[Haskell-cafe] Re: the Haskell notion of class vis-a-vis universal algebra?

[Achim Schneider]

"Galchin, Vasili" <vigalchin at gmail.com> wrote:

> Hello,
> 
>        What is the relationship of a Haskell class to universal
> algebra? (a refresher ...
> http://en.wikipedia.org/wiki/Universal_algebra) ... it seems that all
> types that belong to a class are models? E.g. all "monads" have to
> satisfy the "monad laws" stated in the Monad class, i.e. equational
> axioms!
> 
Nah, Haskell isn't that strong, it only ensures type integrity, not the
laws themselves. Doing that isn't decidable in the genaral case as
it'd require source analysis, at least with the current state of types.

I better not attempt to answer the rest as I'm way to far off my home
turf. Ask Jonathan.


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