[Haskell-cafe] Re: Type question in instance of a class

Janis Voigtlaender voigt at tcs.inf.tu-dresden.de
Sat Nov 22 08:24:33 EST 2008


Peter Hercek wrote:
> But Haskell with Control.Exception extension has more values
>   of all types since they can be thrown and later caught and
>   investigated at that place.
> 
> Maybe the last sentence of section 2.1 (_|_ Bottom) of
>   "Haskell/Denotational semantics" should be clarified better.
> 
> http://en.wikibooks.org/wiki/Haskell/Denotational_semantics#.E2.8A.A5_Bottom 
> 
> 
> So when trying to use Curry-Howard isomorphism for something
>   in Haskell, one sould be pretty carefull what features of are
>   being used.

Definitely. And that surfaces even in quite innocently looking programs
and statements about them. The introductory example of the following
technical report may be amusing in that respect:

http://wwwtcs.inf.tu-dresden.de/~voigt/TUD-FI08-08.pdf

Ciao, Janis.

-- 
Dr. Janis Voigtlaender
http://wwwtcs.inf.tu-dresden.de/~voigt/
mailto:voigt at tcs.inf.tu-dresden.de




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