map.h

/*
 * Created by William Swanson in 2012.
 *
 * I, William Swanson, dedicate this work to the public domain.
 * I waive all rights to the work worldwide under copyright law,
 * including all related and neighboring rights,
 * to the extent allowed by law.
 *
 * You can copy, modify, distribute and perform the work,
 * even for commercial purposes, all without asking permission.
 */

#ifndef MAP_H_INCLUDED
#define MAP_H_INCLUDED

#define EVAL0(...) __VA_ARGS__
#define EVAL1(...) EVAL0(EVAL0(EVAL0(__VA_ARGS__)))
#define EVAL2(...) EVAL1(EVAL1(EVAL1(__VA_ARGS__)))
#define EVAL3(...) EVAL2(EVAL2(EVAL2(__VA_ARGS__)))
#define EVAL4(...) EVAL3(EVAL3(EVAL3(__VA_ARGS__)))
#define EVAL(...)  EVAL4(EVAL4(EVAL4(__VA_ARGS__)))

#define MAP_END(...)
#define MAP_OUT
#define MAP_COMMA ,

#define MAP_GET_END2() 0, MAP_END
#define MAP_GET_END1(...) MAP_GET_END2
#define MAP_GET_END(...) MAP_GET_END1
#define MAP_NEXT0(test, next, ...) next MAP_OUT
#define MAP_NEXT1(test, next) MAP_NEXT0(test, next, 0)
#define MAP_NEXT(test, next)  MAP_NEXT1(MAP_GET_END test, next)

#define MAP0(f, x, peek, ...) f(x) MAP_NEXT(peek, MAP1)(f, peek, __VA_ARGS__)
#define MAP1(f, x, peek, ...) f(x) MAP_NEXT(peek, MAP0)(f, peek, __VA_ARGS__)

#define MAP_LIST_NEXT1(test, next) MAP_NEXT0(test, MAP_COMMA next, 0)
#define MAP_LIST_NEXT(test, next)  MAP_LIST_NEXT1(MAP_GET_END test, next)

#define MAP_LIST0(f, x, peek, ...) f(x) MAP_LIST_NEXT(peek, MAP_LIST1)(f, peek, __VA_ARGS__)
#define MAP_LIST1(f, x, peek, ...) f(x) MAP_LIST_NEXT(peek, MAP_LIST0)(f, peek, __VA_ARGS__)

/**
 * Applies the function macro `f` to each of the remaining parameters.
 */
#define MAP(f, ...) EVAL(MAP1(f, __VA_ARGS__, ()()(), ()()(), ()()(), 0))

/**
 * Applies the function macro `f` to each of the remaining parameters and
 * inserts commas between the results.
 */
#define MAP_LIST(f, ...) EVAL(MAP_LIST1(f, __VA_ARGS__, ()()(), ()()(), ()()(), 0))

#endif