On Fri, Dec 22, 2006 at 06:16:03PM +0100, Joachim Durchholz wrote:
* Forcing the expressions that get written out means that I cannot use lazy evaluation freely. In particular, if some library code returns a data structure that contains a lazy-infinite subexpression, serializing it would not terminate, and I'd have little chance of fixing that.
I fear that you may not have a good intuition about laziness and how it is used in practical programming at this moment. Why not try and see if there really is a problem?
Now that the first serialization will destroy many of the advantages of laziness, I don't think I should try to wrestle with its disadvantages.
A common problem with laziness is the possibility of introducing space leaks. That's when the program accumulates a big thunk which, if forced, would reduce to a small and simple value. "Nobody" is interested in this value now, so it is kept in a lazy, space inefficient form. A classic example is a thunk like this (1+1+1+1+1+1+...) One solution to this problem is "deepSeq" - forcing full evaluation of a data structure. Naive serialisation performs this as a side-effect. What I want to tell is that the "problem" you see here could just as well be a *solution* to a different problem that you haven't considered yet - space leaks!
I'll move on to the alternatives - Alice ML and/or Clean. Both can serialize without forcing lazy subexpressions.
I am pretty sure that with those solutions you will meet other problems of the same caliber. What I propose is the following: keep Haskell as a possibility (with one discovered problem), consider problems with those other languages, then decide. There doesn't seem to be a perfect programming language.
This all said, I still don't think that Haskell or its execution environments are bad. They just don't fit my requirements, which are A) I want to get my feet wet with an FPL (seriously, this time), and B) I want to do a webserver application (I know the domain).
Haskell would play well with those requirements. I've created some web applications in it, and I was delighted with the things I learned in the process. I am starting to suspect that you have a third requirement you haven't told us about, like: C) I want to make profit ;-) Best regards Tomasz