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ext-boost/boost/proto/matches.hpp
Nick Renieris 509da24bc9 Update to Boost 1.71.0
2019-10-26 00:38:21 +03:00

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///////////////////////////////////////////////////////////////////////////////
/// \file matches.hpp
/// Contains definition of matches\<\> metafunction for determining if
/// a given expression matches a given pattern.
//
// 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_PROTO_MATCHES_HPP_EAN_11_03_2006
#define BOOST_PROTO_MATCHES_HPP_EAN_11_03_2006
#include <boost/config.hpp>
#include <boost/detail/workaround.hpp>
#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/arithmetic/dec.hpp>
#include <boost/preprocessor/arithmetic/sub.hpp>
#include <boost/preprocessor/iteration/iterate.hpp>
#include <boost/preprocessor/facilities/intercept.hpp>
#include <boost/preprocessor/punctuation/comma_if.hpp>
#include <boost/preprocessor/repetition/enum.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/preprocessor/repetition/enum_shifted.hpp>
#include <boost/preprocessor/repetition/enum_binary_params.hpp>
#include <boost/preprocessor/repetition/enum_shifted_params.hpp>
#include <boost/preprocessor/repetition/enum_trailing_params.hpp>
#include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>
#include <boost/preprocessor/repetition/repeat.hpp>
#include <boost/config.hpp>
#include <boost/mpl/logical.hpp>
#include <boost/mpl/eval_if.hpp>
#include <boost/proto/detail/template_arity.hpp>
#include <boost/utility/enable_if.hpp>
#if BOOST_WORKAROUND(BOOST_MSVC, == 1310)
#include <boost/type_traits/is_array.hpp>
#endif
#include <boost/type_traits/is_const.hpp>
#include <boost/type_traits/is_convertible.hpp>
#include <boost/type_traits/is_reference.hpp>
#include <boost/type_traits/is_pointer.hpp>
#include <boost/proto/proto_fwd.hpp>
#include <boost/proto/traits.hpp>
#include <boost/proto/transform/when.hpp>
#include <boost/proto/transform/impl.hpp>
#if defined(_MSC_VER)
# pragma warning(push)
# pragma warning(disable:4305) // 'specialization' : truncation from 'const int' to 'bool'
#endif
#define BOOST_PROTO_LOGICAL_typename_G BOOST_PP_ENUM_PARAMS(BOOST_PROTO_MAX_LOGICAL_ARITY, typename G)
#define BOOST_PROTO_LOGICAL_G BOOST_PP_ENUM_PARAMS(BOOST_PROTO_MAX_LOGICAL_ARITY, G)
namespace boost { namespace proto
{
namespace detail
{
template<typename Expr, typename BasicExpr, typename Grammar>
struct matches_;
template<bool B, typename Pred>
struct and_2;
template<typename And, typename Expr, typename State, typename Data>
struct _and_impl;
template<typename T, typename U>
struct array_matches
: mpl::false_
{};
template<typename T, std::size_t M>
struct array_matches<T[M], T *>
: mpl::true_
{};
template<typename T, std::size_t M>
struct array_matches<T[M], T const *>
: mpl::true_
{};
template<typename T, std::size_t M>
struct array_matches<T[M], T[proto::N]>
: mpl::true_
{};
template<typename T, typename U
BOOST_PROTO_TEMPLATE_ARITY_PARAM(long Arity = detail::template_arity<U>::value)
>
struct lambda_matches
: mpl::false_
{};
template<typename T>
struct lambda_matches<T, proto::_ BOOST_PROTO_TEMPLATE_ARITY_PARAM(-1)>
: mpl::true_
{};
template<typename T>
struct lambda_matches<T, T BOOST_PROTO_TEMPLATE_ARITY_PARAM(-1)>
: mpl::true_
{};
template<typename T, std::size_t M, typename U>
struct lambda_matches<T[M], U BOOST_PROTO_TEMPLATE_ARITY_PARAM(-1)>
