# bart's setup:
$re = 'Il est (\d+) heurs moins (\d+).';
$translation = 'It\'s $2 to $1.';
$_ = 'Il est 14 heurs moins 28.';

# my code:
$translator{$re} ||= do {
  (my $t = $translation) =~ s/([\\"])/\\$1/g;
  eval qq(sub { "$t" });
};
s/$re/$translator{$re}()/e;

# and a print:
print