On Jun 18, 12:59 pm, "Edward Z. Yang"
... I would still prefer Haskel for a system intended for production; with the pain of making sure you've handled all of the possible constructors for the data you're operating on, you also have a pretty good assurance that you haven't forgotten anything stupid.
Absolutely. You suddenly feel naked when a working dynamic system must pass assurances, and all those unit tests are just busywork of the script kiddies trying to make it look reliable. :) Nothing like a good static type system to be able to trust the thing more. However, some things are hard to catch even with strict typing. Here's an example from my current program: dstarts = M.fromList $ map dayUsers (groupBy ((==) `on` snd) dranges) This was a bug. dranges is a [(User, (Int,Int))], and I needed the first int of the pair, not the whole pair. But groupBy would take either. I had to identify it and replace by dstarts = M.fromList $ map dayUsers (groupBy ((==) `on` fst . snd) dranges) -- which feel almost like Clojure's easy tweaking. Both things type check unless I add the type signature for dstarts. But where to add them is not clear from the get-go, and you want to use inference where you think what you mean is clear... which sometimes is not. -- Alexy