sample10.cpp

C++的一个好库。。。现在很流行

/*=============================================================================
    Phoenix V1.2.1
    Copyright (c) 2001-2003 Joel de Guzman

    Use, modification and distribution is subject to 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)
==============================================================================*/
#include <vector>
#include <algorithm>
#include <iostream>

#define PHOENIX_LIMIT 5
#include <boost/spirit/phoenix/operators.hpp>
#include <boost/spirit/phoenix/primitives.hpp>
#include <boost/spirit/phoenix/composite.hpp>
#include <boost/spirit/phoenix/special_ops.hpp>
#include <boost/spirit/phoenix/statements.hpp>
#include <boost/spirit/phoenix/functions.hpp>

namespace phoenix {

///////////////////////////////////////////////////////////////////////////////
//
//  local_tuple
//
//      This *is a* tuple like the one we see in TupleT in any actor
//      base class' eval member function. local_tuple should look and
//      feel the same as a tupled-args, that's why it is derived from
//      TupleArgsT. It has an added member, locs which is another tuple
//      where the local variables will be stored. locs is mutable to
//      allow read-write access to our locals regardless of
//      local_tuple's constness (The eval member function accepts it as
//      a const argument).
//
///////////////////////////////////////////////////////////////////////////////
template <typename TupleArgsT, typename TupleLocsT>
struct local_tuple : public TupleArgsT {

    local_tuple(TupleArgsT const& args, TupleLocsT const& locs_)
    :   TupleArgsT(args), locs(locs_) {}

    mutable TupleLocsT locs;
};

///////////////////////////////////////////////////////////////////////////////
//
//  local_var_result
//
//      This is a return type computer. Given a constant integer N, a
//      parent index and a tuple, get the Nth local variable type. The
//      parent index is an integer specifying which parent scope to
//      access; 0==current scope, 1==parent scope, 2==parent's parent
//      scope etc.
//
//      This is a metaprogram with partial specializations. There is a
//      general case, a special case for local_tuples and a terminating
//      special case for local_tuples.
//
//      General case: If TupleT is not really a local_tuple, we just return nil_t.
//
//      local_tuples case:
//          Parent index is 0: We get the Nth local variable.
//          Otherwise: We subclass from local_tuples<N, Parent-1, TupleArgsT>
//
///////////////////////////////////////////////////////////////////////////////
template <int N, int Parent, typename TupleT>
struct local_var_result {

    typedef nil_t type;
};

//////////////////////////////////
template <int N, int Parent, typename TupleArgsT, typename TupleLocsT>
struct local_var_result<N, Parent, local_tuple<TupleArgsT, TupleLocsT> >
:   public local_var_result<N, Parent-1, TupleArgsT> {};

//////////////////////////////////
template <int N, typename TupleArgsT, typename TupleLocsT>
struct local_var_result<N, 0, local_tuple<TupleArgsT, TupleLocsT> > {

    typedef typename tuple_element<N, TupleLocsT>::type& type;

    static type get(local_tuple<TupleArgsT, TupleLocsT> const& tuple)
    { return tuple.locs[tuple_index<N>()]; }
};

///////////////////////////////////////////////////////////////////////////////
//
//  local_var
//
//      This class looks so curiously like the argument class. local_var
//      provides access to the Nth local variable packed in the tuple
//      duo local_tuple above. Parent specifies the Nth parent scope.
//      0==current scope, 1==parent scope, 2==parent's parent scope etc.
//      The member function parent<N>() may be called to provide access
//      to outer scopes.
//
//      Note that the member function eval expects a local_tuple
//      argument. Otherwise there will be acompile-time error. local_var
//      primitives only work within the context of a context_composite
//      (see below).
//
//      Provided are some predefined local_var actors for 0..N local
//      variable access: lvar1..locN.
//
///////////////////////////////////////////////////////////////////////////////
template <int N, int Parent = 0>
struct local_var {

    typedef local_var<N, Parent> self_t;

    template <typename TupleT>
    struct result {

        typedef typename local_var_result<N, Parent, TupleT>::type type;
    };

    template <typename TupleT>
    typename actor_result<self_t, TupleT>::type
    eval(TupleT const& tuple) const
    {
        return local_var_result<N, Parent, TupleT>::get(tuple);
    }

    template <int PIndex>
    actor<local_var<N, Parent+PIndex> >
    parent() const
    {
        return local_var<N, Parent+PIndex>();
    }
};

