Re: C-g while exiting the minibuffer

[Stefan Monnier]

Found it:

    revno: 39564
    committer: Gerd Moellmann <address@hidden>
    timestamp: Fri 2001-10-05 09:48:47 +0000
    message:
      (LIST_END_P, FOREACH): New macros.


   /* Loop over Lisp list LIST.  Signal an error if LIST is not a proper
      list, or if it contains circles.
      
      HARE and TORTOISE should be the names of Lisp_Object variables, and
      N should be the name of an EMACS_INT variable declared in the
      function where the macro is used.  Each nested loop should use
      its own variables.
   
      In the loop body, HARE is set to each cons of LIST, and N is the
      length of the list processed so far.  */
   
   #define LIST_END_P(list, obj)                                \
     (NILP (obj)                                                \
      ? 1                                                       \
      : (CONSP (obj)                                    \
         ? 0                                            \
         : (wrong_type_argument (Qlistp, (list), 0)), 1))
   
   #define FOREACH(hare, list, tortoise, n)             \
     for (tortoise = hare = (list), n = 0;                      \
          !LIST_END_P (list, hare);                     \
          (hare = XCDR (hare), ++n,                     \
        ((n & 1) != 0                                   \
         ? (tortoise = XCDR (tortoise),                 \
            (EQ (hare, tortoise)                        \
             && (circular_list_error ((list)), 1)))     \
         : 0)))

Died in 2011:

    revno: 103880.1.17
    committer: Paul Eggert <address@hidden>
    branch nick: atest
    timestamp: Mon 2011-04-11 22:17:33 -0700
    message:
      * lisp.h (circular_list_error, FOREACH): Remove; unused.


-- Stefan