Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!usc!brutus.cs.uiuc.edu!psuvax1!rutgers!cmcl2!esquire!yost
From: yost@esquire.UUCP (David A. Yost)
Newsgroups: comp.object
Subject: Re: Understanding the Object-Oriented Life-Cycle
Message-ID: <1567@esquire.UUCP>
Date: 13 Nov 89 21:49:21 GMT
References: <5026@internal.Apple.COM> <315@shrike.AUSTIN.LOCKHEED.COM>
Reply-To: yost@esquire.UUCP (David A. Yost)
Organization: DP&W, New York, NY
Lines: 31

In article <315@shrike.AUSTIN.LOCKHEED.COM> aihaug@AUSTIN.LOCKHEED.COM (Daniel A Haug) writes:
>In article <5026@internal.Apple.COM>, chewy@apple.com (Paul Snively) writes:
>
>> Speaking of criticisms, I'm interested in a good discussion on why 
>> statically-typed hybrid languages like Object Pascal and C++ aren't useful 
>> in some contexts where dynamically-typed languages such as Common Lisp 
>> w/CLOS are.  Any takers?
>
>By far (IMHO), the largest advantage to this is in code extensibility,
>or reusability.  ... For example, I need only implement a priority queue
>ADT once.  The algorithm is the >same, but the types can be whatever.

Of course, someone has to say (I'll volunteer) that the following
language attributes are in principle orthogonal:
 1.  statically-typed
 2.  hybrid languages like Object Pascal and C++
 3.  genericity (also known as parameterized types)

You are asking for #3.  C++ has 1 (with escape
mechanisms), 2, and a kluged 3-workaround with
promises of real 3 'real soon now' (my guess 1992).
There do exist languages that have 1 and 3.  Eiffel
for one, and it goes so far as to provide for generic
class parameters to be constrained to be descendants
of a specific type, which you need for static type
checking.  For example,
    HASH_TABLE [ T -> HASHABLE ]
    SORTED_LIST [ T -> COMPARABLE ]
    etc.

 --dave yost