// Copyright Alexander Nasonov 2005
//
// Distributed under 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)
// 
// Acknowledge: Maxim Yegorushkin for the idea of in-place guard.

#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/punctuation/comma.hpp>
#include <boost/preprocessor/seq/enum.hpp>
#include <boost/preprocessor/seq/for_each.hpp>

extern void* _finally_last_params; // TODO: boost::thread_specific_ptr<void>

// Generate _finally_typeof_{__LINE__}{var}
#define FINALLY_AUX_TYPE(var) \
    BOOST_PP_CAT(_finally_typeof_, BOOST_PP_CAT(__LINE__,var))

#define FINALLY_AUX_DEREF(r,params,var) params -> var ,

#define FINALLY_AUX_TYPEDEF(r,_,var) typedef typeof(var) FINALLY_AUX_TYPE(var);

#define FINALLY_AUX_SEMICOLON() ;
#define FINALLY_AUX_REF(r,end,var) FINALLY_AUX_TYPE(var) & var end()

#define FINALLY_BEGIN(seq)                                                   \
    BOOST_PP_SEQ_FOR_EACH(FINALLY_AUX_TYPEDEF,_,seq)                         \
    struct BOOST_PP_CAT(_finally_params_,__LINE__) {                         \
        BOOST_PP_SEQ_FOR_EACH(FINALLY_AUX_REF,FINALLY_AUX_SEMICOLON,seq)     \
    } BOOST_PP_CAT(_finally_params_,__LINE__) = { BOOST_PP_SEQ_ENUM(seq) };  \
    _finally_last_params = &BOOST_PP_CAT(_finally_params_,__LINE__);         \
    struct BOOST_PP_CAT(_finally_guard_,__LINE__) {                          \
        void* _finally_params;                                               \
        BOOST_PP_CAT(~_finally_guard_,__LINE__)() {                          \
            typedef struct BOOST_PP_CAT(_finally_params_,__LINE__) params;   \
            params* p= static_cast<params*>(_finally_params);                \
            _finally_body(BOOST_PP_SEQ_FOR_EACH(FINALLY_AUX_DEREF,p,seq) 0); \
        }                                                                    \
        static void _finally_body(                                           \
            BOOST_PP_SEQ_FOR_EACH(FINALLY_AUX_REF,BOOST_PP_COMMA,seq) int)

#define FINALLY_END } BOOST_PP_CAT(_finally_guard_,__LINE__) = { _finally_last_params };

#include <iostream>
#include <boost/preprocessor/seq/seq.hpp>

void* _finally_last_params = 0;

int main()
{
    int i = 2, j = 1;

    FINALLY_BEGIN((i)(j)) throw()
    {
        std::cerr << i+j << '\n';
    } FINALLY_END

    FINALLY_BEGIN((i)(j)) try
    {
        std::cerr << i-j << '\n';
    } catch(...) {} FINALLY_END
}