/* This may look like nonsense, but it really is -*- mode: C -*-              */
/*                                                                            */
/* Except for parts copied from previous work and as explicitly stated below, */
/* the authors and copyright holders for this work are as follows:            */
/* (C) copyright  2010-2013 Jens Gustedt, INRIA, France                       */
/* (C) copyright  2013 Pierre-Nicolas Clauss                                  */
/* (C) copyright  2012 William Morris                                         */
/*                                                                            */
/* This file is free software; it is part of the P99 project.                 */
/* You can redistribute it and/or modify it under the terms of the QPL as     */
/* given in the file LICENSE. It is distributed without any warranty;         */
/* without even the implied warranty of merchantability or fitness for a      */
/* particular purpose.                                                        */
/*                                                                            */
#pragma once

#define P99_MAX_NUMBER 16
#define P00_ARG(                            \
    _01, _02, _03, _04, _05, _06, _07, _08, \
    _09, _10, _11, _12, _13, _14, _15, _16, \
    _00, ...) _00
#define P00_NARG(...) P00_ARG(__VA_ARGS__,  \
    16, 15, 14, 13, 12, 11, 10,  9,         \
     8,  7,  6,  5,  4,  3,  2,  1,         \
     0, )
#define P99_HAS_COMMA(...) P00_ARG(__VA_ARGS__, \
    1, 1, 1, 1, 1, 1, 1, 1,                     \
    1, 1, 1, 1, 1, 1, 1, 0,                     \
    0)

#define P99_IF_EMPTY(...) P99_IF_EQ(1, P99_IS_EMPTY(__VA_ARGS__))
    // P99_HAS_COMMA(__VA_ARGS__),                         : test if there is just one argument, that might be empty
    // P99_HAS_COMMA(P00_IS__EQ__ __VA_ARGS__),            : test if P99_IS__EQ__ together with the argument adds a comma
    // P99_HAS_COMMA(__VA_ARGS__ (/*empty*/)),             : test if the argument together with a parenthesis adds a comma
    // P99_HAS_COMMA(P00_IS__EQ__ __VA_ARGS__ (/*empty*/)) : test if placing it between P99_IS__EQ__ and the parenthesis adds a comma
    #define P99_IS_EMPTY(...)                                                               \
        P00_ISEMPTY(                                                                        \
            P99_HAS_COMMA(__VA_ARGS__),                                                     \
            P99_HAS_COMMA(P00_IS__EQ__ __VA_ARGS__),                                        \
            P99_HAS_COMMA(__VA_ARGS__ (/*empty*/)),                                         \
            P99_HAS_COMMA(P00_IS__EQ__ __VA_ARGS__ (/*empty*/))                             \
        )
        #define P00_IS__EQ__(...) ,
        #define P00_ISEMPTY(_1, _2, _3, _4) P99_HAS_COMMA(P99_PASTE5(P00_IS_EMPTY_CASE_, _1, _2, _3, _4))
            #define P00_IS_EMPTY_CASE_0000 P00_IS_EMPTY_CASE_0000
            #define P00_IS_EMPTY_CASE_0001 ,
            #define P00_IS_EMPTY_CASE_0010 P00_IS_EMPTY_CASE_0010
            #define P00_IS_EMPTY_CASE_0011 P00_IS_EMPTY_CASE_0011
            #define P00_IS_EMPTY_CASE_0100 P00_IS_EMPTY_CASE_0100
            #define P00_IS_EMPTY_CASE_0101 P00_IS_EMPTY_CASE_0101
            #define P00_IS_EMPTY_CASE_0110 P00_IS_EMPTY_CASE_0110
            #define P00_IS_EMPTY_CASE_0111 P00_IS_EMPTY_CASE_0111
            #define P00_IS_EMPTY_CASE_1000 P00_IS_EMPTY_CASE_1000
            #define P00_IS_EMPTY_CASE_1001 P00_IS_EMPTY_CASE_1001
            #define P00_IS_EMPTY_CASE_1010 P00_IS_EMPTY_CASE_1010
            #define P00_IS_EMPTY_CASE_1011 P00_IS_EMPTY_CASE_1011
            #define P00_IS_EMPTY_CASE_1100 P00_IS_EMPTY_CASE_1100
            #define P00_IS_EMPTY_CASE_1101 P00_IS_EMPTY_CASE_1101
            #define P00_IS_EMPTY_CASE_1110 P00_IS_EMPTY_CASE_1110
            #define P00_IS_EMPTY_CASE_1111 P00_IS_EMPTY_CASE_1111


#define P00_IF_CLAUSE(EXP) P00__IF_CLAUSE(EXP, P00_CLAUSE1, P00_CLAUSE2, ~)
    #define P00__IF_CLAUSE(A, B, C, ...) C
    #define P00_CLAUSE1(...) __VA_ARGS__ P00_IGNORE
        #define P00_IGNORE(...)
    #define P00_CLAUSE2(...) P00_IDENT
        #define P00_IDENT(...) __VA_ARGS__


#define P99_IF_EQ(A, B) P00_IF_CLAUSE(P99_PASTE4(P00_IS_, A, _EQ_, B)())
    #define P00_IS_0_EQ_0(...) ,
    #define P00_IS_1_EQ_1(...) ,


#define P99_CAT2(_1, _2) _1 ## _2
#define P99_PASTE2(_1, _2) \
    P99_CAT2(_1, _2)
#define P99_PASTE3(_1, _2, _3) \
    P99_PASTE2(P99_PASTE2(_1, _2), _3)
#define P99_PASTE4(_1, _2, _3, _4) \
    P99_PASTE2(P99_PASTE3(_1, _2, _3), _4)
#define P99_PASTE5(_1, _2, _3, _4, _5) \
    P99_PASTE2(P99_PASTE4(_1, _2, _3, _4), _5)