What really irks me is that the only way to undefine them (locally) is to do something like:

"jeffrey" =~ /(.*?)(.)\2(.*)/;
print "$1 + $2 + $2 + $3 = $1$2$2$3\n";

{
  local ($1,$2,$3);
  print "$1 + $2 + $2 + $3 = $1$2$2$3\n";
  "" =~ /(?=)/;
  print "$1 + $2 + $2 + $3 = $1$2$2$3\n";
}
[download]

The output is:

je + f + f + rey = jeffrey
je + f + f + rey = jeffrey
 +  +  +  =
[download]

Sigh. And you can't do a blanket localization -- that's the worst part; I have to know how many $DIGIT variables are in use, so I know how many to localize. That sucks.

japhy -- Perl and Regex Hacker