///////////////////////////////////////////////////////////////////////////////
|
// predicate_matcher.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_CORE_MATCHER_PREDICATE_MATCHER_HPP_EAN_03_22_2007
|
#define BOOST_XPRESSIVE_DETAIL_CORE_MATCHER_PREDICATE_MATCHER_HPP_EAN_03_22_2007
|
|
// MS compatible compilers support #pragma once
|
#if defined(_MSC_VER)
|
# pragma once
|
#endif
|
|
#include <boost/mpl/not.hpp>
|
#include <boost/mpl/placeholders.hpp>
|
#include <boost/xpressive/detail/detail_fwd.hpp>
|
#include <boost/xpressive/detail/core/quant_style.hpp>
|
#include <boost/xpressive/detail/core/matcher/action_matcher.hpp>
|
#include <boost/xpressive/detail/core/state.hpp>
|
#include <boost/proto/core.hpp>
|
|
namespace boost { namespace xpressive { namespace detail
|
{
|
///////////////////////////////////////////////////////////////////////////////
|
// predicate_context
|
//
|
template<typename BidiIter>
|
struct predicate_context
|
{
|
explicit predicate_context(int sub, sub_match_impl<BidiIter> const *sub_matches, action_args_type *action_args)
|
: sub_(sub)
|
, sub_matches_(sub_matches)
|
, action_args_(action_args)
|
{}
|
|
action_args_type const &args() const
|
{
|
return *this->action_args_;
|
}
|
|
// eval_terminal
|
template<typename Expr, typename Arg>
|
struct eval_terminal
|
: proto::default_eval<Expr, predicate_context const>
|
{};
|
|
template<typename Expr, typename Arg>
|
struct eval_terminal<Expr, reference_wrapper<Arg> >
|
{
|
typedef Arg &result_type;
|
result_type operator()(Expr &expr, predicate_context const &) const
|
{
|
return proto::value(expr).get();
|
}
|
};
|
|
template<typename Expr>
|
struct eval_terminal<Expr, any_matcher>
|
{
|
typedef sub_match<BidiIter> const &result_type;
|
result_type operator()(Expr &, predicate_context const &ctx) const
|
{
|
return ctx.sub_matches_[ctx.sub_];
|
}
|
};
|
|
template<typename Expr>
|
struct eval_terminal<Expr, mark_placeholder>
|
{
|
typedef sub_match<BidiIter> const &result_type;
|
result_type operator()(Expr &expr, predicate_context const &ctx) const
|
{
|
return ctx.sub_matches_[proto::value(expr).mark_number_];
|
}
|
};
|
|
template<typename Expr, typename Type, typename Int>
|
struct eval_terminal<Expr, action_arg<Type, Int> >
|
{
|
typedef typename action_arg<Type, Int>::reference result_type;
|
result_type operator()(Expr &expr, predicate_context const &ctx) const
|
{
|
action_args_type::const_iterator where_ = ctx.args().find(&typeid(proto::value(expr)));
|
if(where_ == ctx.args().end())
|
{
|
BOOST_THROW_EXCEPTION(
|
regex_error(
|
regex_constants::error_badarg
|
, "An argument to an action was unspecified"
|
)
|
);
|
}
|
return proto::value(expr).cast(where_->second);
|
}
|
};
|
|
// eval
|
template<typename Expr, typename Tag = typename Expr::proto_tag>
|
struct eval
|
: proto::default_eval<Expr, predicate_context const>
|
{};
|
|
template<typename Expr>
|
struct eval<Expr, proto::tag::terminal>
|
: eval_terminal<Expr, typename proto::result_of::value<Expr>::type>
|
{};
|
|
#if BOOST_VERSION >= 103500
|
template<typename Expr>
|
struct eval<Expr, proto::tag::mem_ptr>
|
: mem_ptr_eval<Expr, predicate_context const>
|
{};
|
#endif
|
|
int sub_;
|
sub_match_impl<BidiIter> const *sub_matches_;
|
action_args_type *action_args_;
|
};
|
|
///////////////////////////////////////////////////////////////////////////////
|
// AssertionFunctor
|
//
|
struct AssertionFunctor
|
: proto::function<
|
proto::terminal<check_tag>
|
, proto::terminal<proto::_>
|
>
|
{};
|
|
///////////////////////////////////////////////////////////////////////////////
|
// predicate_matcher
|
//
|
template<typename Predicate>
|
struct predicate_matcher
|
: quant_style_assertion
|
{
|
int sub_;
|
Predicate predicate_;
|
|
predicate_matcher(Predicate const &pred, int sub)
|
: sub_(sub)
|
, predicate_(pred)
|
{
|
}
|
|
template<typename BidiIter, typename Next>
|
bool match(match_state<BidiIter> &state, Next const &next) const
|
{
|
// Predicate is check(assertion), where assertion can be
|
// a lambda or a function object.
|
return this->match_(state, next, proto::matches<Predicate, AssertionFunctor>());
|
}
|
|
private:
|
template<typename BidiIter, typename Next>
|
bool match_(match_state<BidiIter> &state, Next const &next, mpl::true_) const
|
{
|
sub_match<BidiIter> const &sub = state.sub_match(this->sub_);
|
return proto::value(proto::child_c<1>(this->predicate_))(sub) && next.match(state);
|
}
|
|
template<typename BidiIter, typename Next>
|
bool match_(match_state<BidiIter> &state, Next const &next, mpl::false_) const
|
{
|
predicate_context<BidiIter> ctx(this->sub_, state.sub_matches_, state.action_args_);
|
return proto::eval(proto::child_c<1>(this->predicate_), ctx) && next.match(state);
|
}
|
};
|
|
}}}
|
|
#endif // BOOST_XPRESSIVE_DETAIL_CORE_MATCHER_PREDICATE_MATCHER_HPP_EAN_03_22_2007
|
