Joel Reymont <[EMAIL PROTECTED]> writes:
> Support I want to infer the type given an Op that looks like
> this (incomplete):
>
> data Op
> = Minus
> | Plus
> | Mul
> | LT
> | GT
>
> Is there a shorthand way of bunching Minus, Plus and Mul in
> a function guard since they all result in TyNum whereas the
> rest in TyBool?
>
> I really don't want several function clauses and neither do
> I want separate guards for every constructor.
Is there some reason why you don't want
data Op = Aop Aop | Bop Bop
data Aop = Minus | Plus | Mul
data Bop = LT | GT
or similar? I would agree that it's a shame one cannot just write
data Op = Aop (Minus | Plus | Mul) | Bop (LT | GT)
or even, given a somewhat different type system,
data Op = Aop | Bop
where Aop = Minus | Plus | Mul
Bop = LT | GT
but it would seem reasonable to reflect the different types
of the Ops in different types in their representations.
--
Jón Fairbairn [EMAIL PROTECTED]
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