why do you think UNIVERSAL::isa returning ref type is a bad design (the perl developers obviously don't think so...)? using UNIVERSAL::isa to establish ref type allows one to turn the array ref that used to be passed to a method into a blessed object (preferably a tie in this case to intercept internal data access) that lists the fictitious class 'ARRAY' as a (completely abstract) superclass (or interface if you prefer).

i do not think this is evidence of a bad design at all. it is just necessary to relax one's OO prejudices/convictions a little (which for perl OO, shouldn't be difficult ;-) ). on the contrary, i feel the 'ARRAY', 'HASH', etc pseudo classes ought to be used as marker interfaces (think java's Serialisable or Cloneable) to indicate the capability to be deferenced as a variable of that type (which, if the object supports a tie interface or has overloaded magic is really a method call in disguise). in other words, if isa( $thing, "ARRAY" ) returns true then $thing can be used as if it were a native array, regardless of exactly what $thing is, or how it implements array retrieval/storage. hooray for encapsulation *and* some nice parametric polymorphism as well.

and FWIW, using isa() in this manner is used in quite number of cpan modules.

In reply to Re: Re: Re: Re: Is "ref $date eq 'ARRAY'" wrong? What a mess! by d_i_r_t_y
in thread Is "ref $date eq 'ARRAY'" wrong? by bronto

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