Perl 5.8.0 and Attribute::Handlers

bronto has asked for the wisdom of the Perl Monks concerning the following question:

So 5.8.0 is out.

As always, the first document I dig into when a new perl comes out is perldelta. In section New Modules and Pragmata we have:

Attribute::Handlers, originally by Damian Conway and now maintained by Arthur Bergman, allows a class to define attribute handlers. Both variables and routines can have attribute handlers. Handlers can be specific to type (SCALAR, ARRAY, HASH, or CODE), or specific to the exact compilation phase (BEGIN, CHECK, INIT, or END).

Anyway, in the same document, you read:

The my EXPR : ATTRS syntax now applies variable attributes at run-time. (Subroutine and our variables still get attributes applied at compile-time.) Note that the new semantics doesn't work with the Attribute::Handlers module (as of version 0.76).

The question is: how do you read these?

Attribute::Handlers is bundled with perl, and hence standard: trust it but don't use it for lexical variables;
Attributes specification and usage is still in fieri: experiment with them but don't trust them, even though Attribute::Handlers is there;
use attributes (and Attribute::Handlers), but be warned that...;
don't use attributes at all, they are evil and unuseful!!!
bronto is a plain dumb and this question doesn't deserve my attention.

Any drop of wisdom for me?

Ciao!
--bronto

# Another Perl edition of a song:
# The End, by The Beatles
END {
  $you->take($love) eq $you->made($love) ;
}

Comment on Perl 5.8.0 and Attribute::Handlers

Replies are listed 'Best First'.
Re: Perl 5.8.0 and Attribute::Handlers by hakkr (Chaplain) on Jul 24, 2002 at 13:54 UTC
sub question, What are they for and why would you want to use them. Way I am understanding it is you can assign subroutines to a variable. So a variable can have a subroutine associated with it without being blessed into a class. And the subroutine called will be dictated by the type of the variable?	[reply]
Uses for Attributes (was:Re: Re: Perl 5.8.0 and Attribute::Handlers) by Corion (Patriarch) on Jul 24, 2002 at 16:12 UTC
Attributes are cool whenever out-of-band data is required. Some examples : I have a toy application here, where I use attributes to specify access levels for subroutines. If your application consists of a chain of list-munging subroutines, you can easily add tracking information as which routine touched which item without having to change/adapt every routine and without conflict with the output. The always present compiler hints or runtime type enforcement can also be implemented via attributes (like the `:Integer` attribute), but of course, this is also out-of-bound information about your "data" (this time, your program is regarded as data by `perl`) `perl -MHTTP::Daemon -MHTTP::Response -MLWP::Simple -e ' ; # The $d = new HTTP::Daemon and fork and getprint $d->url and exit;#spider ($c = $d->accept())->get_request(); $c->send_response( new #in the HTTP::Response(200,$_,$_,qq(Just another Perl hacker\n))); ' # web` [download]	[reply] [d/l]
Re: Re: Perl 5.8.0 and Attribute::Handlers by bronto (Priest) on Jul 24, 2002 at 15:02 UTC
What attributes are for? Uhmmmm... why you ask me? The camel book (3rd edition, page 745) shows `my num PI : constant = atan2(1,1) * 4` as an example and tells briefly about other possible uses. Why would I use them. I came around them in 180455 and replies. Yesterday night I read perldelta, today I was digging into the code and docs of Attribute::Protected. I found it interesting, but since it relies on Attribute::Handlers it would be interesting to know if it is safe to write production code with it. attributes reports the usage attribute declaration for variables is still experimental. What I would like to have is, say, a measure of how much experimental attributes are: is it safe to play with them in subroutines now? Is it not? Code that uses Attribute::Handlers is reliable or is expected to break in the short/medium term? Ciao! `--bronto` # Another Perl edition of a song: # The End, by The Beatles END { $you->take($love) eq $you->made($love) ; }	[reply] [d/l]
Re: Perl 5.8.0 and Attribute::Handlers by stefp (Vicar) on Jul 29, 2002 at 21:00 UTC
$A++, always surfing the bleeding edge of technology demonstrates the use of attributes... and currying to add some condiments. `Constante usée pour rien Stéphane 8-jui-2002 use constant; my constant $A++ De l'utilisation des attributs Stéphane 8-jui-2002 sub _ : lvalue { $A }; ++_(); D'une autre utilisation des attributs Stéphane 8-jui-2002 use Attribute::Handlers; sub _ : ATTR(SCALAR) { ${$_[2]}++ } my $A : _ ; $A; La cuisine au curry (par Ed) Stéphane 14-jui-2002 use Perl6::Currying; sub add($a, $b) { $a + $b }; $incr = &add.prebind(a=>1); $A = $incr->($A)` [download] -- stefp -- check out TeXmacs wiki	[reply] [d/l]
Re: Perl 5.8.0 and Attribute::Handlers by imoore (Novice) on Jul 25, 2002 at 06:59 UTC
I think you are expecting too much as 5.8.0 is the experimental developers release, not the stable release; this inconsistency requires further development to resolve...	[reply]
Re: Re: Perl 5.8.0 and Attribute::Handlers by IlyaM (Parson) on Jul 25, 2002 at 10:18 UTC
5.8.0 is stable release. Do not confuse it with 5.7.xx and previous 5.8.0 release candidates which are experimental developers releases. -- Ilya Martynov (http://martynov.org/)	[reply]