In <stdlib.h>

#define repeat(INT) for(int i{ 0 }; i < INT; ++i)

#define rep() while(true)

#define until(BOOL) while(!(BOOL))

#define rep_until(BOOL, todo)   \

{                                                   \

    ##todo                                              \

                                                             \

    while (BOOL) {                                \

       ##todo                                \

    }                                                       \

};