat_<Expr, Char, proto::tag::bitwise_or>
  79       : mpl::and_<
  80             mpl::not_equal_to<unknown_width, width_of<Expr, Char> >
  81           , use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
  82           , use_simple_repeat_<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char>
  83         >
  84     {};
  85
  86     template<typename Left>
  87     struct use_simple_repeat_assign
  88     {};
  89
  90     template<>
  91     struct use_simple_repeat_assign<mark_placeholder>
  92       : mpl::false_
  93     {};
  94
  95     template<>
  96     struct use_simple_repeat_assign<set_initializer>
  97       : mpl::true_
  98     {};
  99
 100     template<typename Nbr>
 101     struct use_simple_repeat_assign<attribute_placeholder<Nbr> >
 102       : mpl::false_
 103     {};
 104
 105     // either (s1 = ...) or (a1 = ...) or (set = ...)
 106     template<typename Expr, typename Char>
 107     struct use_simple_repeat_<Expr, Char, proto::tag::assign>
 108       : use_simple_repeat_assign<
 109             typename proto::result_of::value<
 110                 typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr
 111             >::type
 112         >
 113     {};
 114
 115     template<typename Expr, typename Char>
 116     struct use_simple_repeat_<Expr, Char, modifier_tag>
 117       : use_simple_repeat_<typename remove_reference<typename Expr::proto_child1>::type::proto_base_expr, Char>
 118     {};
 119
 120     template<typename Expr, typename Char>
 121     struct use_simple_repeat_<Expr, Char, lookahead_tag>
 122       : mpl::false_
 123     {};
 124
 125     template<typename Expr, typename Char>
 126     struct use_simple_repeat_<Expr, Char, lookbehind_tag>
 127       : mpl::false_
 128     {};
 129
 130     template<typename Expr, typename Char>
 131     struct use_simple_repeat_<Expr, Char, keeper_tag>
 132       : mpl::false_
 133     {};
 134
 135     // when complementing a set or an assertion, the purity is that of the set (true) or the assertion
 136     template<typename Expr, typename Char>
 137     struct use_simple_repeat_<Expr, Char, proto::tag::complement>
 138       : use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
 139     {};
 140
 141     // The comma is used in list-initialized sets, which are pure
 142     template<typename Expr, typename Char>
 143     struct use_simple_repeat_<Expr, Char, proto::tag::comma>
 144       : mpl::true_
 145     {};
 146
 147     // The subscript operator[] is used for sets, as in set['a' | range('b','h')]
 148     // It is also used for actions, which by definition have side-effects and thus are impure
 149     template<typename Expr, typename Char, typename Left>
 150     struct use_simple_repeat_subscript
 151       : mpl::false_
 152     {};
 153
 154     template<typename Expr, typename Char>
 155     struct use_simple_repeat_subscript<Expr, Char, set_initializer_type>
 156       : mpl::true_
 157     {};
 158
 159     template<typename Expr, typename Char>
 160     struct use_simple_repeat_<Expr, Char, proto::tag::subscript>
 161       : use_simple_repeat_subscript<Expr, Char, typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr>
 162     {};
 163
 164     // Quantified expressions are variable-width and cannot use the simple quantifier
 165     template<typename Expr, typename Char>
 166     struct use_simple_repeat_<Expr, Char, proto::tag::unary_plus>
 167       : mpl::false_
 168     {};
 169
 170     template<typename Expr, typename Char>
 171     struct use_simple_repeat_<Expr, Char, proto::tag::dereference>
 172       : mpl::false_
 173     {};
 174
 175     template<typename Expr, typename Char>
 176     struct use_simple_repeat_<Expr, Char, proto::tag::logical_not>
 177       : mpl::false_
 178     {};
 179
 180     template<typename Expr, typename Char, uint_t Min, uint_t Max>
 181     struct use_simple_repeat_<Expr, Char, generic_quant_tag<Min, Max> >
 182       : mpl::false_
 183     {};
 184
 185     template<typename Expr, typename Char, uint_t Count>
 186     struct use_simple_repeat_<Expr, Char, generic_quant_tag<Count, Count> >
 187       : use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
 188     {};
 189
 190     template<typename Expr, typename Char>
 191     struct use_simple_repeat_<Expr, Char, proto::tag::negate>
 192       : use_simple_repeat_<typename remove_reference<typename Expr::proto_child0>::type::proto_base_expr, Char>
 193     {};
 194
 195     ///////////////////////////////////////////////////////////////////////////////
 196     // use_simple_repeat
 197     //
 198     template<typename Expr, typename Char>
 199     struct use_simple_repeat
 200       : use_simple_repeat_<Expr, Char>
 201     {
 202         // should never try to repeat something of 0-width
 203         BOOST_MPL_ASSERT_RELATION(0, !=, (width_of<Expr, Char>::value));
 204     };
 205
 206     template<typename Expr, typename Char>
 207     struct use_simple_repeat<Expr &, Char>
 208       : use_simple_repeat_<Expr, Char>
 209     {
 210         // should never try to repeat something of 0-width
 211         BOOST_MPL_ASSERT_RELATION(0, !=, (width_of<Expr, Char>::value));
 212     };
 213
 214 }}} // namespace boost::xpressive::detail
 215
 216 #endif