croak will say the error was in
process_something's caller if
process_something was called from another package. For example,
use strict;
use warnings;
package Module;
use Carp qw( croak );
my %handler = (
foo => sub { ref $_[0] eq 'ARRAY' or croak "foo key takes a hashref
+"; 1 },
bar => sub { $_[0] =~ /wibble$/ or croak "bar key must end with 'wi
+bble'"; 1 },
);
sub process_something {
my %arg = @_;
my @results;
while( my ( $elem, $param ) = each %arg ) {
push @results, $handler{ $elem }( $param );
}
}
package main;
Module::process_something( foo => 'a' ); # <-- line 27.
outputs
foo key takes a hashref at 554371.pl line 27