On Sun, Feb 05, 2006 at 02:09:39PM +0000, Neil Mitchell wrote:
I've always been confused when looking up symbols using :t and :f, never knowing if it should have brackets or not. I have finally figured out why I am confused:
Hugs> :t (^) (^) :: (Num a, Integral b) => a -> b -> a Hugs> :t ^ ERROR - Syntax error in expression (unexpected symbol "^") Hugs> :f ^ -- goes away and finds it Hugs> :f (^) ERROR - No current definition for name "(^)"
Essentially, :t wants brackets, :f doesn't.
I realise that in haskell ^ on its own is not a valid expression, and therefore that is a reason for :t not working on it. Perhaps a symbol on its own with no other stuff could be special cased for :t, since its certainly a valid answer to the question the user was asking.
I can't see any reason for :f not dropping brackets in all cases, since :f (,) and :f () doesn't work anyway (because of the way tuples are implicit in Hugs, it seems).
With these two changes, all of the above examples would work perfectly. I'm happy to have a go at hacking this up, provided its OK, and I haven't missed anything in my interpretation.
The current setup seems logical to me: :type <expr> :find <name> :info <name> I often use :t with more complex expressions, so it's no surprise. Changing it probably would do no harm, except for the extra complication; it just doesn't seem worth it to me.