[Haskell-cafe] All equations must have the same arity - why?

[ajb at spamcop.net]

G'day all.

Quoting Conal Elliott <conal at conal.net>:

> That eta-expansion desugaring would lose sharing.  Offhand, I don't know of
> a desugaring that would do the trick and preserve sharing.  Any ideas?

How about this?

f = let body = sort . nub
        in \xs -> case xs of
            [] -> [1]
            (_:_) -> body

I suspect we're well out of the territory of mere "desugaring" here,
though.

Cheers,
Andrew Bromage