Path: utzoo!attcan!uunet!fernwood!apple!olivea!mintaka!bloom-beacon!eru!hagbard!sunic!kth.se!news
From: d87-mra@dront.nada.kth.se (Magnus Ramstr|m)
Newsgroups: comp.object
Subject: Re: Do we really need types in OOPL's?
Message-ID: <1990Sep28.070257.8676@kth.se>
Date: 28 Sep 90 07:02:57 GMT
References: <0yw10qr@Unify.Com> <411@eiffel.UUCP> <736@tetrauk.UUCP> <1990Sep25.135145.3460@kth.se> <3832@osc.COM>
Organization: Royal Institute of Technology, Stockholm, Sweden
Lines: 31

In article <3832@osc.COM> tma@osc.UUCP (Tim Atkins) writes:
>In article <1990Sep25.135145.3460@kth.se> d87-mra@dront.nada.kth.se (Magnus Ramstr|m) writes:
>
>>
>>This can be achieved in a strongly typed OOPL by having one class as the
>>ancestor of all other classes, letting your variables refer to that class
>>and using virtual messages only. Therefore a strongly typed OOPL can
>>be transformed into a weakly typed one, while the reverse is not true.
>
>	This is not really the case.  In a dynamically typed language
>any message can be sent to any object.  In a staticly typed language with
>a common base class only messages understood by the base class may be sent.
>
Ok, I was unclear. The statement above is ment to be theoretical. The base
class must of course understand all messages, if only by invoking empty
methods.
>
>	I also disagree that "strong" typing cannot be simulated in a 
>dynamically typed language.  Type or even protocol tests can be inserted at
>will and could probably be automated in fairly clever and efficient fashion.
>handling these cases.
>
Again, theoretical. I wrote transform into, not simulate. A dynamically
typed language can not provide compile-time type checking, as I am sure
you would agree with. But, my article was unclear on the details, and I
thank you for pointing this out.
>
>Tim Atkins
>

d87-mra@nada.kth.se (Magnus Ramstr|m). Student @ Dep. of Computer Science.