# suppose %product_id has the "PSLA0L00U00E"-like strings from the DB
# as hash keys, and something useful (row_ids?) as hash values...

open( REJ, ">", "merchant_data.to_review" ) or die $!;

while (<DATA>) {  # reading merchant stuff line-by-line
    my $orig = $_;
    s/\W+//g;
    for my $model ( keys %product_id ) {
        if ( index( $_, $model ) >=0 ) {
            handle_a_match( $orig, $model );
            $orig = '';
            last;
        }

# if the last character of $model is "optional", then
# use this else block:
        else {
            chop ( my $modl = $model );
            if ( index( $_, $modl ) >= 0 ) {
                hanle_a_match( $orig, $model );
                $orig = '';
                last;
            }
        }
    }
    print REJ $orig unless ( $orig eq '' );
}

##</code><code>##

        else {
            my $modelrgx = $model . "?"; # make last character "optional"
            $modelrgx =~ s/[1Il]/[1Il]/g;
            $modelrgx =~ s/[0O]/[0O]/g;
            if ( /$modelrgx/ ) {
                handle_a_match( $orig, $model );
                $orig = '';
                last;
            }
        }