[Seaside-dev] Help with stream portability

[James Foster]

All,

As you may be aware, I'm trying to port Seaside 2.9 to GemStone. In  
general things are going well. I've made a couple false starts but  
been set straight pretty quickly in most cases. Thanks for all your  
help and patience. Right now I've got Seaside-Platform pretty well  
ported and tests mostly passing in GemStone. I'm now working on  
Seaside-Core and have things cleaned up enough in Squeak so that there  
is only one test failure--and it is expected. Moving this to GemStone  
has surfaced an issue that looks to be a challenge. I'm at a point  
where I would appreciate some help on a direction to go.

Since the beginning, GemStone has implemented streams with 'position'  
identifying the next object rather than the previous object. That is,  
(ReadStream on: 'abc') position = 1. I'm a strong advocate for ANSI  
compatibility (one of my major triumphs was getting ANSI Exceptions  
into GemStone), and I've entered a GemStone bug to document/track this  
issue.

Obviously it would be trivial to modify #'position' and #'position:'  
to add/subtract the internal value by one before answering.  
Unfortunately, we also need to consider existing code and customers  
and preserve backwards-compatibility and hence the dilemma. I see four  
options:
	1) Fix GemStone;
	2) Have GemStone run a forked version of Seaside;
	3) Create and use a portable method (e.g., #'ansiPosition' or  
#'positionA'); or
	4) Refactor Seaside code so that it does not use these methods.

I don't think I'll be successful in #1 in the short-run and I'd very  
much prefer to avoid #2. I'd be happy to implement #3, but that would  
create a burden on other dialects to add this method. To determine the  
scope of this problem and the cost of #4 I've done a bit of  
investigation.

Based on my review of the Seaside code (Seaside-Platform through  
Seaside-Environment), I found no (non-test) senders of  
Stream>>#'position:' and only one sender of Stream>>#'position'. The  
single sender of #'position' was WAEncoder class>>#'initializeBMP' and  
the test for the size of the stream contents was trivially refactored  
to use #'size' instead.

There only remaining references were both added recently to test  
Stream for ANSI compatibility. Given that Seaside does not send these  
messages (as far as I've been able to determine), I wonder if we could  
create a new package, ANSI-Tests, to hold tests for platform behavior  
that is not needed by Seaside. Philosophically, I'd very much like to  
have all the tests pass. If there are tests that specifically point  
out failures in unnecessary functionality, it would be nice if they  
could be isolated and expected to fail.

Any suggestions?

James Foster

P.S. Apologies if this arrives twice. The first time I sent it was  
from an email address that is not subscribed to the list.