http://qs321.pair.com?node_id=603091


in reply to Re: Inheritance and calling a subclass method *from* a baseclass method...
in thread Inheritance and calling a subclass method *from* a baseclass method...

I would use Carp::confess in this case. And I probably wouldn't check if the method was overloaded on new(). Please consider the following example: 

package MyPackage;

use strict;
use warnings;

use Carp qw(confess);

sub new {
    my ($class) = @_;
    my $self = {};
    bless $self, $class;
    return $self;
}

sub abstract_method {
    my ($self) = @_;

    my ($method) = ( caller(0) )[3];
    confess "${method} should be overloaded.";
}

package main;

my $p = MyPackage->new();
$p->abstract_method();

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Don't you think it is cleaner?

Igor 'izut' Sutton
your code, your rules.

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Re^3: Inheritance and calling a subclass method *from* a baseclass method... (error data)
by tye (Sage) on Mar 04, 2007 at 03:42 UTC

    I think the two primary pieces of information I would want in a "method should be overloaded" error message are the name of the method and the name of the class that didn't implement it. So I really think you need to report the latter (my $class= ref $self || $self;).

    I'm not sure why you are writing code to look up the string "abstract_method" (perhaps so you can re-use this subroutine similar to *replace_me= \&abstrace_method;? -- no, doing so would still report "abstract_method" according to my testing, unfortunately). And, at least in this case, you don't even need to include the method name in the text since Carp::confess will already show that in the stack trace (though the error message is clearer if you do, of course). :)

    - tye        

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      Actually the abstract_method name was used as example. Maybe was better if I used your_abstract_method_here or something.

      Igor 'izut' Sutton
      your code, your rules.

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        I wasn't particularly confused on that point and another choice of example name wouldn't have eliminated my question: Why would you choose to write: 

        sub whatever {
    #...
    my ($method) = ( caller(0) )[3];
    #...
}

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        when it appears to be functionally equivalent to the trival and thus clearer: 

        sub whatever {
    #...
    my $method= "whatever";
    #...
}

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        - tye        

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