//////////////////////////////////
namespace locals {

    actor<local_var<0> > const result   = local_var<0>();
    actor<local_var<1> > const lvar1    = local_var<1>();
    actor<local_var<2> > const lvar2    = local_var<2>();
    actor<local_var<3> > const lvar3    = local_var<3>();
    actor<local_var<4> > const lvar4    = local_var<4>();
}









///////////////////////////////////////////////////////////////////////////////
template <int N, int Parent, typename TupleT>
struct local_func_result {

    typedef nil_t type;
};

//////////////////////////////////
template <int N, int Parent, typename TupleArgsT, typename TupleLocsT>
struct local_func_result<N, Parent, local_tuple<TupleArgsT, TupleLocsT> >
:   public local_func_result<N, Parent-1, TupleArgsT> {};

//////////////////////////////////
template <int N, typename TupleArgsT, typename TupleLocsT>
struct local_func_result<N, 0, local_tuple<TupleArgsT, TupleLocsT> > {

    typedef typename actor_result<
        typename tuple_element<N, TupleLocsT>::type,
        local_tuple<TupleArgsT, TupleLocsT>
    >::type type;

    template <typename ArgsT>
    static type eval(local_tuple<ArgsT, TupleLocsT> const& tuple)
    { return tuple.locs[tuple_index<N>()].eval(tuple); }
};








template <
    int N, int Parent,
    typename A0 = nil_t,
    typename A1 = nil_t,
    typename A2 = nil_t,
    typename A3 = nil_t,
    typename A4 = nil_t
>
struct local_function_actor;

//////////////////////////////////
template <int N, int Parent>
struct local_function_base {

    template <typename TupleT>
    struct result {

        typedef typename local_func_result<N, Parent, TupleT>::type type;
    };
};

//////////////////////////////////
template <int N, int Parent>
struct local_function_actor<N, Parent, nil_t, nil_t, nil_t, nil_t, nil_t>
:   public local_function_base<N, Parent> {

    template <typename TupleArgsT, typename TupleLocsT>
    typename local_func_result<
        N, Parent, local_tuple<TupleArgsT, TupleLocsT> >::type
    eval(local_tuple<TupleArgsT, TupleLocsT> const& args) const
    {
        typedef local_tuple<TupleArgsT, TupleLocsT> local_tuple_t;
        typedef tuple<> tuple_t;
        tuple_t local_args;

        local_tuple<tuple_t, TupleLocsT> local_context(local_args, args.locs);
        return local_func_result<
            N, Parent, local_tuple_t>
        ::eval(local_context);
    }
};

//////////////////////////////////
template <int N, int Parent,
    typename A0>
struct local_function_actor<N, Parent, A0, nil_t, nil_t, nil_t, nil_t>
:   public local_function_base<N, Parent> {

    local_function_actor(
        A0 const& _0)
    :   a0(_0) {}

    template <typename TupleArgsT, typename TupleLocsT>
    typename local_func_result<
        N, Parent, local_tuple<TupleArgsT, TupleLocsT> >::type
    eval(local_tuple<TupleArgsT, TupleLocsT> const& args) const
    {
        typedef local_tuple<TupleArgsT, TupleLocsT> local_tuple_t;
        typename actor_result<A0, local_tuple_t>::type r0 = a0.eval(args);

        typedef tuple<
            typename actor_result<A0, local_tuple_t>::type
        > tuple_t;
        tuple_t local_args(r0);

        local_tuple<tuple_t, TupleLocsT> local_context(local_args, args.locs);
        return local_func_result<
            N, Parent, local_tuple_t>
        ::eval(local_context);
    }

    A0 a0; //  actors
};

namespace impl {

    template <
        int N, int Parent,
        typename T0 = nil_t,