: array_matches<T[M], U>
{};
template<typename T, std::size_t M>
struct lambda_matches<T[M], _ BOOST_PROTO_TEMPLATE_ARITY_PARAM(-1)>
: mpl::true_
{};
template<typename T, std::size_t M>
struct lambda_matches<T[M], T[M] BOOST_PROTO_TEMPLATE_ARITY_PARAM(-1)>
: mpl::true_
{};
template<template<typename> class T, typename Expr0, typename Grammar0>
struct lambda_matches<T<Expr0>, T<Grammar0> BOOST_PROTO_TEMPLATE_ARITY_PARAM(1) >
: lambda_matches<Expr0, Grammar0>
{};
// vararg_matches_impl
template<typename Args1, typename Back, long From, long To>
struct vararg_matches_impl;
// vararg_matches
template<typename Expr, typename Args1, typename Args2, typename Back, bool Can, bool Zero, typename Void = void>
struct vararg_matches
: mpl::false_
{};
template<typename Expr, typename Args1, typename Args2, typename Back>
struct vararg_matches<Expr, Args1, Args2, Back, true, true, typename Back::proto_is_vararg_>
: matches_<
Expr
, proto::basic_expr<ignore, Args1, Args1::arity>
, proto::basic_expr<ignore, Args2, Args1::arity>
>
{};
template<typename Expr, typename Args1, typename Args2, typename Back>
struct vararg_matches<Expr, Args1, Args2, Back, true, false, typename Back::proto_is_vararg_>
: and_2<
matches_<
Expr
, proto::basic_expr<ignore, Args1, Args2::arity>
, proto::basic_expr<ignore, Args2, Args2::arity>
>::value
, vararg_matches_impl<Args1, typename Back::proto_grammar, Args2::arity + 1, Args1::arity>
>
{};
// How terminal_matches<> handles references and cv-qualifiers.
// The cv and ref matter *only* if the grammar has a top-level ref.
//
// Expr | Grammar | Matches?
// -------------------------------------
// T T yes
// T & T yes
// T const & T yes
// T T & no
// T & T & yes
// T const & T & no
// T T const & no
// T & T const & no
// T const & T const & yes
template<typename T, typename U>
struct is_cv_ref_compatible
: mpl::true_
{};
template<typename T, typename U>
struct is_cv_ref_compatible<T, U &>
: mpl::false_
{};
template<typename T, typename U>
struct is_cv_ref_compatible<T &, U &>
: mpl::bool_<is_const<T>::value == is_const<U>::value>
{};
#if BOOST_WORKAROUND(BOOST_MSVC, == 1310)
// MSVC-7.1 has lots of problems with array types that have been
// deduced. Partially specializing terminal_matches<> on array types
// doesn't seem to work.
template<
typename T
, typename U
, bool B = is_array<BOOST_PROTO_UNCVREF(T)>::value
>
struct terminal_array_matches
: mpl::false_
{};
template<typename T, typename U, std::size_t M>
struct terminal_array_matches<T, U(&)[M], true>
: is_convertible<T, U(&)[M]>
{};
template<typename T, typename U>
struct terminal_array_matches<T, U(&)[proto::N], true>
: is_convertible<T, U *>
{};
template<typename T, typename U>
struct terminal_array_matches<T, U *, true>
: is_convertible<T, U *>
{};
// terminal_matches
template<typename T, typename U>
struct terminal_matches
: mpl::or_<
mpl::and_<
is_cv_ref_compatible<T, U>
, lambda_matches<
BOOST_PROTO_UNCVREF(T)
, BOOST_PROTO_UNCVREF(U)
>
>
, terminal_array_matches<T, U>
>
{};
#else
// terminal_matches
template<typename T, typename U>
struct terminal_matches
: mpl::and_<
is_cv_ref_compatible<T, U>
, lambda_matches<
BOOST_PROTO_UNCVREF(T)
, BOOST_PROTO_UNCVREF(U)
>
>
{};
template<typename T, std::size_t M>
struct terminal_matches<T(&)[M], T(&)[proto::N]>
: mpl::true_
{};
template<typename T, std::size_t M>
struct terminal_matches<T(&)[M], T *>
: mpl::true_
{};
// Avoid ambiguity errors on MSVC
