Re: Static Variables in Perl

The best way to do this is probably to just inherit accessor and mutator methods, and not try to alter the class data directly.

package Parent;

our $knob = 1;

sub knob { 
    my $class = shift;
    $knob = $_[0] if @_;
    return $knob;
}

package Child;

use base 'Parent';

# inherits knob method
[download]

That way, calling Parent->knob or Child->knob will get and set the same package global in Parent. To make it safer, you could make $knob a lexical, so it's only visible via the method call.

Update: Better mutator code per Tanktalus's comment.

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Re^2: Static Variables in Perl by Tanktalus (Canon) on Mar 30, 2006 at 20:32 UTC
Minor tweak: `$knob = $_[0] if @_;` [download] That way, `Parent->knob()` is an accessor, while `Parent->knob(undef)` is a mutator that sets the $knob to undef. Slightly better: `if (@_) { # check that $_[0] is allowed. $knob = $_[0]; }` [download] but that's only if there are invalid values you want to block.	[reply] [d/l] [select]