in reply to Re: Re: Re: Callback Design
in thread Callback Design

Ah, you just showed me something cool, that I can do without the 'sub' declaration if I prototype the callback-setter.

But I guess I'm not being very clear as to my primary objective. I would like to have something like the following:

package MyModule; my $callback; sub set_callback { $callback = shift; } sub exec_callback { # the next three lines don't work, but they are indicative of what I + would like # to see happen... i want $name, $street, $city, $zip to be made ava +ilable as package # globals to the anonymous callback sub... in other words, I don't w +ant the callback # to execute in it's own package, I want it to execute in MyModule:: +ThrowAway package MyModule::ThrowAway; our ($name, $street, $city, $zip) = @_; &$callback(); package MyModule } package main; # set callback to check that name and zip are both correctly formatted # notice that callback sub assumes that $name and $zip have been set f +or it, not # passed in @_ # MyModule::set_callback(sub { $name =~ /^[a-zA-Z\s]+$/ and $zip /^\d+$/ + }) MyModule::exec_callback('Bob', '600 1st St.', 'Beverly Hills', 90210);
Now that I think about it, this could never work under use strict, since $name and $zip are undeclared at the time the callback sub is formed.

update: cleared up a few confusing things in my code

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Re: Re: Re: Re: Re: Callback Design
by saucepan (Scribe) on Jan 16, 2001 at 06:46 UTC
    Is there some reason why you couldn't just have your module export the variables you'd like to expose to it's users? :)

    package MyModule; use vars qw(@ISA @EXPORT_OK $name $street $city $zip); BEGIN { @ISA = qw(Exporter); @EXPORT_OK = qw($name $street $city $zip); require Exporter; } my $callback; sub set_callback(&) { $callback = shift } sub exec_callback { local(($name, $street, $city, $zip) = @_); $callback->(); } package Main; BEGIN { import MyModule qw($name $street $city $zip) } MyModule::set_callback { $name =~ /^[a-zA-Z\s]+$/ and $zip =~/^\d+$/ } +; MyModule::exec_callback('Bob', '600 1st St.', 'Beverly Hills', '90210' +) and print "Record is valid.\n";
    Once MyModule was moved into it's own file, you could replace the ugly BEGIN { import ... } line with just use MyModule qw($name $street $city $zip).

      Good point, but I would ideally like to avoid polluting my module caller's namespace with a bunch of variables. If it came down to choosing between this and $$_{street}, I would probably go with the latter. What do you think?