Re: MPC dunce question.

1998-02-04 Thread Alex Ferguson
Simon, thanks for the explanation, that makes a bit more sense now. So the situation is that a relaxation of this rule is possible, it's just a matter of whether this would ever be any use to anyone, and indeed worth the extra pain of all those (additional) Overlapping Instance!, and Ambiguity! e

Re: MPC dunce question.

1998-02-04 Thread Simon L Peyton Jones
> While hacking around with MPCs, trying to define a variant of the > Collection class, mutated to suit my own fiendish ends, I ran into > this: > > Intervals.hs:345: > Class type variable `e' does not appear in method signature > union2 :: s -> s -> s > > What's the significance o

MPC dunce question.

1998-02-03 Thread Alex Ferguson
While hacking around with MPCs, trying to define a variant of the Collection class, mutated to suit my own fiendish ends, I ran into this: Intervals.hs:345: Class type variable `e' does not appear in method signature union2 :: s -> s -> s What's the significance of this restriction?