NAME
    Callback - object interface for function callbacks

SYNOPSIS
            use Callback;

            my $callback = new Callback (\&myfunc, @myargs);

            $callback->call(@some_more_args);

DESCRIPTION
        
Callback provides a simple interface for function callbacks.  It 
would be possible to provide nearly all of the functionality using
inline code references.  Callback was written before 
inline code references were added to perl.
    What callback does provide is a simple interface for common situation:
    passing around a function.

    When a callback is constructed, a base set of arguments can be provided.
    These function arguments will preceed any arguments added at the time
    the call is made. When the function to be called is a reference, be sure
    to put $this as the first argument!

TRACING
            use Callback qw(@callbackTrace);

    If you're writing a debugging routine that provides a stack-dump (for
    example, Carp::confess) it is useful to know where a callback was
    registered.

            my $ct = 0;
            while (($package, $file, $line, $subname, $hasargs, $wantarray) = caller($i++)) {
                ...

                if ($subname eq 'Callback::call') {
                    print "callback registered $Callback::callbackTrace[$ct]\n";
                    $ct++;
                }
            }

    Without such code, it becomes very hard to know what's going on.

COPYRIGHT
    Copyright (C) 1994, 1998, David Muir Sharnoff. All rights reserved.
    License hearby granted for anyone to use this module at their own risk.
    Please feed useful changes back to muir@idiom.com.