casts.hpp

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

    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)
==============================================================================*/

#ifndef PHOENIX_CASTS_HPP
#define PHOENIX_CASTS_HPP

///////////////////////////////////////////////////////////////////////////////
#include <boost/spirit/phoenix/actor.hpp>
#include <boost/spirit/phoenix/composite.hpp>
#include <boost/static_assert.hpp>

///////////////////////////////////////////////////////////////////////////////
namespace phoenix {

///////////////////////////////////////////////////////////////////////////////
//
//  Phoenix predefined maximum construct_ limit. This limit defines the maximum
//  number of parameters supported for calles to the set of construct_ template
//  functions (lazy object construction, see below). This number defaults to 3.
//  The actual maximum is rounded up in multiples of 3. Thus, if this value
//  is 4, the actual limit is 6. The ultimate maximum limit in this
//  implementation is 15.
//  PHOENIX_CONSTRUCT_LIMIT should NOT be greater than PHOENIX_LIMIT!

#if !defined(PHOENIX_CONSTRUCT_LIMIT)
#define PHOENIX_CONSTRUCT_LIMIT PHOENIX_LIMIT
#endif

// ensure PHOENIX_CONSTRUCT_LIMIT <= PHOENIX_LIMIT
BOOST_STATIC_ASSERT(PHOENIX_CONSTRUCT_LIMIT <= PHOENIX_LIMIT);

// ensure PHOENIX_CONSTRUCT_LIMIT <= 15
BOOST_STATIC_ASSERT(PHOENIX_CONSTRUCT_LIMIT <= 15);

///////////////////////////////////////////////////////////////////////////////
//
//  Lazy C++ casts
//
//      The set of lazy C++ cast template classes and functions provide a way
//      of lazily casting certain type to another during parsing.
//      The lazy C++ templates are (syntactically) used very much like
//      the well known C++ casts:
//
//          A *a = static_cast_<A *>(...actor returning a convertible type...);
//
//      where the given parameter should be an actor, which eval() function
//      returns a convertible type.
//
///////////////////////////////////////////////////////////////////////////////
template <typename T, typename A>
struct static_cast_l {

    template <typename TupleT>
    struct result { typedef T type; };

    static_cast_l(A const& a_)
    :   a(a_) {}

    template <typename TupleT>
    T
    eval(TupleT const& args) const
    {
        return static_cast<T>(a.eval(args));
    }

    A a;
};

//////////////////////////////////
template <typename T, typename BaseAT>
inline actor<static_cast_l<T, BaseAT> >
static_cast_(actor<BaseAT> const& a)
{
    typedef static_cast_l<T, BaseAT> cast_t;
    return actor<cast_t>(cast_t(a));
}

//////////////////////////////////
template <typename T, typename A>
struct dynamic_cast_l {

    template <typename TupleT>
    struct result { typedef T type; };

    dynamic_cast_l(A const& a_)
    :   a(a_) {}

    template <typename TupleT>
    T
    eval(TupleT const& args) const
    {
        return dynamic_cast<T>(a.eval(args));
    }

    A a;
};

//////////////////////////////////
template <typename T, typename BaseAT>
inline actor<dynamic_cast_l<T, BaseAT> >
dynamic_cast_(actor<BaseAT> const& a)
{
    typedef dynamic_cast_l<T, BaseAT> cast_t;
    return actor<cast_t>(cast_t(a));
}

//////////////////////////////////
template <typename T, typename A>
struct reinterpret_cast_l {

    template <typename TupleT>
    struct result { typedef T type; };

    reinterpret_cast_l(A const& a_)
    :   a(a_) {}

    template <typename TupleT>
    T
    eval(TupleT const& args) const
    {
        return reinterpret_cast<T>(a.eval(args));
    }

    A a;
};

//////////////////////////////////
template <typename T, typename BaseAT>
inline actor<reinterpret_cast_l<T, BaseAT> >
reinterpret_cast_(actor<BaseAT> const& a)
{
    typedef reinterpret_cast_l<T, BaseAT> cast_t;
    return actor<cast_t>(cast_t(a));
}

