[Seaside-dev] Seaside-Core-jok.482.mcz

[Julian Fitzell]

I think honestly you could just add an isEmpty check or something...
but whatever you think it cleaner is fine.

On Fri, Feb 20, 2009 at 5:56 PM, John O'Keefe
<wembley.instantiations at gmail.com> wrote:
> Julian -
>
> OK, first the explanation of the compatibility issue:
>
> VA Smalltalk implements both class-based and instance-based
> exceptions.   Internally we still mostly use instance-based and the
> class-based exceptions are mapped one-to-one with existing (or new)
> instance based exceptions).
>
> However, there are still some subtle differences.  One of these is the
> effect of falling off the end of a handler block (a condition that is
> not explicitly described in the ANSI spec).  For class-based
> exceptions, the code will resume if it was a resumable exception,
> otherwise it will return; for instance-based exceptions it always does
> a resume.  To maintain compatibility with existing usage, I am very
> reluctant to change this behavior for instance-based exceptions.
>
> Dictionary>>#at: signals a non-resumeable instance-based exception
> (another behavior I can't change).  So, on VA Smalltalk, wrapping
> Dictionary>>#at: in an exception handler with a handler block that
> falls off the end tries to resume and halts with the debugger up (not
> good!).
>
> I obviously misunderstood the total ramifications of the exception
> handler in this method.  I think the best thing for me to do is leave
> the change in the first line of code, and then put everything back
> into an #on:do: with a handler block that does an explicit return.
>
> John O'Keefe [|], Principal Smalltalk Architect, Instantiations Inc.
>
>
>
> On Fri, Feb 20, 2009 at 11:14 AM, Julian Fitzell <jfitzell at gmail.com> wrote:
>> John,
>>
>> I'm the error handler there must not have been there just to deal with
>> #at: failing (though obviously it is handling that too) but also to
>> handle the case where keyString is a collection (not a string) and is
>> empty. I'm just surmising by looking at the code because it would not
>> have made sense for someone to write it that way otherwise (clearly
>> #at:ifAbsent: would be better for the #at: case).
>>
>> I don't quite understand the compatibility issue you mention. I
>> certainly don't care if the code is rewritten without the #on:do: but
>> it seems like your version is not at robust as the previous version
>> was.
>>
>> Julian
>>
>>>Seaside-Core-jok.482.mcz
>>>from Seaside 2.9 by John O'Keefe <john_okeefe at instantiations.com>
>>>Since a WARequest understands at:ifAbsent:, use it.
>>>This fixes a VA Smalltalk portability issue -- Dictionary>>#at:
>>>signals an instance-based exception when the key cannot be found and that exception cannot be handled by an empty #on:do: handler block.
>> _______________________________________________
>> seaside-dev mailing list
>> seaside-dev at lists.squeakfoundation.org
>> http://lists.squeakfoundation.org/mailman/listinfo/seaside-dev
>>
> _______________________________________________
> seaside-dev mailing list
> seaside-dev at lists.squeakfoundation.org
> http://lists.squeakfoundation.org/mailman/listinfo/seaside-dev
>