On 01/08/07, Greg Meredith
Haskellians,
Though the actual metaphor in the monads-via-loops doesn't seem to fly with this audience, i like the spirit of the communication and the implicit challenge: find a pithy slogan that -- for a particular audience, like imperative programmers -- serves to uncover the essence of the notion. i can't really address that audience as my first real exposure to programming was scheme and i moved into concurrency and reflection after that and only ever used imperative languages as means to an end. That said, i think i found another metaphor that summarizes the notion for me. In the same way that the group axioms organize notions of symmetry, including addition, multiplication, reflections, translations, rotations, ... the monad(ic axioms) organize(s) notions of snapshot (return) and update (bind), including state, i/o, control, .... In short
group : symmetry :: monad : update
Best wishes,
--greg
Hello, I just wrote http://www.haskell.org/haskellwiki/Monads_as_computation after starting to reply to this thread and then getting sidetracked into writing a monad tutorial based on the approach I've been taking in the ad-hoc tutorials I've been giving on #haskell lately. :) It might be worth sifting through in order to determine an anthem for monads. Something along the lines of: "monads are just a specific kind of {embedded domain specific language, combinator library}" would work, provided that the person you're talking to knows what one of those is. :) I've found it very effective to explain those in general and then explain what a monad is in terms of them. I'm not certain that the article is completely finished. I'm a bit tired at the moment, and will probably return to polish the treatment some more when I'm more awake, but I think it's finished enough to usefully get the main ideas across. - Cale