Smalltalk and CORBA
Ralph E. Johnson
johnson at cs.uiuc.edu
Fri Dec 11 16:48:31 UTC 1998
At 11:29 AM 12/9/98, Stephen Pope wrote:
>I'm glad that there are several others interested in CORBA ORBs for Squeak. The
>basic prerequisites that are currently still open issues include:
> (1) Weak references and collections;
> (2) First-class exceptions (including unwinding); and
> (3) a ParserGenerator.
>(1) has been recently added to Squeak by Andreas Raab.
(2) has been done by Craig Latta
(3) would be solved by a port of T-gen. Some people suggested
having some students write a parser generator as a class project.
First, if the goal is CORBA, it would be a lot easier to write an
IDL parser by hand (recursive descent) than to write a parser generator.
T-gen has its problems, but it is not a bad parser generator. I do not
believe that an undergraduate working for 4-6 months will produce anything
nearly as good. Don Roberts has been using it for a few years and is
thinking about writing a new parser generator that fixes T-gen's
problems, but he keeps telling people here to just use T-gen and
not to wait on getting a new one, nor to try to make one themselves
unless they are really into parser generators.
>Jeff Eastman (the author of both H-P DistributedSmalltalk and DNS
>SmalltalkBroker [STB]) has expressed great interest in porting STB to Squeak,
>but is waiting for the 3 facilities mentioned above to be made available first.
It seems odd to me for people to be talking about making an ORB when
Mr. Distributed Smalltalk, a guru of ORBs and master object designer,
has volunteered to do it! By all means, lets see if Jeff will do it.
We should figure out what is in his way and get rid of it, not try to
compete with him.
It seems to me that the main things that people can do to help are
1) test weak pointers and report errors to Andreas
2) test Craig's exception handling code and report errors to him
3) port T-gen
1 and 2 are in fact great things for large numbers of people to do
in parallel. Testing new packages is a good way of learning how
they work. If you have ever wondered about weak pointers or exception
handling, try retrofiting some of your programs. Or retrofit the
image. You might try to use weak pointers to close a file when you
are no longer using it. You might go through the image and put
exception handling in, writing lots of test cases to make sure you
don't break anything and that Craig's code works, of course. Even
if you don't produce any useful code or find any errors, you will
learn a lot.
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