[Hugs-users] :t / :f inconsistencies

[Ross Paterson]

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.