in reply to OOP - Constant Vs. Subroutine

The constant pragma creates a sub with a specific prototype, allowing it to be in-lined. For some uses in OO code, you're probably better off using class methods, since subclasses can override them.

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Re^2: OOP - Constant Vs. Subroutine
by 2xlp (Sexton) on May 11, 2007 at 21:46 UTC
    subclasses can override constants too.
[reply]
      How would you do that? Would you have to call it like a method? 
      Class->constant;

      [download]
      That would prevent the in-lining behavior, but I guess it's no worse than a normally defined simple method.
[reply]
[d/l]

        Not really, Class->constant won't inherit from Superclass->constant ; it needs to be defined in both.

        however $classObject->constant will inherit constants from superclass as class object methods , and allow the ability to override

        so... 

        package aaa;
use constant HELLO=> 'world';
use constant PUNCTUATION=> '!';
sub new { #std constructor here }

package bbb;
our @ISA= qw( aaa );
use constant HELLO=> 'universe';

package main;
my $a= aaa->new();
my $b= bbb->new();

print "\n Hello " . $a->HELLO . $a->PUNCTUATION ;
print "\n Hello " . $b->HELLO . $b->PUNCTUATION ;

        [download]

        will get you 

        Hello world!
Hello universe!

        [download]

        but bbb->PUNCTUATION doesn't exist

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[d/l]
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