//////////////////////////////////
template <typename T, typename A>
struct const_cast_l {

    template <typename TupleT>
    struct result { typedef T type; };

    const_cast_l(A const& a_)
    :   a(a_) {}

    template <typename TupleT>
    T
    eval(TupleT const& args) const
    {
        return const_cast<T>(a.eval(args));
    }

    A a;
};

//////////////////////////////////
template <typename T, typename BaseAT>
inline actor<const_cast_l<T, BaseAT> >
const_cast_(actor<BaseAT> const& a)
{
    typedef const_cast_l<T, BaseAT> cast_t;
    return actor<cast_t>(cast_t(a));
}

///////////////////////////////////////////////////////////////////////////////
//
//  construct_
//
//      Lazy object construction
//
//      The set of construct_<> template classes and functions provide a way
//      of lazily constructing certain object from a arbitrary set of
//      actors during parsing.
//      The construct_ templates are (syntactically) used very much like
//      the well known C++ casts:
//
//          A a = construct_<A>(...arbitrary list of actors...);
//
//      where the given parameters are submitted as parameters to the
//      contructor of the object of type A. (This certainly implies, that
//      type A has a constructor with a fitting set of parameter types
//      defined.)
//
//      The maximum number of needed parameters is controlled through the
//      preprocessor constant PHOENIX_CONSTRUCT_LIMIT. Note though, that this
//      limit should not be greater than PHOENIX_LIMIT.
//
///////////////////////////////////////////////////////////////////////////////
template <typename T>
struct construct_l_0 {
    typedef T result_type;

    T operator()() const {
        return T();
    }
};


template <typename T>
struct construct_l {

    template <
            typename A
        ,   typename B
        ,   typename C

#if PHOENIX_CONSTRUCT_LIMIT > 3
        ,   typename D
        ,   typename E
        ,   typename F

#if PHOENIX_CONSTRUCT_LIMIT > 6
        ,   typename G
        ,   typename H
        ,   typename I

#if PHOENIX_CONSTRUCT_LIMIT > 9
        ,   typename J
        ,   typename K
        ,   typename L

#if PHOENIX_CONSTRUCT_LIMIT > 12
        ,   typename M
        ,   typename N
        ,   typename O
#endif
#endif
#endif
#endif
    >
    struct result { typedef T type; };

    T operator()() const 
    {
        return T();
    }

    template <typename A>
    T operator()(A const& a) const 
    {
        T t(a); 
        return t;
    }

    template <typename A, typename B>
    T operator()(A const& a, B const& b) const 
    {
        T t(a, b);
        return t;
    }

    template <typename A, typename B, typename C>
    T operator()(A const& a, B const& b, C const& c) const 
    {
        T t(a, b, c);
        return t;
    }

#if PHOENIX_CONSTRUCT_LIMIT > 3
    template <
        typename A, typename B, typename C, typename D
    >
    T operator()(
        A const& a, B const& b, C const& c, D const& d) const
    {
        T t(a, b, c, d);
        return t;
    }

    template <
        typename A, typename B, typename C, typename D, typename E
    >
    T operator()(
        A const& a, B const& b, C const& c, D const& d, E const& e) const
    {
        T t(a, b, c, d, e);
        return t;
    }

    template <
        typename A, typename B, typename C, typename D, typename E,
        typename F
    >
    T operator()(
        A const& a, B const& b, C const& c, D const& d, E const& e,
        F const& f) const
    {
        T t(a, b, c, d, e, f);
        return t;
    }

#if PHOENIX_CONSTRUCT_LIMIT > 6
    template <
        typename A, typename B, typename C, typename D, typename E,
        typename F, typename G
    >
    T operator()(
        A const& a, B const& b, C const& c, D const& d, E const& e,
        F const& f, G const& g) const
    {
        T t(a, b, c, d, e, f, g);
        return t;
    }

    template <
        typename A, typename B, typename C, typename D, typename E,
        typename F, typename G, typename H
    >
    T operator()(
        A const& a, B const& b, C const& c, D const& d, E const& e,
        F const& f, G const& g, H const& h) const
    {
        T t(a, b, c, d, e, f, g, h);
        return t;
    }

    template <
        typename A, typename B, typename C, typename D, typename E,
        typename F, typename G, typename H, typename I
    >
    T operator()(
        A const& a, B const& b, C const& c, D const& d, E const& e,
        F const& f, G const& g, H const& h, I const& i) const
    {
        T t(a, b, c, d, e, f, g, h, i);
        return t;
    }

