On Thu, Dec 22, 2005 at 01:53:34PM -0800, Greg Woodhouse wrote:
The trick, though, is that objects are stateful things. If you want to program a binary search tree, then insertion ought to return an entirely new tree, just as if objects were all immutable, and operations on those objects simply creaqte new objects exactly like the existing ones (except for the one change). I've thought about trying to model this using monads and actions, but I'm not sure that's the best approach.
Use lexical closures. Initialize the state, variables, threads, etc, and then return (= expose) only the "methods", ie. monadic actions. Use the fact that both functions and IO actions are abstract (opaque?). Example: initObject = do var <- newVar let inc = do x <- readVar var writeVar var (x + 1) get = do readVar var return (inc, get) Best regards Tomasz -- I am searching for a programmer who is good at least in some of [Haskell, ML, C++, Linux, FreeBSD, math] for work in Warsaw, Poland