Re: dispatch

[David Bateman]

John W. Eaton wrote:

> I would like to merge the sparse-merge CVS branch with the main trunk
> soon.  The main thing holding up the merge is that the sparse code
> relies on the dispatch function from octave-forge, and I would prefer
> that the core Octave distribution not require functions from
> octave-forge.
>
> I like that the current implementation of dispatch only imposes the
> overhead of dispatching for functions that have been marked.  But when
> we implement Matlab-compatible classes, we will have to look for class
> methods for every function call (there can be a cache to speed
> lookups, but since people can add functions to @CLASS directories at
> runtime, I think we will still have to look in the filesystem to see
> if any new functions are available for a given class).
>
> Should we copy the dispatch function to Octave (as a short term
> solution that would allow the sparse code to be merged quickly) or
> take the time now to do more invasive surgery and add dispatch
> directly to the function lookup code in the core of Octave?
>
> Comments?
>
> Thanks,
>
> jwe
>
>
>  

My feelings are that as the wish list for version 3 included private 
directories and that classes are an extension of the same idea, and so 
not necessary all that much extra work, that version 3.0 should take the 
time to include a matlab compatiable version of classes. However it 
seems to me that dispatch in and of itself is valuable, even with 
classes, and so importing dispatch into octave seems logical and I'd 
suggest leaving it there even after classes are introduced. In that case 
why not go the way of the quick fix, and migrate the dispatching of the 
sparse functions to use classes as they are introduced.... It seems to 
me that classes/private directories are the last major item on the 3.0 
wishlist, so hopefully the wait won't be too long :-)

Regards
David



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David Bateman                                address@hidden
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