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259 lines
7.5 KiB
259 lines
7.5 KiB
/////////////////////////////////////////////////////////////////////////////// |
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// static.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_STATIC_HPP_EAN_10_04_2005 |
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#define BOOST_XPRESSIVE_DETAIL_STATIC_STATIC_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/mpl/assert.hpp> |
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#include <boost/xpressive/detail/detail_fwd.hpp> |
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#include <boost/xpressive/detail/core/state.hpp> |
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#include <boost/xpressive/detail/core/linker.hpp> |
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#include <boost/xpressive/detail/core/peeker.hpp> |
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#include <boost/xpressive/detail/static/placeholders.hpp> |
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#include <boost/xpressive/detail/utility/width.hpp> |
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// Random thoughts: |
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// - must support indirect repeat counts {$n,$m} |
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// - add ws to eat whitespace (make *ws illegal) |
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// - a{n,m} -> repeat<n,m>(a) |
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// - a{$n,$m} -> repeat(n,m)(a) |
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// - add nil to match nothing |
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// - instead of s1, s2, etc., how about s[1], s[2], etc.? Needlessly verbose? |
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namespace boost { namespace xpressive { namespace detail |
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{ |
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/////////////////////////////////////////////////////////////////////////////// |
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// stacked_xpression |
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// |
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template<typename Top, typename Next> |
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struct stacked_xpression |
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: Next |
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{ |
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// match |
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// delegates to Next |
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template<typename BidiIter> |
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bool match(match_state<BidiIter> &state) const |
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{ |
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return static_cast<Next const *>(this)-> |
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BOOST_NESTED_TEMPLATE push_match<Top>(state); |
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} |
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// top_match |
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// jump back to the xpression on top of the xpression stack, |
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// and keep the xpression on the stack. |
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template<typename BidiIter> |
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static bool top_match(match_state<BidiIter> &state, void const *top) |
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{ |
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return static_cast<Top const *>(top)-> |
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BOOST_NESTED_TEMPLATE push_match<Top>(state); |
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} |
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// pop_match |
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// jump back to the xpression on top of the xpression stack, |
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// pop the xpression off the stack. |
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template<typename BidiIter> |
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static bool pop_match(match_state<BidiIter> &state, void const *top) |
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{ |
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return static_cast<Top const *>(top)->match(state); |
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} |
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// skip_match |
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// pop the xpression off the top of the stack and ignore it; call |
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// match on next. |
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template<typename BidiIter> |
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bool skip_match(match_state<BidiIter> &state) const |
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{ |
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// could be static_xpression::skip_impl or stacked_xpression::skip_impl |
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// depending on if there is 1 or more than 1 xpression on the |
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// xpression stack |
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return Top::skip_impl(*static_cast<Next const *>(this), state); |
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} |
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//protected: |
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// skip_impl |
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// implementation of skip_match. |
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template<typename That, typename BidiIter> |
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static bool skip_impl(That const &that, match_state<BidiIter> &state) |
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{ |
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return that.BOOST_NESTED_TEMPLATE push_match<Top>(state); |
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} |
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}; |
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/////////////////////////////////////////////////////////////////////////////// |
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// stacked_xpression_cast |
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// |
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template<typename Top, typename Next> |
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inline stacked_xpression<Top, Next> const &stacked_xpression_cast(Next const &next) |
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{ |
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// NOTE: this is a little white lie. The "next" object doesn't really have |
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// the type to which we're casting it. It is harmless, though. We are only using |
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// the cast to decorate the next object with type information. It is done |
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// this way to save stack space. |
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BOOST_MPL_ASSERT_RELATION(sizeof(stacked_xpression<Top, Next>), ==, sizeof(Next)); |
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return *static_cast<stacked_xpression<Top, Next> const *>(&next); |
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} |
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/////////////////////////////////////////////////////////////////////////////// |
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// static_xpression |
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// |
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template<typename Matcher, typename Next> |
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struct static_xpression |
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: Matcher |
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{ |
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Next next_; |
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BOOST_STATIC_CONSTANT(bool, pure = Matcher::pure && Next::pure); |
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BOOST_STATIC_CONSTANT( |
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std::size_t |
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, width = |
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Matcher::width != unknown_width::value && Next::width != unknown_width::value |
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? Matcher::width + Next::width |
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: unknown_width::value |
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); |
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static_xpression(Matcher const &matcher = Matcher(), Next const &next = Next()) |
