Hugs will happily accept definitions such as:
(f `cross` g) (x, y) = (f x , g y)
while ghc gives
parse error on input: "cross"
It is not that ghc doesn't like any definition with `` on the left, as
x `op` y = x + y is fine, it just seems to be cases with brackets.
It is not entirely clear from
Hugs incorrectly allows declarations such as:
(f `cross` g) (x, y) = (f x , g y)
and
(f.g) x = f (g x)
because it parses patterns as expressions and then weeds out the things
that don't make any sense.
GHC does a better job of implementing Haskell 1.4 syntax/semantics in this
regard.
