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Postings from June 2001
On Tue, Jun 05, 2001 at 02:42:01PM -0400, John Porter wrote: > > You don't want to try holding up prototypes and dereference checks to > > Java's typing system and try to claim its in the same league, or even > > the same sport. > > As I said before, it boils down to the fact that perl's notion of a > "type" is different from other languages. It *does* check these > types, and it "casts" very opportunistically. Ok, let's call them types for a moment. A) You can't meaningfully define new types. This makes it pretty much useless as a typing system. B) The system's only awareness of OO is that objects must be references, otherwise anything goes. Even if prototypes worked on methods you still couldn't specify which objects you want. C) To call Perl's differenciation between scalar, array, etc... references a typing system is like calling C's differenciation between structs, arrays and scalars a typing system. You may be able to draw analogies, but they don't serve the same purpose. Yes, there is some actual type casting going on between strings and numbers and various internal scalar types, but its mostly behind the scenes. What Perl does with references is basic sanity. Using a scalar reference as an array ref doesn't really have meaning, for example. A real typing system is a layer of *additional and arbitrary* (from a purely syntactical PoV) enforcement on top of this. Typed data could mix and could have meaning (a variable of type Velocity could be used where a Price is wanted, they're both numbers) but you disallow it because it doesn't fit in with the reality you've defined in your program. Perl doesn't have a built-in typing system comparable to what most of other languages have, and its not healthy to delude ourselves into thinking we have one. The lack isn't much of a problem, Perl doesn't really need it and it causes all sorts of complications (as noted in the other threads). Wouldn't hurt to have one, though. I have a feeling we're arguing somewhat different things here. -- Michael G. Schwern <schwern@pobox.com> http://www.pobox.com/~schwern/ Perl6 Quality Assurance <perl-qa@perl.org> Kwalitee Is Job One OH GOD!! It's LINUX! All you Linux fanboys go wild! It never crashes! It'll wash your underpants! It'll eat your dog for you, if you want your dog to be eaten! It'll make you attractive and smell good and... it'll... uh... uh. Man, I'm so sick of this shit. http://www.goats.com/archive/000602.htmlThread Previous | Thread Next