boost/spirit/phoenix/statements.hpp
/*=============================================================================
Phoenix V1.2.1
Copyright (c) 2001-2002 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)
==============================================================================*/
#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
