14 Jul 11:13 2007

## Re: Haskell & monads for newbies (was "Functional dependencies ***not*** part of the next Haskell standard?")

Alexis Hazell <dry.green.tea <at> gmail.com>

2007-07-14 09:13:43 GMT

2007-07-14 09:13:43 GMT

On Saturday 14 July 2007 05:21, Andrew Coppin wrote: > Still, while the concept is simple, it's hard to sum up in just a few > words what a monad "is". (Especially given that Haskell has so many > different ones - and they seem superficially to bear no resemblence to > each other.) Well, how about this as a starting point (from a post i wrote in my blog): "[In Haskell,] a monad simply seems to be a computational environment in which one can specify that certain types and methods of computation be performed, and in which the three monad laws are expected to hold." What do people think? With regards to the last phrase, i seem to recall that there are monads which nevertheless actually /don't/ follow all three monad laws? Alexis.