#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1500))
template<typename T, std::size_t M>
struct terminal_matches<T const (&)[M], T const[M]>
: mpl::true_
{};
#endif
#endif
template<typename T>
struct terminal_matches<T, T>
: mpl::true_
{};
template<typename T>
struct terminal_matches<T &, T>
: mpl::true_
{};
template<typename T>
struct terminal_matches<T const &, T>
: mpl::true_
{};
template<typename T>
struct terminal_matches<T, proto::_>
: mpl::true_
{};
template<typename T>
struct terminal_matches<T, exact<T> >
: mpl::true_
{};
template<typename T, typename U>
struct terminal_matches<T, proto::convertible_to<U> >
: is_convertible<T, U>
{};
// matches_
template<typename Expr, typename BasicExpr, typename Grammar>
struct matches_
: mpl::false_
{};
template<typename Expr, typename BasicExpr>
struct matches_< Expr, BasicExpr, proto::_ >
: mpl::true_
{};
template<typename Expr, typename Tag, typename Args1, long N1, typename Args2, long N2>
struct matches_< Expr, proto::basic_expr<Tag, Args1, N1>, proto::basic_expr<Tag, Args2, N2> >
: vararg_matches< Expr, Args1, Args2, typename Args2::back_, (N1+2 > N2), (N2 > N1) >
{};
template<typename Expr, typename Tag, typename Args1, long N1, typename Args2, long N2>
struct matches_< Expr, proto::basic_expr<Tag, Args1, N1>, proto::basic_expr<proto::_, Args2, N2> >
: vararg_matches< Expr, Args1, Args2, typename Args2::back_, (N1+2 > N2), (N2 > N1) >
{};
template<typename Expr, typename Tag, typename Args1, typename Args2>
struct matches_< Expr, proto::basic_expr<Tag, Args1, 0>, proto::basic_expr<Tag, Args2, 0> >
: terminal_matches<typename Args1::child0, typename Args2::child0>
{};
template<typename Expr, typename Tag, typename Args1, typename Args2, long N2>
struct matches_< Expr, proto::basic_expr<Tag, Args1, 0>, proto::basic_expr<proto::_, Args2, N2> >
: mpl::false_
{};
template<typename Expr, typename Tag, typename Args1, typename Args2>
struct matches_< Expr, proto::basic_expr<Tag, Args1, 0>, proto::basic_expr<proto::_, Args2, 0> >
: terminal_matches<typename Args1::child0, typename Args2::child0>
{};
template<typename Expr, typename Tag, typename Args1, typename Args2>
struct matches_< Expr, proto::basic_expr<Tag, Args1, 1>, proto::basic_expr<Tag, Args2, 1> >
: matches_<
typename detail::expr_traits<typename Args1::child0>::value_type::proto_derived_expr
, typename detail::expr_traits<typename Args1::child0>::value_type::proto_grammar
, typename Args2::child0::proto_grammar
>
{};
template<typename Expr, typename Tag, typename Args1, typename Args2>
struct matches_< Expr, proto::basic_expr<Tag, Args1, 1>, proto::basic_expr<proto::_, Args2, 1> >
: matches_<
typename detail::expr_traits<typename Args1::child0>::value_type::proto_derived_expr
, typename detail::expr_traits<typename Args1::child0>::value_type::proto_grammar
, typename Args2::child0::proto_grammar
>
{};
#include <boost/proto/detail/and_n.hpp>
#include <boost/proto/detail/or_n.hpp>
#include <boost/proto/detail/matches_.hpp>
#include <boost/proto/detail/vararg_matches_impl.hpp>
#include <boost/proto/detail/lambda_matches.hpp>
// handle proto::if_
template<typename Expr, typename Tag, typename Args, long Arity, typename If, typename Then, typename Else>
struct matches_<Expr, proto::basic_expr<Tag, Args, Arity>, proto::if_<If, Then, Else> >
: mpl::eval_if_c<
static_cast<bool>(
remove_reference<
typename when<_, If>::template impl<Expr, int, int>::result_type
