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From: reino@cs.eur.nl (Reino de Boer)
Newsgroups: comp.lang.misc,comp.software-eng
Subject: Re: An Interesting View of "Strong" Vs. "Weak" Typing
Keywords: typing, Ada, Lisp, definitions, evidence
Message-ID: <1990Jan5.084746.17836@cs.eur.nl>
Date: 5 Jan 90 08:47:46 GMT
References: <641@ajpo.sei.cmu.edu>
Organization: Erasmus Universiteit Rotterdam, dept. CS (Informatica)
Lines: 37

eberard@ajpo.sei.cmu.edu (Edward Berard) writes:

>I would be interested in getting your reaction to the
>following quotes from one of respondees:

>>>         object-oriented programming. Smalltalk has, in effect, no
>>>         types, but there are typed extensions to Smalltalk, e.g.,
>>
>> Again, CL and Smalltalk have *run-time* types - restrictions on
>> the use of *objects* during program *execution*.  Languages such
>> as Ada have *compile-time* types - restrictions on the use of
>> *identifiers* during program *compilation.*

I tend to agree with `>>>' that Smalltalk has no types. The feeling of
run-time types is actually the `not being able to respond to certain
messages'.

>Are there any references documenting the benefits of strong vs. weak
>typing? What are your reactions to the definitions given?

My reaction:
I think languages like Miranda have shown us that the effects of
run-time type-checking can for a very large part be accomplished by
compile-time evaluation of possible types. Although something can be
said in favor of the statement
	all interpreters (CL, Smalltalk, etc.) by definition do only
	run-time checking (not being able to compile at all).

P.S. Thank you for your overview of Object-Oriented Design.

Reino


-- 
Reino R. A. de Boer
Erasmus University Rotterdam ( Informatica )
e-mail: reino@cs.eur.nl