Not lazy/smart enough

[Alastair David Reid]

>>>>> "Sohrab" == Sohrab Saran <sohrabsaran@hotmail.com> writes:

> If at the Hugs interpreter prompt I type:
> 3/4 == 3/4
> ...I get "True"
> If I now type:
> 3/0 == 3/0
> ...I should get "True" but I get a divide-by-zero error
> instead. Anyone ready to fix this, or should I fix this myself?

I don't believe this is a bug.

Suppose we adopt your proposal, I think we'd also want to add the 
following equalities too:
  
  1.  f 3 == f 3  = True
  
  2.  f 3 == g 3  = True  where g x = f x
  
  3.  f 3 == g 3  = True  where g x = x / 0; f x = x / 0
  
  4.  f 3 == g 3  = True  where g is semantically equivalent to f
  
The problem with this is that it's hard to say why we'd accept 1-3 but
not accept 4 and accepting 4 requires us to solve the halting problem.

-- 
Alastair Reid        reid@cs.utah.edu        http://www.cs.utah.edu/~reid/