n+k patterns

[Simon Peyton-Jones]

| Hugs "demands Integral" because that's what it was told to do=20
| to follow the report.  So in that sense, yes, the code=20
| depends on having only one class.  But it would be easy for=20
| someone to change that.
|=20
| Then again, if we're following the rules of minimal change=20
| for Haskell 98, then I wouldn't have thought this was up for=20
| grabs. (I'm thinking, for example, of the unnecessary "same=20
| context" restriction on mutually recursive binding groups,=20
| which has more practical impact, is very clearly a "bug", and=20
| has not (AFAIK) been fixed in Haskell 98.  Then there's David=20
| Wakeling's generalized gap proposal, and ...)

That is a fair point, and is exactly the reason I bother the Haskell
list with
these proposals rather than simply executing them.   This is an unforced
change, as you point out, but in fact GHC and NHC currently do one
thing, and
Hugs does another (i.e. follows the spec!).  So some of us have to
change
our implementations.=20

It clearly isn't a big deal, because no one has ever reported this
as a practical problem.

Other things being equal, it would be better to make the spec make=20
as much sense as possible; hence my proposal.  But if it's really hard
to change Hugs, maybe we should leave the spec and change GHC and
nhc.   But you say it would be easy.=20

I agree it's a moot point.  I lean towards making the change,
but I'm willing to be persuaded.

Simon