chomp($l) or &$bad_data('missing end-of-line');
$l !~ m/\P{IsPrint}/ or &$bad_data('nonprinting char(s)');
- $l !~ m/\\/ or &$bad_data('data contains backslashes');
my @v= split /\t/, $l, -1;
@v==6 or &$bad_data('wrong number of fields');
my ($commod,$stall) = @v;