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27 lines
1.4 KiB
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27 lines
1.4 KiB
Plaintext
The Class:Multimethod module exports a subroutine (&multimethod) that can
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be used to declare other subroutines that are dispatched using a algorithm
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different from the normal Perl subroutine or method dispatch mechanism.
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Normal Perl subroutines are dispatched by finding the appropriately-named
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subroutine in the current (or specified) package and calling that. Normal
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Perl methods are dispatched by attempting to find the appropriately-named
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subroutine in the package into which the invoking object is blessed or,
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failing that, recursively searching for it in the packages listed in the
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appropriate @ISA arrays.
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Class::Multimethods multimethods are dispatched quite differently. The
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dispatch mechanism looks at the classes or types of each argument to the
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multimethod (by calling ref on each) and determines the "closest" matching
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variant of the multimethod, according to the argument types specified in
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the variants' definitions (see "Finding the "nearest" multimethod" for a
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definition of "closest").
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The result is something akin to C++'s function overloading, but more
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intelligent, since multimethods take the inheritance relationships of each
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argument into account. Another way of thinking of the mechanism is that it
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performs polymorphic dispatch on every argument of a method, not just the
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first.
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WWW: http://search.cpan.org/dist/Class-Multimethods
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Author: Damian Conway <damian@conway.org>
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