fullwidth digit <-> ascii digit

#!/usr/bin/perl
use strict;
use warnings;
use utf8;
use open qw(:std :encoding(utf8));
sub num_zen($);
sub zen_num($);
sub num_zen($) {
  my $s = shift;
  my $zen = [ split '', q(０１２３４５６７８９) ];
  $s =~ s/(?<![0-9])(?![0-9]{2}(?:\D|\b))[0-9]+/
      join '', map { $$zen[$_] } split '', $&
    /egx;
  return $s;
}
sub zen_num($) {
  my $s = shift;
  my $zen = [ split //, q(０１２３４５６７８９) ];
  my $tab = { map { $$zen[$_], $_ } 0 .. 9 };
  $s =~ s/(?<![０−９])[０-９]+/
      join '', map { $$tab{$_} } split '', $&
    /egx;
  return $s;
}
my $p = tell DATA;
while (<DATA>) {
  print num_zen $_;
}
seek DATA, $p, 0;
while (<DATA>) {
  print zen_num $_;
}
seek DATA, $p, 0;
while (<DATA>) {
  print num_zen zen_num $_;
}
__DATA__
1 11 111 1111 １ １１ １１１ １１１１
a0a a00a a000a あ０あ あ００あ あ０００あ
00 0０ ０0 ００
000 00０ 0０0 0００ ０00 ０0０ ００0 ０００