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// file : Utility/Hetero/Shell.hpp
// author : Boris Kolpackov <boris@kolpackov.net>
// copyright : Copyright (c) 2002-2003 Boris Kolpackov
// license : http://kolpackov.net/license.html
#ifndef UTILITY_HETERO_SHELL_HPP
#define UTILITY_HETERO_SHELL_HPP
namespace Utility
{
namespace Hetero
{
//
//
//
class ShellCore
{
protected:
template <typename F, typename T0>
static typename F::RetType
apply (F& f, TypedContainer<TypeList<T0> >& c)
{
if (type_check <T0> (c)) return type_apply<T0> (f, c);
throw Utility::Hetero::Typing ();
}
template <typename F, typename T0, typename T1>
static typename F::RetType
apply (F& f, TypedContainer<TypeList<T0, T1> >& c)
{
if (type_check <T0> (c)) return type_apply<T0> (f, c);
if (type_check <T1> (c)) return type_apply<T1> (f, c);
throw Utility::Hetero::Typing ();
}
template <typename F, typename T0, typename T1, typename T2>
static typename F::RetType
apply (F& f, TypedContainer<TypeList<T0, T1, T2> >& c)
{
if (type_check <T0> (c)) return type_apply<T0> (f, c);
if (type_check <T1> (c)) return type_apply<T1> (f, c);
if (type_check <T2> (c)) return type_apply<T2> (f, c);
throw Utility::Hetero::Typing ();
}
private:
template <typename T>
static bool
type_check (Container& c)
{
return c.type () == typeid (T);
}
template <typename T, typename F>
static typename F::RetType
type_apply (F& f, Container& c)
{
return f (c. template value<T> ());
}
};
//
//
//
template <typename F>
struct Shell : F, ShellCore
{
using F::operator ();
template <typename T>
typename F::RetType
operator () (TypedContainer<T>& p)
{
return apply (*this, p);
}
};
}
}
#endif // UTILITY_HETERO_SHELL_HPP
//$Id$
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