>::type::value
)
, matches_<Expr, proto::basic_expr<Tag, Args, Arity>, typename Then::proto_grammar>
, matches_<Expr, proto::basic_expr<Tag, Args, Arity>, typename Else::proto_grammar>
>::type
{
typedef
typename mpl::if_c<
static_cast<bool>(
remove_reference<
typename when<_, If>::template impl<Expr, int, int>::result_type
>::type::value
)
, Then
, Else
>::type
which;
};
// handle degenerate cases of proto::or_
template<typename Expr, typename BasicExpr>
struct matches_<Expr, BasicExpr, or_<> >
: mpl::false_
{
typedef not_<_> which;
};
template<typename Expr, typename BasicExpr, typename G0>
struct matches_<Expr, BasicExpr, or_<G0> >
: matches_<Expr, BasicExpr, typename G0::proto_grammar>
{
typedef G0 which;
};
// handle degenerate cases of proto::and_
template<typename Expr, typename BasicExpr>
struct matches_<Expr, BasicExpr, and_<> >
: mpl::true_
{};
template<typename Expr, typename BasicExpr, typename G0>
struct matches_<Expr, BasicExpr, and_<G0> >
: matches_<Expr, BasicExpr, typename G0::proto_grammar>
{};
// handle proto::not_
template<typename Expr, typename BasicExpr, typename Grammar>
struct matches_<Expr, BasicExpr, not_<Grammar> >
: mpl::not_<matches_<Expr, BasicExpr, typename Grammar::proto_grammar> >
{};
// handle proto::switch_
template<typename Expr, typename Tag, typename Args, long Arity, typename Cases, typename Transform>
struct matches_<Expr, proto::basic_expr<Tag, Args, Arity>, switch_<Cases, Transform> >
: matches_<
Expr
, proto::basic_expr<Tag, Args, Arity>
, typename Cases::template case_<
typename when<_,Transform>::template impl<Expr,int,int>::result_type
>::proto_grammar
>
{
typedef
typename Cases::template case_<
typename when<_, Transform>::template impl<Expr, int, int>::result_type
>
which;
};
// handle proto::switch_ with the default Transform for specially for better compile times
template<typename Expr, typename Tag, typename Args, long Arity, typename Cases>
struct matches_<Expr, proto::basic_expr<Tag, Args, Arity>, switch_<Cases> >
: matches_<
Expr
, proto::basic_expr<Tag, Args, Arity>
, typename Cases::template case_<Tag>::proto_grammar
>
{
typedef typename Cases::template case_<Tag> which;
};
}
/// \brief A Boolean metafunction that evaluates whether a given
/// expression type matches a grammar.
///
/// <tt>matches\<Expr,Grammar\></tt> inherits (indirectly) from
/// \c mpl::true_ if <tt>Expr::proto_grammar</tt> matches
/// <tt>Grammar::proto_grammar</tt>, and from \c mpl::false_
/// otherwise.
///
/// Non-terminal expressions are matched against a grammar
/// according to the following rules:
///
/// \li The wildcard pattern, \c _, matches any expression.
/// \li An expression <tt>expr\<AT, listN\<A0,A1,...An\> \></tt>
/// matches a grammar <tt>expr\<BT, listN\<B0,B1,...Bn\> \></tt>
/// if \c BT is \c _ or \c AT, and if \c Ax matches \c Bx for
/// each \c x in <tt>[0,n)</tt>.
/// \li An expression <tt>expr\<AT, listN\<A0,...An,U0,...Um\> \></tt>
/// matches a grammar <tt>expr\<BT, listM\<B0,...Bn,vararg\<V\> \> \></tt>
/// if \c BT is \c _ or \c AT, and if \c Ax matches \c Bx
/// for each \c x in <tt>[0,n)</tt> and if \c Ux matches \c V
/// for each \c x in <tt>[0,m)</tt>.
/// \li An expression \c E matches <tt>or_\<B0,B1,...Bn\></tt> if \c E
/// matches some \c Bx for \c x in <tt>[0,n)</tt>.
/// \li An expression \c E matches <tt>and_\<B0,B1,...Bn\></tt> if \c E
/// matches all \c Bx for \c x in <tt>[0,n)</tt>.
