SPUG: Constants

[Matt Tucker]

-- Andrew Sweger <andy at n2h2.com> spake thusly:

> On Jul 10, 2000 @ 3:37pm, Jonathan Gardner wrote:
>
>> perl constant pragma (or is it a module? I am not sure...) works but
>> it is clunky to use. You can't use those constants as regular
>> variables, unless you jimmy them around.
>
> Perl's 'use constant pragma (which is a module) uses named
> subroutines as the constants. They become "inlined" if it's obvious
> to perl that the return value is indeed a constant.

You can also, if you don't want to "use constant" (and can't or won't 
use lexical variables) alias your package variables to constant values:

  package Foo;

  use strict;
  use vars qw($bar);

  *bar = \"This is a constant string\n";

  package main;

  print $Foo::bar;                      <-- this would work
  $Foo::bar = "This is a new value\n";  <-- this would die


- Matt


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