/*=============================================================================
    Phoenix V1.0
    Copyright (c) 2001-2002 Joel de Guzman

    Permission to copy, use, modify, sell and distribute this software
    is granted provided this copyright notice appears in all copies.
    This software is provided "as is" without express or implied
    warranty, and with no claim as to its suitability for any purpose.
==============================================================================*/
#ifndef PHOENIX_STATEMENTS_HPP
#define PHOENIX_STATEMENTS_HPP

///////////////////////////////////////////////////////////////////////////////
#include "boost/spirit/phoenix/composite.hpp"

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

///////////////////////////////////////////////////////////////////////////////
//
//  sequential_composite
//
//      Two or more actors separated by the comma generates a
//      sequential_composite which is a composite actor. Example:
//
//          actor,
//          actor,
//          actor
//
//      The actors are evaluated sequentially. The result type of this
//      is void. Note that the last actor should not have a trailing
//      comma.
//
///////////////////////////////////////////////////////////////////////////////
template <typename A0, typename A1>
struct sequential_composite {

    typedef sequential_composite<A0, A1> self_t;

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

    sequential_composite(A0 const& _0, A1 const& _1)
    :   a0(_0), a1(_1) {}

    template <typename TupleT>
    void
    eval(TupleT const& args) const
    {
        a0.eval(args);
        a1.eval(args);
    }

    A0 a0; A1 a1; //  actors
};

//////////////////////////////////
template <typename BaseT0, typename BaseT1>
inline actor<sequential_composite<actor<BaseT0>, actor<BaseT1> > >
operator,(actor<BaseT0> const& _0, actor<BaseT1> const& _1)
{
    return sequential_composite<actor<BaseT0>, actor<BaseT1> >(_0, _1);
}

///////////////////////////////////////////////////////////////////////////////
//
//  if_then_else_composite
//
//      This composite has two (2) forms:
//
//          if_(condition)
//          [
//              statement
//          ]
//
//      and
//
//          if_(condition)
//          [
//              true_statement
//          ]
//          .else_
//          [
//              false_statement
//          ]
//
//      where condition is an actor that evaluates to bool. If condition
//      is true, the true_statement (again an actor) is executed
//      otherwise, the false_statement (another actor) is executed. The
//      result type of this is void. Note the trailing underscore after
//      if_ and the the leading dot and the trailing underscore before
//      and after .else_.
//
///////////////////////////////////////////////////////////////////////////////
template <typename CondT, typename ThenT, typename ElseT>
struct if_then_else_composite {

    typedef if_then_else_composite<CondT, ThenT, ElseT> self_t;

    template <typename TupleT>
    struct result {

        typedef void type;
    };

    if_then_else_composite(
        CondT const& cond_,
        ThenT const& then_,
        ElseT const& else__)
    :   cond(cond_), then(then_), else_(else__) {}

    template <typename TupleT>
    void eval(TupleT const& args) const
    {
        if (cond.eval(args))
            then.eval(args);
        else
            else_.eval(args);
    }

    CondT cond; ThenT then; ElseT else_; //  actors
};

//////////////////////////////////
template <typename CondT, typename ThenT>
struct else_gen {

    else_gen(CondT const& cond_, ThenT const& then_)
    :   cond(cond_), then(then_) {}

    template <typename ElseT>
    actor<if_then_else_composite<CondT, ThenT,
        typename as_actor<ElseT>::type> >
    operator[](ElseT const& else_)
    {
        typedef if_then_else_composite<CondT, ThenT,
            typename as_actor<ElseT>::type>
        result;

        return result(cond, then, as_actor<ElseT>::convert(else_));
    }

    CondT cond; ThenT then;
};

//////////////////////////////////
template <typename CondT, typename ThenT>
struct if_then_composite {

    typedef if_then_composite<CondT, ThenT> self_t;

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

    if_then_composite(CondT const& cond_, ThenT const& then_)
    :   cond(cond_), then(then_), else_(cond, then) {}

    template <typename TupleT>
    void eval(TupleT const& args) const
    {
        if (cond.eval(args))
            then.eval(args);
    }

    CondT cond; ThenT then; //  actors
    else_gen<CondT, ThenT> else_;
};

//////////////////////////////////
template <typename CondT>
struct if_gen {

    if_gen(CondT const& cond_)
    :   cond(cond_) {}

    template <typename ThenT>
    actor<if_then_composite<
        typename as_actor<CondT>::type,
        typename as_actor<ThenT>::type> >
    operator[](ThenT const& then) const
    {
        typedef if_then_composite<
            typename as_actor<CondT>::type,
            typename as_actor<ThenT>::type>
        result;

        return result(
            as_actor<CondT>::convert(cond),
            as_actor<ThenT>::convert(then));
    }

    CondT cond;
};

//////////////////////////////////
template <typename CondT>
inline if_gen<CondT>
if_(CondT const& cond)
{
    return if_gen<CondT>(cond);
}

///////////////////////////////////////////////////////////////////////////////
//
//  while_composite
//
//      This composite has the form:
//
//          while_(condition)
//          [
//              statement
//          ]
//
//      While the condition (an actor) evaluates to true, statement
//      (another actor) is executed. The result type of this is void.
//      Note the trailing underscore after while_.
//
///////////////////////////////////////////////////////////////////////////////
template <typename CondT, typename DoT>
struct while_composite {

    typedef while_composite<CondT, DoT> self_t;

