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Ovid (2709)

Ovid
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Stuff with the Perl Foundation. A couple of patches in the Perl core. A few CPAN modules. That about sums it up.

Journal of Ovid (2709)

Tuesday January 04, 2005
04:20 PM

Would you shoot me for this?

[ #22566 ]

I was going to release a module named "Aliased" which would alias long class names to short ones. However, it's only for OO modules , it sort of alters compile-time behavior so one might think of it as a pragma, and "class" is not a keyword. Thus, I could do this:

use class 'My::Company::Namespace::Customer';
use class 'My::Company::Namespace::Preferred::Customer', as => 'Preferred';

my $cust = Customer->new;
my $pref = Preferred->new;

My immediate reaction was "no!", we don't want to do that. Then I realized I couldn't think of a reason why. Can you? I certainly don't want to release that and make people mad (though Theory pointed out that "class" doesn't indicate that anything's getting exported to the current namespace).

Side note: the "as" key in the import list is important because there's a separate "import" key in case you need to pass args to the module's import() method.

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  • That's an excellent idea! Now when people submitting requests to modules@perl.org complain that they want their pet module to have a short name cos it saves typing in their programs (at the expense of being meaningful in the global hierarchy) this can provide a solution.

    It's also handy when a module changes its name — just change the use line, and leave other references to the class alone.

    Smylers
    • I know I'll get biatch slapped for saying this; and it's not meant as a flame; but... Isn't submitting namespace requests to modules@ worthless now a days? Isn't there an overall push/acceptance to abandon maintanence of "registered' modules and the modules list @ http://www.cpan.org/modules/00modlist.long.html? http://www.perldiscuss.com/article.php?id=2803&group=perl.module-authors http://www.mail-archive.com/module-authors@perl.org/msg01752.html
      • Isn't submitting namespace requests to modules@ worthless now a days?

        From the the point of view of having an official list of registered modules, quite possibly. But the process definitely is useful in moderating modules' names.

        brian d foy in particular is good at spotting when a module has been submitted with an awkward name and suggesting a better one, and in general the suggestions are acted upon. That makes Cpan a more pleasant place for all of us.

        Smylers

  • On the one hand, good job. You should beat your programming language until it fits your domain.

    On the other hand, it's Java all over again. Every time I look at a Java program, I see statements like import java.io.* and the like. A few lines later, I see references to classes I've never seen before from one package or another, and I don't know where to go when I'm looking up methods on some interface like XMLReader or some class like HashMap. Because the package prefixes are stripped, I've lost all co

  • use class 'My::Company::Namespace::Customer';
    use class 'My::Company::Namespace::Preferred::Customer', as => 'Preferred';
     
    my $cust = Customer->new;
    my $pref = Preferred->new;

    So... what would it do if you had not used 'as => 'Preferred' in the second instance?

    It looks like it is "aliasing" the module name (the last part) but that is the same as the previous module... so would it re-alias Customer?

    And... does it alias all modules that are used after calling it? I think I'd really, really

    • It only aliases what you tell it to alias, so no worries there. Also, the entire point of this is to keep things really, really simple. Dirt simple. Making it all OO defeats that. All this module really does (mostly) is to use the package in question and then insert a sub into your namespace that returns the name of the module.

  • You might want to avoid using class so that if/when someone writes (or maybe someone has already written) a Perl6:: module that supports class as a keyword folks won't be inviting confusion by trying to use both that module and yours.

    Obviously "don't use that name, because someone else might" could be said of any name, but I think a potentially very popular name like 'class' might be worth extra caution.

    Then again, if you call it 'class', someone who hates the name can write a thin wrapper calling it what
    • Hi Matt. I'm going to call it "aka.pm" because it's short and that's a name that received fairly decent support on the module author's list. I was also hesitant about the Perl 6 issue, oddly enough. I'll probably have it uploaded in the next day or two unless there's some strenous objection from the PAUSE admins.

  • Sorry Ovid, but this is an abomination. It kind of sums up many of the problems with Perl culture: obsession with syntax over utility, willful use of obscure features like using the import list for other things, and a desire to make everything REALLY short. Give the module a normal name, call the alias method like a normal method, and give intermediate perl programmers a chance in hell of understanding your code. Otherwise, it belongs in Acme::.
    • I fear that you are in the minority. Though many have objected to the name -- leading me to change it -- you're the only person who has objected to the idea of the module.

      The inspiration for this code was a module named "Aliased" that Rentrak [rentrak.com] uses extensively in their code. (They have graciously allowed me to duplicate the functionality of the code.) The reason I mention this is because while the code is new, the interface is not and it has withstood the test of time for very large scale systems (enterp

      • I think you're misunderstanding me. I don't object to the module, only to the interface. I think it should have a simple interface with no obscure import() subversion and no pragma-like class names. The concept of aliasing is clear enough -- it's that API you came up with that I don't like.
        • Yes, I did misunderstand you. However, even though there are a couple of people who objected to the interface, I fear you're still in the minority. As I mentioned previously, I and a number of other programmers have been using a virtually identical interface for so long without any problems (and with strong benefits) that I'm still quite comfortable with the interface.

          You are someone who I generally pay extra attention to given my respect for your abilities. In this case, I must disagree due to extens

    • I was going to post a flame about how the whole point of programming language design is to obsess over syntax in the name of achieving greater utility. That's what gave us idioms like 'open or die' and foreach loops over hand-compiling tail recursive forms.

      But I see that your clarification, and yes, the abuse of the import list is quite horrid.

      Perl is a dynamic language. There's no reason why the magic fiddling must happen at compile time, nor is there any reason why it the aliasing must use a use sta

      • Well, my thought is pretty straight-forward: the current code I have implemented not only works, it fits very naturally with current Perl syntax. I can't say that I like the syntax of how I handled importing, but that's not the common case. The important thing is that the common case be handled easily. The more programming people do, the more they want the common things to be short-n-sweet.

        My code is ready to be uploaded and I'm merely waiting for last minute objections from the modules@cpan.or

        • The only reservation I have is about my use of UNIVERSAL::can.

          As well you should. The right code is even shorter and clearer.

          • Silly me. For some stupid reason I thought I shouldn't use $package->can('import') because there's no guarantee that there's an import method. Mentally I thought "there's no guarantee that package can('can') and that might throw an error." It's weird how muddled my mind substituted "can" for "import" in that method call :/

      • I like that API much better. My beef with the original API is that it uses pragma-like names and a non-obvious use of import (which is unfortunately catching on because of Test::More), and all for the sake of syntax rather than added functionality. To me, it looks like a disregard for the larger effects on the community, i.e. if everyone did crazy stuff like this to get a particular syntax for their modules, CPAN would be a total disaster. I have also seen this kind of thing get people into trouble, as i
  • Like the idea. The name not so good. Two objections. One: there's got to be a better use for class.pm. Two: it doesn't say anything about the aliasing/shortening aspect of the module. If I was to guess what class.pm was I would guess it was something for writing a class.
  • Why does this need an entire module?

    use constant Customer => 'My::Company::Namespace::Customer';
    use constant Preferred => 'My::Company::Namespace::Preferred::Customer';

    my $cust = Customer->new;
    my $pref = Preferred->new;

    I've used this not-even-a-trick on several occasions, FWIW.

    Note how it makes no difference in the actual code, just makes effective use of what's already in the core. (And you could even do without constant.pm using prototyped subs, but that is too opaque for my tas