On Mon, 24 Nov 2008 11:05:29 +0100 Ralf Hemmecke wrote:
> ...
> But CoercibleFrom and RetractableTo should be just one category.
> ...

Yes, I agree. In fact I would go further. Because RetractableTo(S)
includes 'coerce:S -> %' there may be some cases where the current use
of 'CoercibleTo' is inadequate.

I think that 'CoercibleTo' should be eliminated. In all domains A in
which the category CoercibleTo(B) occurs, it should be removed and
RetractableTo(A) added to the domain B (if not already present). All
occurrences of

   if A has CoercibleTo(B) then ...

should be replaced with

  if B has RetractableTo(A) then ...

In a few cases this might mean providing code for missing retractions.

Regards,
Bill Page.

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