Re: [Haskell-cafe] Before

Dan Piponi wrote:

On 7/2/07, Andrew Coppin wrote:

...

What were monads like before they became a Haskell language construct?

Is Haskell's idea of a "monad" actually anywhere close to the original mathematical formalism?

It's as close to a mathematician's notion of a monad as Haskell's types and functions are to the objects and arrows of category theory.

Right. So it's a pretty close correspondence.

http://en.wikipedia.org/wiki/Monad_%28category_theory%29

"Monads are important in the theory of pairs of adjoint functors. They can be viewed as monoid objects in a category of endofunctors (hence the name) and they generalize closure operators on posets to arbitrary categories." *cried softly in the corner* I knew asking questions about theoretical mathematics probably wasn't a good idea...

Knowing that you were about to ask this question I told my past self by tachyon express and wrote up on it this weekend: http://sigfpe.blogspot.com/2007/06/monads-from-algebra-and-the-gray-code.htm...

Heh. *I* would have just told my past self next week's lottery numbers...