postgres$ createlang plperlu mydb

##</code><code>##

create function palindrome(text) returns boolean 
language plperl 
immutable
as '

  my $arg = shift;
  my ($canonical = lc $arg) =~ s/\s+//g;
  return ($canonical eq reverse $canonical) ? "true" : "false";

';

##</code><code>##

select name, region, country, population
from towns
where palindrome(name);