/// \li An expression \c E matches <tt>if_\<T,U,V\></tt> if
/// <tt>boost::result_of\<when\<_,T\>(E,int,int)\>::type::value</tt>
/// is \c true and \c E matches \c U; or, if
/// <tt>boost::result_of\<when\<_,T\>(E,int,int)\>::type::value</tt>
/// is \c false and \c E matches \c V. (Note: \c U defaults to \c _
/// and \c V defaults to \c not_\<_\>.)
/// \li An expression \c E matches <tt>not_\<T\></tt> if \c E does
/// not match \c T.
/// \li An expression \c E matches <tt>switch_\<C,T\></tt> if
/// \c E matches <tt>C::case_\<boost::result_of\<T(E)\>::type\></tt>.
/// (Note: T defaults to <tt>tag_of\<_\>()</tt>.)
///
/// A terminal expression <tt>expr\<AT,term\<A\> \></tt> matches
/// a grammar <tt>expr\<BT,term\<B\> \></tt> if \c BT is \c AT or
/// \c proto::_ and if one of the following is true:
///
/// \li \c B is the wildcard pattern, \c _
/// \li \c A is \c B
/// \li \c A is <tt>B &</tt>
/// \li \c A is <tt>B const &</tt>
/// \li \c B is <tt>exact\<A\></tt>
/// \li \c B is <tt>convertible_to\<X\></tt> and
/// <tt>is_convertible\<A,X\>::value</tt> is \c true.
/// \li \c A is <tt>X[M]</tt> or <tt>X(&)[M]</tt> and
/// \c B is <tt>X[proto::N]</tt>.
/// \li \c A is <tt>X(&)[M]</tt> and \c B is <tt>X(&)[proto::N]</tt>.
/// \li \c A is <tt>X[M]</tt> or <tt>X(&)[M]</tt> and
/// \c B is <tt>X*</tt>.
/// \li \c B lambda-matches \c A (see below).
///
/// A type \c B lambda-matches \c A if one of the following is true:
///
/// \li \c B is \c A
/// \li \c B is the wildcard pattern, \c _
/// \li \c B is <tt>T\<B0,B1,...Bn\></tt> and \c A is
/// <tt>T\<A0,A1,...An\></tt> and for each \c x in
/// <tt>[0,n)</tt>, \c Ax and \c Bx are types
/// such that \c Ax lambda-matches \c Bx
template<typename Expr, typename Grammar>
struct matches
: detail::matches_<
typename Expr::proto_derived_expr
, typename Expr::proto_grammar
, typename Grammar::proto_grammar
>
{};
/// INTERNAL ONLY
///
template<typename Expr, typename Grammar>
struct matches<Expr &, Grammar>
: detail::matches_<
typename Expr::proto_derived_expr
, typename Expr::proto_grammar
, typename Grammar::proto_grammar
>
{};
/// \brief A wildcard grammar element that matches any expression,
/// and a transform that returns the current expression unchanged.
///
/// The wildcard type, \c _, is a grammar element such that
/// <tt>matches\<E,_\>::value</tt> is \c true for any expression
/// type \c E.
///
/// The wildcard can also be used as a stand-in for a template
/// argument when matching terminals. For instance, the following
/// is a grammar that will match any <tt>std::complex\<\></tt>
/// terminal:
///
/// \code
/// BOOST_MPL_ASSERT((
/// matches<
/// terminal<std::complex<double> >::type
/// , terminal<std::complex< _ > >
/// >
/// ));
/// \endcode
///
/// When used as a transform, \c _ returns the current expression
/// unchanged. For instance, in the following, \c _ is used with
/// the \c fold\<\> transform to fold the children of a node:
///
/// \code
/// struct CountChildren
/// : or_<
/// // Terminals have no children
/// when<terminal<_>, mpl::int_<0>()>
/// // Use fold<> to count the children of non-terminals
/// , otherwise<
/// fold<
/// _ // <-- fold the current expression
/// , mpl::int_<0>()
/// , mpl::plus<_state, mpl::int_<1> >()
/// >
/// >
/// >
/// {};
/// \endcode
struct _ : transform<_>
{
typedef _ proto_grammar;
template<typename Expr, typename State, typename Data>
struct impl : transform_impl<Expr, State, Data>
{
typedef Expr result_type;
/// \param expr An expression
/// \return \c e
BOOST_PROTO_RETURN_TYPE_STRICT_LOOSE(result_type, typename impl::expr_param)
operator()(
typename impl::expr_param e
, typename impl::state_param
, typename impl::data_param
) const
{
return e;
}
};
};
namespace detail
{
template<typename Expr, typename State, typename Data>
struct _and_impl<proto::and_<>, Expr, State, Data>
: proto::_::impl<Expr, State, Data>
{};
template<typename G0, typename Expr, typename State, typename Data>
struct _and_impl<proto::and_<G0>, Expr, State, Data>
: proto::when<proto::_, G0>::template impl<Expr, State, Data>
{};
}
/// \brief Inverts the set of expressions matched by a grammar. When
/// used as a transform, \c not_\<\> returns the current expression
/// unchanged.
