Path: utzoo!attcan!uunet!mcsun!ukc!mucs!m1!bevan From: bevan@cs.man.ac.uk (Stephen J Bevan) Newsgroups: comp.object Subject: Re: Do we really need types in OOPL's? Message-ID: Date: 25 Oct 90 11:22:31 GMT References: <1990Oct9.190813.23402@ux1.cso.uiuc.edu> <2444@runxtsa.runx.oz.au> <1990Oct19.180646.8649@ux1.cso.uiuc.edu> <45940@apple.Apple.COM> Sender: news@cs.man.ac.uk Distribution: comp Organization: Department of Computer Science, University of Manchester Lines: 34 In-reply-to: lins@Apple.COM's message of 24 Oct 90 16:14:02 GMT In article <45940@apple.Apple.COM> lins@Apple.COM (Chuck Lins) writes : > A compilation of a few seconds (or even minutes) costs > far far less than the hours or days it takes to thoroughly test software. I'm not sure I understand the above as it seems to imply that using strong/static typing means you don't have to test your software?? Given that you do test your software (no matter what sort of typing is used) the question is what % of errors in the dynamic system are due to typing problems and not to general logic errors. You could say that anything other than 0% shows that dynamic/weak typing is ``wrong''. However, I see the small % of typing errors, (which will be caught during testing :-) as a small price to pay for the flexibility of the language. But then again, I'm only a student in a ivory tower :-) IMHO languages like ML (and also Haskell) go a long way towards providing the sort of type protection I would like in a language. However, both of these are functional languages. I have yet to see an equivalent in the OO world. (Eiffel tries hard, but its not there yet). This doesn't mean I wouldn't use languages like C++ or Eiffel, I just wouldn't hold up the strong typing as that much of an advantage over languages like Smalltalk/CLOS. IMHO the main advantage of strong typing is to help the compiler to generate more efficient code. However, the work done on SELF would seem to suggest you can get equivalent speeds without the need of typing. (More power to their collective elbows I say). Just rambling while my program compiles, Stephen J. Bevan bevan@cs.man.ac.uk