Short: modified regexp()
From: Dave Setty <garpoz@locallink.net>
Date: Thu, 10 Dec 1998 02:03:04 -0500
Type: Feature
State: Unclassified

5) A change to regexp() to let it take a single string as argument,
   returning either status, or the string if matched or 0 if not.
   This will make it more useful with map_ and filter_ array, etc.
   Since there's now a cache for compiled regexp patterns, this should
   work fairly efficiently now.

Matthew Julius explains:

varargs string *regexp(string *, string, int)
  Allow an optional third argument to return non matching strings, or return
  an array of 1's and 0's, with 1's representing matching strings in the
  array.
  For examples,
    string *arr;
    arr = ({ "abc", "def", "abbot", "lab" });
    regexp(arr, "ab.") returns ({ "abc", "abbot" })
    regexp(arr, "ab.", 1) returns ({ "def", "lab" })
    regexp(arr, "ab.", 2) returns ({ 1, 0, 1, 0 })