On Thu, 28 Feb 2002, Shawn P. Garbett wrote:
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Now after my earlier soap box tirade I'm trying to put my code where my mouth is. >>blush<< It's harder than I thought.
I've broken it down into a State Model of a light bulb. The goal, to find out just how much Haskell code does it take to change the state of a light bulb?
Here's a very crippled version. Is there an easy way to introduce state without changing the type of main???
Rhe IO monad IS a state monad without fetch and assign. (I'd hate to see it written in the traditional \s -> (s,v) sense, one fetch of the state gives you gigabytes of information that is on the computer, and then you'd have to include at least part of the 2^whatever bytes on all the other computers on the internet. Oh yeah, did i mention if you actually interface such a monad with reality, the state would have to include every bit of information with in the universe! Imagine, all of that dumped out, all with one single fetch!) :-) </Joke>
I've written a much more complex example, but I got into things like
main :: STT(IO)
using a monad transformer.
I did similar not to long ago on one of these lists, but it was more of an example of using a monad transformer for another goal.
So really, the big question is, must I use a monad transformer?
I'm confused as to what your goal is :) (plus I don't know where your previous post is). It doesn't seem like all that much code. Much of it is the definition of the state monad. Jay Cox