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: Matcher(matcher) |
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, next_(next) |
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{ |
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} |
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// match |
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// delegates to the Matcher |
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template<typename BidiIter> |
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bool match(match_state<BidiIter> &state) const |
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{ |
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return this->Matcher::match(state, this->next_); |
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} |
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// push_match |
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// call match on this, but also push "Top" onto the xpression |
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// stack so we know what we are jumping back to later. |
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template<typename Top, typename BidiIter> |
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bool push_match(match_state<BidiIter> &state) const |
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{ |
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return this->Matcher::match(state, stacked_xpression_cast<Top>(this->next_)); |
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} |
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// skip_impl |
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// implementation of skip_match, called from stacked_xpression::skip_match |
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template<typename That, typename BidiIter> |
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static bool skip_impl(That const &that, match_state<BidiIter> &state) |
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{ |
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return that.match(state); |
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} |
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// for linking a compiled regular xpression |
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template<typename Char> |
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void link(xpression_linker<Char> &linker) const |
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{ |
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linker.accept(*static_cast<Matcher const *>(this), &this->next_); |
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this->next_.link(linker); |
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} |
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// for building a lead-follow |
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template<typename Char> |
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void peek(xpression_peeker<Char> &peeker) const |
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{ |
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this->peek_next_(peeker.accept(*static_cast<Matcher const *>(this)), peeker); |
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} |
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// for getting xpression width |
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detail::width get_width() const |
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{ |
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return this->get_width_(mpl::size_t<width>()); |
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} |
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private: |
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static_xpression &operator =(static_xpression const &); |
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template<typename Char> |
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void peek_next_(mpl::true_, xpression_peeker<Char> &peeker) const |
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{ |
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this->next_.peek(peeker); |
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} |
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template<typename Char> |
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void peek_next_(mpl::false_, xpression_peeker<Char> &) const |
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{ |
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// no-op |
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} |
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template<std::size_t Width> |
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detail::width get_width_(mpl::size_t<Width>) const |
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{ |
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return Width; |
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} |
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detail::width get_width_(unknown_width) const |
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{ |
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// Should only be called in contexts where the width is |
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// known to be fixed. |
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return this->Matcher::get_width() + this->next_.get_width(); |
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} |
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}; |
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/////////////////////////////////////////////////////////////////////////////// |
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// make_static |
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// |
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template<typename Matcher> |
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inline static_xpression<Matcher> const |
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make_static(Matcher const &matcher) |
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{ |
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return static_xpression<Matcher>(matcher); |
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} |
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template<typename Matcher, typename Next> |
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inline static_xpression<Matcher, Next> const |
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make_static(Matcher const &matcher, Next const &next) |
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{ |
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return static_xpression<Matcher, Next>(matcher, next); |
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} |
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/////////////////////////////////////////////////////////////////////////////// |
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// no_next |
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// |
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struct no_next |
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{ |
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BOOST_STATIC_CONSTANT(std::size_t, width = 0); |
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BOOST_STATIC_CONSTANT(bool, pure = true); |
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template<typename Char> |
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void link(xpression_linker<Char> &) const |
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{ |
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} |
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template<typename Char> |
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void peek(xpression_peeker<Char> &peeker) const |
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{ |
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peeker.fail(); |
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} |
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detail::width get_width() const |
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{ |
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return 0; |
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} |
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}; |
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/////////////////////////////////////////////////////////////////////////////// |
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// get_mark_number |
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// |
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inline int get_mark_number(basic_mark_tag const &mark) |
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{ |
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return proto::value(mark).mark_number_; |
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} |
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}}} // namespace boost::xpressive::detail |
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#endif
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