--
-- Perl Weekly Challenge 331
-- Task 2
-- See <https://perlweeklychallenge.org/blog/perl-weekly-challenge-331>
--

CREATE SCHEMA IF NOT EXISTS pwc331;

CREATE OR REPLACE FUNCTION
pwc331.task2_plperl( text, text )
RETURNS boolean
AS $CODE$

   my ( $left, $right ) = @_;

   return 1 if ( lc( $left ) eq lc( $right ) );
   return 0 if ( length( $left ) != length( $right ) );

   my $index = 0;
   my @l = split //, $left;
   my @r = split //, $right;

   my @diff =
       grep { $_->[ 0 ] ne $_->[ 1 ] }
       map { [ $l[ $index ], $r[ $index++ ] ] }
       ( 0 .. $#l );

   return $#diff < 2 ? 1 : 0;

   
$CODE$
LANGUAGE plperl;