///
/// If an expression type \c E does not match a grammar \c G, then
/// \c E \e does match <tt>not_\<G\></tt>. For example,
/// <tt>not_\<terminal\<_\> \></tt> will match any non-terminal.
template<typename Grammar>
struct not_ : transform<not_<Grammar> >
{
typedef not_ proto_grammar;
template<typename Expr, typename State, typename Data>
struct impl : transform_impl<Expr, State, Data>
{
typedef Expr result_type;
/// \param e An expression
/// \pre <tt>matches\<Expr,not_\>::value</tt> is \c true.
/// \return \c e
BOOST_PROTO_RETURN_TYPE_STRICT_LOOSE(result_type, typename impl::expr_param)
operator()(
typename impl::expr_param e
, typename impl::state_param
, typename impl::data_param
) const
{
return e;
}
};
};
/// \brief Used to select one grammar or another based on the result
/// of a compile-time Boolean. When used as a transform, \c if_\<\>
/// selects between two transforms based on a compile-time Boolean.
///
/// When <tt>if_\<If,Then,Else\></tt> is used as a grammar, \c If
/// must be a Proto transform and \c Then and \c Else must be grammars.
/// An expression type \c E matches <tt>if_\<If,Then,Else\></tt> if
/// <tt>boost::result_of\<when\<_,If\>(E,int,int)\>::type::value</tt>
/// is \c true and \c E matches \c U; or, if
/// <tt>boost::result_of\<when\<_,If\>(E,int,int)\>::type::value</tt>
/// is \c false and \c E matches \c V.
///
/// The template parameter \c Then defaults to \c _
/// and \c Else defaults to \c not\<_\>, so an expression type \c E
/// will match <tt>if_\<If\></tt> if and only if
/// <tt>boost::result_of\<when\<_,If\>(E,int,int)\>::type::value</tt>
/// is \c true.
///
/// \code
/// // A grammar that only matches integral terminals,
/// // using is_integral<> from Boost.Type_traits.
/// struct IsIntegral
/// : and_<
/// terminal<_>
/// , if_< is_integral<_value>() >
/// >
/// {};
/// \endcode
///
/// When <tt>if_\<If,Then,Else\></tt> is used as a transform, \c If,
/// \c Then and \c Else must be Proto transforms. When applying
/// the transform to an expression \c E, state \c S and data \c V,
/// if <tt>boost::result_of\<when\<_,If\>(E,S,V)\>::type::value</tt>
/// is \c true then the \c Then transform is applied; otherwise
/// the \c Else transform is applied.
///
/// \code
/// // Match a terminal. If the terminal is integral, return
/// // mpl::true_; otherwise, return mpl::false_.
/// struct IsIntegral2
/// : when<
/// terminal<_>
/// , if_<
/// is_integral<_value>()
/// , mpl::true_()
/// , mpl::false_()
/// >
/// >
/// {};
/// \endcode
template<
typename If
, typename Then // = _
, typename Else // = not_<_>
>
struct if_ : transform<if_<If, Then, Else> >
{
typedef if_ proto_grammar;
template<typename Expr, typename State, typename Data>
struct impl : transform_impl<Expr, State, Data>
{
typedef
typename when<_, If>::template impl<Expr, State, Data>::result_type
condition;
typedef
typename mpl::if_c<
static_cast<bool>(remove_reference<condition>::type::value)
, when<_, Then>
, when<_, Else>
>::type
which;
typedef typename which::template impl<Expr, State, Data>::result_type result_type;
/// \param e An expression
/// \param s The current state
/// \param d A data of arbitrary type
/// \return <tt>which::impl<Expr, State, Data>()(e, s, d)</tt>
result_type operator ()(
typename impl::expr_param e
, typename impl::state_param s
, typename impl::data_param d
) const
{
return typename which::template impl<Expr, State, Data>()(e, s, d);
}
};
};
/// \brief For matching one of a set of alternate grammars. Alternates
/// tried in order to avoid ambiguity. When used as a transform, \c or_\<\>
/// applies the transform associated with the first grammar that matches
/// the expression.
