use Perl

• I don't get the set_method things (Score:1)

  by Alias (5735)

  I mean, ok, I see some cases where it would be useful.
  
  But it seems to me that 90% of the time, you don't really NEED the ability to mutate the objects after creation time, especially with that sort of thing. You'd almost always set it at creation time.
  
  Mutators just adds more (potentially illogical) states (and thus potential bugs).
  
$mean = Mean->new( skipinf => 1, trim => 1 )->on( @data );

package Mean;

use Object::Tiny qw{
        skipinf
        trim
};

sub o
  • Re: (Score:1)

    by educated_foo (3106)

    My broader point was that the current fad of calling everything a "DSL"can exist only because people are thoughtless with interfaces and/or have been trained to create painful ones. I agree that setters are probably unnecessary in this case, but your cleaner code nicely demonstrates one of my own interface pet peeves: Blah->new(@stuff)->doit. There's always at least one in the CPAN queue -- see Sudo this morning. Doing this is almost always a mistake indicative of someone having been told that "obj
    • Re:I don't get the set_method things (Score:1)

      by Alias (5735) on 2007.05.22 23:05 (#55243) Homepage Journal

      > Sometimes a function is just a function.
      
      Sometimes, yes. And it's true people get bitten by the object fad.
      
      But as you scale is can be very advantageous to have the option of encapsulating a function and moving it around.
      
      It's not really safe to do this with a raw code-ref, because a coderef could be anything at all and is tied to the Perl instance. A data structure is far more flexible.
      
      "Process Objects" (objects that describe a computational process) allow you to do things that functions can not do.
      
      For example, File::Find::Rule objects essentially describe computational filters. Sure you could have it as a function, but because it's an object, it can be easily passed as a filter to other functions that operate on file sets.
      
      And those functions can VALIDATE that they are recieving a filter object.
      
      Even more abstracted from that, look at the Process.pm family.
      
      Objects that a built as Process.pm subclasses are capable of some very very cool things, such as being backgroundable, are able to run in a seperate Perl instance, are able to run in a different Perl VERSION, or in my favourite case, can be serialized into files, and be distributed across multiple processing nodes.
      
      That said, Process.pm objects describe BOTH the process and the data in a single object... (or at least have a pointer to the data).
      
      Most of the time a verb (function) should just be a verb, but sometimes having a verb as a noun (object) can be very very handy.
      
      But yes, many people and languages (Java) like to go a bit over the top by making everything a noun...
      
      There's a time and a place for both.

      Reply to This

      Parent

      • Re: (Score:1)

        by educated_foo (3106)

        "Process Objects" (objects that describe a computational process) allow you to do things that functions can not do.

        IMHO they get the defaults wrong most of the time. If you amortize over all the people using a module, it's less trouble for those who need them to go through the full pain of either serializing functions through e.g. Storable or doing a custom solution, than for everyone to use a ghastly "OO" interface, or roll their own. Distributing a module on CPAN is a real win when it will save time
      • Re: (Score:1)

        by zby (4817)

        Many of those advantages you mention are also available via closures. Other languages don't have true closures - so they have to do that in OO - but we have choice. HOP shows that a more functional approach also works.