perl-UNIVERSAL-can

The UNIVERSAL class provides a few default methods so that all objects can
use them. Object orientation allows programmers to override these methods
in subclasses to provide more specific and appropriate behavior.
Some authors call methods in the UNIVERSAL class on potential invocants as
functions, bypassing any possible overriding. This is wrong and you should
not do it. Unfortunately, not everyone heeds this warning and their bad
code can break your good code.
This module replaces 'UNIVERSAL::can()' with a method that checks to see if
the first argument is a valid invocant has its own 'can()' method. If so,
it gives a warning and calls the overridden method, working around buggy
code. Otherwise, everything works as you might expect.
Some people argue that you must call 'UNIVERSAL::can()' as a function
because you don't know if your proposed invocant is a valid invocant.
That's silly. Use 'blessed()' from the Scalar::Util manpage if you want to
check that the potential invocant is an object or call the method anyway in
an 'eval' block and check for failure (though check the exception
returned, as a poorly-written 'can()' method could break Liskov and throw
an exception other than "You can't call a method on this type of
invocant").
Just don't break working code.

          

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License: Artistic-1.0 or GPL-1.0+
URL: http://search.cpan.org/dist/UNIVERSAL-can/