This looks ok to me. The two instances do not unify, because
(c1 a1) does not unify with (c2 a2, c2 b2)
GHC is happy with it.
Simon
| -----Original Message-----
| From: Jonathon Bell [mailto:[EMAIL PROTECTED]]
| Sent: 16 April 2001 22:43
| To: '[EMAIL PROTECTED]'
| Subject: Possible bug?
|
|
| Hi chaps,
|
| Hugs (Feb 2001) fails to compile the following, complaining
| that the instances are not consistent with the dependencies:
|
| class Foo f a r | f a->r where
|
| foo::f->a->r
|
| instance Foo (a->r) (c a) (c r)
|
| instance Foo ((a,b)->r) (c a,c b)(c r)
|
|
| My intention is to overload the uncurried function foo for
| based on both its arity and the kind of tuple it is passed.
| Could you please explain what i am doing wrong here?
|
| Thank you so much,
|
| _______________________________
| Jonathon Bell [EMAIL PROTECTED]
| MathSoft, Inc. www.mathsoft.com
| 101 Main St, Cambridge, MA 02142
| (617) 577-1017 x745
|
|
| _______________________________________________
| Hugs-Bugs mailing list
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