bag__remove vs bag__delete

[Fergus Henderson]

> > 	The question is whether it is better to rename bag__remove to
> > bag__delete (as it should be called), and make a new bag__remove, which is 
> > semidet.

Yes, that seems like the right approach.

(On a related note, we also need to fix the inconsistent argument
order of `subset' in the four set modules.)

-- 
Fergus Henderson <fjh at cs.mu.oz.au>   |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>   |  of excellence is a lethal habit"
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