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Re^5: More Macro work...out to export a definition to next-outer level?

by ikegami (Pope)
on Oct 01, 2010 at 16:19 UTC ( #862981=note: print w/ replies, xml ) Need Help??


in reply to Re^4: More Macro work...out to export a definition to next-outer level?
in thread More Macro work...out to export a definition to next-outer level?

I think there's a confusion in terms. I'm using class var to mean global to the whole class and each instance of the class.

The confusion is yours. You've been saying the above, but you haven't been doing the above. Like I said, your instance constructor populates the globals instead of the instance.

If there's only ever one instance, what you have a singleton, and you've made a mess of things.
If there can be multiple instances, your code is broken.

There shouldn't be multiple initializations

Then they should be initialised outside of any function.

Does this clear anything up?

No. I understood fine all along.


Comment on Re^5: More Macro work...out to export a definition to next-outer level?
Re^6: More Macro work...out to export a definition to next-outer level?
by perl-diddler (Hermit) on Oct 03, 2010 at 15:45 UTC
    I don't know if you are still seeing replies, since I don't know how to get notified of replies to my replies other than to go find each thread I've written in and look for them, BUT, I'll try to clarify again. In my setup, I'm doing this (not copied from code, but written for demonstration, so if everything doesn't run, that's why):
    package MyPackage; our $global=0; sub global { shift; $global=$_[0] if @_; $global; } sub instance { my $this=shift; if (@_) { $this->{instance}=$_[0]; ++$global; } $instance; } sub new { my $package=shift; bless {},$package; } } package main; my $package = new MyPackage(); #main *doesn't* know what vars are per-class or which are per-instance +. # that's an implementation detail the caller doesn't know about # so all calls are called through method calls. $package->instance(1.7); print "vars created = ",$package->global; ... # reset MyPackage counter to globally reset counter for all users # (not normal used; be available for better user control of counting.. +. $package->global(0); ...
    Is your complaint that I'm setting my global in a method call? That is intentional. In this situation, callers don't know the details of some variables -- whether they are per-class or per-instance. I am aware, that a caller could call an initializer function more than once. But in the use of the class, this would be an abnormal occurrence -- supported for development purposes, but not normally used.

    Later, if I thought it was necessary, I could change the global definition and make some 'global_readonly', that only provides a 'get' function if I thought it necessary, but for now, I'm providing both.

    I feel like we are playing 20 questions -- I keep trying to see if 'X' is what you are talking about. You keep saying 'wrong', 'its a mess'. But you don't clearly explain why its a mess. This isn't as helpful for me as your first explanation was on my prior question -- sorry.

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