///
/// An expression type \c E matches <tt>or_\<B0,B1,...Bn\></tt> if \c E
/// matches any \c Bx for \c x in <tt>[0,n)</tt>.
///
/// When applying <tt>or_\<B0,B1,...Bn\></tt> as a transform with an
/// expression \c e of type \c E, state \c s and data \c d, it is
/// equivalent to <tt>Bx()(e, s, d)</tt>, where \c x is the lowest
/// number such that <tt>matches\<E,Bx\>::value</tt> is \c true.
template<BOOST_PROTO_LOGICAL_typename_G>
struct or_ : transform<or_<BOOST_PROTO_LOGICAL_G> >
{
typedef or_ proto_grammar;
/// \param e An expression
/// \param s The current state
/// \param d A data of arbitrary type
/// \pre <tt>matches\<Expr,or_\>::value</tt> is \c true.
/// \return <tt>which()(e, s, d)</tt>, where <tt>which</tt> is the
/// sub-grammar that matched <tt>Expr</tt>.
template<typename Expr, typename State, typename Data>
struct impl
: detail::matches_<
typename Expr::proto_derived_expr
, typename Expr::proto_grammar
, or_
>::which::template impl<Expr, State, Data>
{};
template<typename Expr, typename State, typename Data>
struct impl<Expr &, State, Data>
: detail::matches_<
typename Expr::proto_derived_expr
, typename Expr::proto_grammar
, or_
>::which::template impl<Expr &, State, Data>
{};
};
/// \brief For matching all of a set of grammars. When used as a
/// transform, \c and_\<\> applies the transforms associated with
/// the each grammar in the set, and returns the result of the last.
///
/// An expression type \c E matches <tt>and_\<B0,B1,...Bn\></tt> if \c E
/// matches all \c Bx for \c x in <tt>[0,n)</tt>.
///
/// When applying <tt>and_\<B0,B1,...Bn\></tt> as a transform with an
/// expression \c e, state \c s and data \c d, it is
/// equivalent to <tt>(B0()(e, s, d),B1()(e, s, d),...Bn()(e, s, d))</tt>.
template<BOOST_PROTO_LOGICAL_typename_G>
struct and_ : transform<and_<BOOST_PROTO_LOGICAL_G> >
{
typedef and_ proto_grammar;
template<typename Expr, typename State, typename Data>
struct impl
: detail::_and_impl<and_, Expr, State, Data>
{};
};
/// \brief For matching one of a set of alternate grammars, which
/// are looked up based on some property of an expression. The
/// property on which to dispatch is specified by the \c Transform
/// template parameter, which defaults to <tt>tag_of\<_\>()</tt>.
/// That is, when the \c Trannsform is not specified, the alternate
/// grammar is looked up using the tag type of the current expression.
///
/// When used as a transform, \c switch_\<\> applies the transform
/// associated with the grammar that matches the expression.
///
/// \note \c switch_\<\> is functionally identical to \c or_\<\> but
/// is often more efficient. It does a fast, O(1) lookup using the
/// result of the specified transform to find a sub-grammar that may
/// potentially match the expression.
///
/// An expression type \c E matches <tt>switch_\<C,T\></tt> if \c E
/// matches <tt>C::case_\<boost::result_of\<T(E)\>::type\></tt>.
