[clean-list] a local function typing question in function composition

[Arjen van Weelden]

The type you specified would be correct except that, due to the scope of 
type variables, `a -> c' does not match the other `a -> c'.

According to the lexical scope rules of Clean, the type variables 'a' 
and 'c' in the type for `h' are different from the 'a' and 'c' in the 
type for `(oo)'. If you let the type checker derive the type for `h' 
automatically it does the right thing. However, by specifying a 
different `a' and `c', the types no longer match.

kind regards,
	Arjen

Jigang Sun wrote:
> What I want to know the type of composition function h.
> Cheers.
> Jigang
> 
> -----Original Message-----
> From: TK <0000tk at gmail.com>
> To: "Jigang Sun" <Jigang.Sun at student.paisley.ac.uk>
> Date: Fri, 6 Apr 2007 22:05:58 +0300
> Subject: Re: [clean-list] a local function typing question in function composition
> 
> Have you tried to remove the type of function h?
> 
> 
> ( oo ) infixr 9 :: ( b -> c ) ( a -> b ) -> ( a -> c )
> ( oo ) g f = h
> where
> //    h :: a -> c
>     h x = g ( f x )
> 
> 
> 
> 
> 
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