[Biococoa-dev] More on BCSymbolSets

Koen van der Drift kvddrift at earthlink.net
Sun Mar 6 16:54:49 EST 2005

On Mar 6, 2005, at 4:38 PM, Charles PARNOT wrote:

> Exactly my point. Koen, remember we need to give access to both a 
> generic class (BCSequence) and typed sequence classes (for John and 
> Alex... well, and potentially other users too!).

Thanks for the reminder :)

>> The more significant question is what should be returned.  Nil?  an 
>> error?
>> Use the default symbol set for that sequence type instead? Go 10.3 
>> only and
>> throw an exception?
>> My vote would be to fall back to the default if we get anything 
>> non-sensical
>> handed to us.
> I thought that too (see my code) but maybe another option is to use an 
> empty set, which means you get empty sequences no matter what you do. 
> The reason is you want something not ugly enough to generate runtime 
> errors (no nil, no exception), but still strong enough that the error 
> can not be missed (be it the user of the framework, or the user of the 
> BioCocoa-based app, doing something silly).

I also would prefer an empty sequence.

- Koen.

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