Re^3: Am I evil for doing this?

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Re^4: Am I evil for doing this? by jdporter (Paladin) on Mar 11, 2005 at 02:16 UTC
It's so much less evil, in fact, that it's actually allowed by strict. Yes; but there is considerable disagreement as to whether this ought to be the case. Some very respectable occupants of the Perl pantheon believe that it's an unnecessary and arbitrary loophole. If you wanted to be extra careful, you could use UNIVERSAL::can... That actually depends on what you want. If you want to allow the possibility that the method could get handled by AUTOLOAD, then you should not pre-test with UNIVERSAL::can. There's also an issue with how you call `can`. I figure, if you don't know whether the object can handle the $method, then you might not know if it's even an object; so to avoid the error potentially resulting when $self is not an object, I usually do the following, though unfortunately it isn't as pretty: `if ( UNIVERSAL::can( $self, $method ) ) {` [download]	[reply] [d/l] [select]
Re^5: Am I evil for doing this? by ihb (Deacon) on Mar 11, 2005 at 12:39 UTC
`if ( UNIVERSAL::can( $self, $method ) ) {` That too, unfortunately, isn't good either, if an autoloading class properly overloads `can`. Imho, a class that uses `AUTOLOAD` also has the obligation to overload `can` accordingly. If it doesn't that class should be fixed, not mine, if that's an option. I prefer to do `can` checks like `if (blessed($self) \|\| ! ref($self) and my $code = $self->can($method)) + { $self->$code(...); }` [download] if I need to handle `$self`'s that can't invoke methods. Update: Forgot to mention `&blessed` comes from Scalar::Util. `ihb` See perltoc if you don't know which perldoc to read!	[reply] [d/l] [select]
Re^6: Am I evil for doing this? by jdporter (Paladin) on Mar 11, 2005 at 14:24 UTC
That's an interesting possibility too. I've never run into it yet, but I'm sure it will bite me sooner or later!	[reply]
Re^4: Am I evil for doing this? by ihb (Deacon) on Mar 11, 2005 at 12:34 UTC
I prefer to not do the method-lookup twice and use the code reference returned by `can`: `if (my $code = $self->can($method)) { $self->$code(...); }` [download] `$self->$code(...)` where `$code` is a subroutine reference is equivalent to `$code->($self, ...)`; you can even do `[]->$code` or `undef()->$code` if you want. `ihb` See perltoc if you don't know which perldoc to read!	[reply] [d/l] [select]
Re^4: Am I evil for doing this? by Anonymous Monk on Mar 11, 2005 at 09:44 UTC
It's so much less evil, in fact, that it's actually allowed by strict. That's probably the most evil statement in this entire thread. It suggests that 'strict' is this omniscient, benign being that flawlessly decides what's good for you and what not. It's not. Sometimes disabling strict is the right thing to do (because it allows you to do something that isn't otherwise possible, or it allows you write easier to understand code). Pleasing 'use strict;' should not be a design goal. Of course using "use strict;" is usually a good idea.	[reply]
Re^5: Am I evil for doing this? by Mugatu (Monk) on Mar 11, 2005 at 17:06 UTC
It suggests that 'strict' is this omniscient, benign being that flawlessly decides what's good for you and what not. That wasn't my intent. The things allowed and disallowed by strict are generally thought out and usually embody common sense. Of course, it is not the only way to fly, but it is usually a helpful guideline of what is a good idea and what is not.	[reply]