Re: Carp::Clan

[diotalevi]

I don't get it. Can you demonstrate the problem that this solves?

[Aristotle]

my %handler; BEGIN { %handler = (
    foo => sub { ref $_[0] eq 'ARRAY' or croak "foo key takes a hashre
+f"; ... },
    bar => sub { $_[0] =~ /wibble$/ or croak "bar key must end with 'w
+ibble'"; ... },
) }

sub process_something {
    my %arg = @_;
    my @results;

    while( my ( $elem, $param ) = each %arg ) {
        push @results, $handler->{ $elem }->( $param );
    }
}

croak will say the error was in process_something, when you really want it to be thrown for the where the call to process_something was.

[ikegami]

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