#if PHOENIX_CONSTRUCT_LIMIT > 9
    template <
        typename A, typename B, typename C, typename D, typename E,
        typename F, typename G, typename H, typename I, typename J
    >
    T operator()(
        A const& a, B const& b, C const& c, D const& d, E const& e,
        F const& f, G const& g, H const& h, I const& i, J const& j) const
    {
        T t(a, b, c, d, e, f, g, h, i, j);
        return t;
    }

    template <
        typename A, typename B, typename C, typename D, typename E,
        typename F, typename G, typename H, typename I, typename J,
        typename K
    >
    T operator()(
        A const& a, B const& b, C const& c, D const& d, E const& e,
        F const& f, G const& g, H const& h, I const& i, J const& j,
        K const& k) const
    {
        T t(a, b, c, d, e, f, g, h, i, j, k);
        return t;
    }

    template <
        typename A, typename B, typename C, typename D, typename E,
        typename F, typename G, typename H, typename I, typename J,
        typename K, typename L
    >
    T operator()(
        A const& a, B const& b, C const& c, D const& d, E const& e,
        F const& f, G const& g, H const& h, I const& i, J const& j,
        K const& k, L const& l) const
    {
        T t(a, b, c, d, e, f, g, h, i, j, k, l);
        return t;
    }

#if PHOENIX_CONSTRUCT_LIMIT > 12
    template <
        typename A, typename B, typename C, typename D, typename E,
        typename F, typename G, typename H, typename I, typename J,
        typename K, typename L, typename M
    >
    T operator()(
        A const& a, B const& b, C const& c, D const& d, E const& e,
        F const& f, G const& g, H const& h, I const& i, J const& j,
        K const& k, L const& l, M const& m) const
    {
        T t(a, b, c, d, e, f, g, h, i, j, k, l, m);
        return t;
    }

    template <
        typename A, typename B, typename C, typename D, typename E,
        typename F, typename G, typename H, typename I, typename J,
        typename K, typename L, typename M, typename N
    >
    T operator()(
        A const& a, B const& b, C const& c, D const& d, E const& e,
        F const& f, G const& g, H const& h, I const& i, J const& j,
        K const& k, L const& l, M const& m, N const& n) const
    {
        T t(a, b, c, d, e, f, g, h, i, j, k, l, m, n);
        return t;
    }

    template <
        typename A, typename B, typename C, typename D, typename E,
        typename F, typename G, typename H, typename I, typename J,
        typename K, typename L, typename M, typename N, typename O
    >
    T operator()(
        A const& a, B const& b, C const& c, D const& d, E const& e,
        F const& f, G const& g, H const& h, I const& i, J const& j,
        K const& k, L const& l, M const& m, N const& n, O const& o) const
    {
        T t(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o);
        return t;
    }

#endif
#endif
#endif
#endif
};


template <typename T>
struct construct_1 {

    template <
            typename A
    >
    struct result { typedef T type; };

    template <typename A>
    T operator()(A const& a) const 
    {
        T t(a);
        return t;
    }

};

template <typename T>
struct construct_2 {

    template <
            typename A
        ,   typename B
    >
    struct result { typedef T type; };

    template <typename A, typename B>
    T operator()(A const& a, B const& b) const 
    {
        T t(a, b);
        return t;
    }

};

template <typename T>
struct construct_3 {

    template <
            typename A
        ,   typename B
        ,   typename C
    >
    struct result { typedef T type; };

    template <typename A, typename B, typename C>
    T operator()(A const& a, B const& b, C const& c) const 
    {
        T t(a, b, c);
        return t;
    }
};

#if PHOENIX_CONSTRUCT_LIMIT > 3
template <typename T>
struct construct_4 {

    template <
            typename A
        ,   typename B
        ,   typename C
        ,   typename D
    >
    struct result { typedef T type; };