Negation

Simon Marlow marlowsd at gmail.com
Sat Feb 13 14:56:07 EST 2010


On 09/02/10 21:43, S. Doaitse Swierstra wrote:
> One we start discussing syntax again it might be a good occasion to
> reformulate/make more precise a few points.
>
> The following program is accepted by the Utrecht Haskell Compiler (here
> we took great effort to follow the report closely ;-} instead of
> spending our time on n+k patterns), but not by the GHC and Hugs.
>
> module Main where
>
> -- this is a (rather elaborate) definition of the number 1
> one = let x=1 in x
>
> -- this is a definition of the successor function using section notation
> increment = ( one + )
>
> -- but if we now unfold the definition of one we get a parser error in GHC
> increment' = ( let x=1 in x + )

Now that *is* an interesting example.  I had no idea we had a bug in 
that area. Seems to me that it ought to be possible to fix it by 
refactoring the grammar, but I haven't tried yet.

Are there any more of these that you know about?

Cheers,
	Simon


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