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