///
/// When applying <tt>switch_\<C,T\></tt> as a transform with an
/// expression \c e of type \c E, state \c s of type \S and data
/// \c d of type \c D, it is equivalent to
/// <tt>C::case_\<boost::result_of\<T(E,S,D)\>::type\>()(e, s, d)</tt>.
template<typename Cases, typename Transform>
struct switch_ : transform<switch_<Cases, Transform> >
{
typedef switch_ proto_grammar;
template<typename Expr, typename State, typename Data>
struct impl
: Cases::template case_<
typename when<_, Transform>::template impl<Expr, State, Data>::result_type
>::template impl<Expr, State, Data>
{};
};
/// INTERNAL ONLY (This is merely a compile-time optimization for the common case)
///
template<typename Cases>
struct switch_<Cases> : transform<switch_<Cases> >
{
typedef switch_ proto_grammar;
template<typename Expr, typename State, typename Data>
struct impl
: Cases::template case_<typename Expr::proto_tag>::template impl<Expr, State, Data>
{};
template<typename Expr, typename State, typename Data>
struct impl<Expr &, State, Data>
: Cases::template case_<typename Expr::proto_tag>::template impl<Expr &, State, Data>
{};
};
/// \brief For forcing exact matches of terminal types.
///
/// By default, matching terminals ignores references and
/// cv-qualifiers. For instance, a terminal expression of
/// type <tt>terminal\<int const &\>::type</tt> will match
/// the grammar <tt>terminal\<int\></tt>. If that is not
/// desired, you can force an exact match with
/// <tt>terminal\<exact\<int\> \></tt>. This will only
/// match integer terminals where the terminal is held by
/// value.
template<typename T>
struct exact
{};
/// \brief For matching terminals that are convertible to
/// a type.
///
/// Use \c convertible_to\<\> to match a terminal that is
/// convertible to some type. For example, the grammar
/// <tt>terminal\<convertible_to\<int\> \></tt> will match
/// any terminal whose argument is convertible to an integer.
///
/// \note The trait \c is_convertible\<\> from Boost.Type_traits
/// is used to determinal convertibility.
template<typename T>
struct convertible_to
{};
/// \brief For matching a Grammar to a variable number of
/// sub-expressions.
///
/// An expression type <tt>expr\<AT, listN\<A0,...An,U0,...Um\> \></tt>
/// matches a grammar <tt>expr\<BT, listM\<B0,...Bn,vararg\<V\> \> \></tt>
/// if \c BT is \c _ or \c AT, and if \c Ax matches \c Bx
/// for each \c x in <tt>[0,n)</tt> and if \c Ux matches \c V
/// for each \c x in <tt>[0,m)</tt>.
///
/// For example:
///
/// \code
/// // Match any function call expression, irregardless
/// // of the number of function arguments:
/// struct Function
/// : function< vararg<_> >
/// {};
/// \endcode
///
/// When used as a transform, <tt>vararg\<G\></tt> applies
/// <tt>G</tt>'s transform.
template<typename Grammar>
struct vararg
: Grammar
{
/// INTERNAL ONLY
typedef void proto_is_vararg_;
};
/// INTERNAL ONLY
///
template<BOOST_PROTO_LOGICAL_typename_G>
struct is_callable<or_<BOOST_PROTO_LOGICAL_G> >
: mpl::true_
{};
/// INTERNAL ONLY
///
template<BOOST_PROTO_LOGICAL_typename_G>
struct is_callable<and_<BOOST_PROTO_LOGICAL_G> >
: mpl::true_
{};
/// INTERNAL ONLY
///
template<typename Grammar>
struct is_callable<not_<Grammar> >
: mpl::true_
{};
/// INTERNAL ONLY
///
template<typename If, typename Then, typename Else>
struct is_callable<if_<If, Then, Else> >
: mpl::true_
{};
/// INTERNAL ONLY
///
template<typename Grammar>
struct is_callable<vararg<Grammar> >
: mpl::true_
{};
/// INTERNAL ONLY
///
template<typename Cases, typename Transform>
struct is_callable<switch_<Cases, Transform> >
: mpl::true_
{};
}}
#undef BOOST_PROTO_LOGICAL_typename_G
#undef BOOST_PROTO_LOGICAL_G
#if defined(_MSC_VER)
# pragma warning(pop)
#endif
#endif
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