30 Dec
2009
30 Dec
'09
9:05 p.m.
Excerpts from Joe Van Dyk's message of Wed Dec 30 20:49:12 -0500 2009:
What's the appropriate way to write this in Haskell?
Hi Joe, The Ticker class is an example of stateful computation, which we try to avoid in Haskell. What are you really trying to do? * If you a number, and you want to add to it, (+1) works plenty well. * If you are going to be making ticks, but you don't care about reading the ticks until the end of the computation, the Writer monad is of interest. * If you need to update the tick count and read it, the State monad is a good bet. * If you're interested in curiosities from imperative land, STRef, IORef and other similar creatures may be helpful. Cheers, Edward