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

    while_composite(CondT const& cond_, DoT const& do__)
    :   cond(cond_), do_(do__) {}

    template <typename TupleT>
    void eval(TupleT const& args) const
    {
        while (cond.eval(args))
            do_.eval(args);
    }

    CondT cond;
    DoT do_;
};

//////////////////////////////////
template <typename CondT>
struct while_gen {

    while_gen(CondT const& cond_)
    :   cond(cond_) {}

    template <typename DoT>
    actor<while_composite<
        typename as_actor<CondT>::type,
        typename as_actor<DoT>::type> >
    operator[](DoT const& do_) const
    {
        typedef while_composite<
            typename as_actor<CondT>::type,
            typename as_actor<DoT>::type>
        result;

        return result(
            as_actor<CondT>::convert(cond),
            as_actor<DoT>::convert(do_));
    }

    CondT cond;
};

//////////////////////////////////
template <typename CondT>
inline while_gen<CondT>
while_(CondT const& cond)
{
    return while_gen<CondT>(cond);
}

///////////////////////////////////////////////////////////////////////////////
//
//  do_composite
//
//      This composite has the form:
//
//          do_
//          [
//              statement
//          ]
//          .while_(condition)
//
//      While the condition (an actor) evaluates to true, statement
//      (another actor) is executed. The statement is executed at least
//      once. The result type of this is void. Note the trailing
//      underscore after do_ and the the leading dot and the trailing
//      underscore before and after .while_.
//
///////////////////////////////////////////////////////////////////////////////
template <typename DoT, typename CondT>
struct do_composite {

    typedef do_composite<DoT, CondT> self_t;

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

    do_composite(DoT const& do__, CondT const& cond_)
    :   do_(do__), cond(cond_) {}

    template <typename TupleT>
    void eval(TupleT const& args) const
    {
        do
            do_.eval(args);
        while (cond.eval(args));
    }

    DoT do_;
    CondT cond;
};

////////////////////////////////////
template <typename DoT>
struct do_gen2 {

    do_gen2(DoT const& do__)
    :   do_(do__) {}

    template <typename CondT>
    actor<do_composite<
        typename as_actor<DoT>::type,
        typename as_actor<CondT>::type> >
    while_(CondT const& cond) const
    {
        typedef do_composite<
            typename as_actor<DoT>::type,
            typename as_actor<CondT>::type>
        result;

        return result(
            as_actor<DoT>::convert(do_),
            as_actor<CondT>::convert(cond));
    }

    DoT do_;
};

////////////////////////////////////
struct do_gen {

    template <typename DoT>
    do_gen2<DoT>
    operator[](DoT const& do_) const
    {
        return do_gen2<DoT>(do_);
    }
};

do_gen const do_ = do_gen();

///////////////////////////////////////////////////////////////////////////////
//
//  for_composite
//
//      This statement has the form:
//
//          for_(init, condition, step)
//          [
//              statement
//          ]
//
//      Where init, condition, step and statement are all actors. init
//      is executed once before entering the for-loop. The for-loop
//      exits once condition evaluates to false. At each loop iteration,
//      step and statement is called. The result of this statement is
//      void. Note the trailing underscore after for_.
//
///////////////////////////////////////////////////////////////////////////////
template <typename InitT, typename CondT, typename StepT, typename DoT>
struct for_composite {

    typedef composite<InitT, CondT, StepT, DoT> self_t;

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

    for_composite(
        InitT const& init_,
        CondT const& cond_,
        StepT const& step_,
        DoT const& do__)
    :   init(init_), cond(cond_), step(step_), do_(do__) {}

    template <typename TupleT>
    void
    eval(TupleT const& args) const
    {
        for (init.eval(args); cond.eval(args); step.eval(args))
            do_.eval(args);
    }

    InitT init; CondT cond; StepT step; DoT do_; //  actors
};

//////////////////////////////////
template <typename InitT, typename CondT, typename StepT>
struct for_gen {

    for_gen(
        InitT const& init_,
        CondT const& cond_,
        StepT const& step_)
    :   init(init_), cond(cond_), step(step_) {}

    template <typename DoT>
    actor<for_composite<
        typename as_actor<InitT>::type,
        typename as_actor<CondT>::type,
        typename as_actor<StepT>::type,
        typename as_actor<DoT>::type> >
    operator[](DoT const& do_) const
    {
        typedef for_composite<
            typename as_actor<InitT>::type,
            typename as_actor<CondT>::type,
            typename as_actor<StepT>::type,
            typename as_actor<DoT>::type>
        result;

        return result(
            as_actor<InitT>::convert(init),
            as_actor<CondT>::convert(cond),
            as_actor<StepT>::convert(step),
            as_actor<DoT>::convert(do_));
    }

    InitT init; CondT cond; StepT step;
};

//////////////////////////////////
template <typename InitT, typename CondT, typename StepT>
inline for_gen<InitT, CondT, StepT>
for_(InitT const& init, CondT const& cond, StepT const& step)
{
    return for_gen<InitT, CondT, StepT>(init, cond, step);
}

}   //  namespace phoenix

#endif
