On Sun, 2008-11-09 at 19:18 +0000, Andrew Coppin wrote:
Derek Elkins wrote:
As far as I can tell, no one actually uses parallel list comprehensions. With any luck, the same will be true for generalized list comprehensions.
Generalised? Heck, I don't use list comprehension at all! :-P
Perhaps you should! :-) When I first started with Haskell I kind of had the idea that list comprehensions were just for beginners and that 'real' hackers used just concatMaps and filters. A couple years later I 'rediscovered' list comprehensions and I now use them frequently. There are many cases in real programs where simple and not-so-simple list comprehensions are the clearest way of expressing the solution. In particular the easy support for refutable pattern matching in the generators allows some succinct and clear code. Just a random example out of Cabal: warn verbosity $ "This package indirectly depends on multiple versions of the same " ++ "package. This is highly likely to cause a compile failure.\n" ++ unlines [ "package " ++ display pkg ++ " requires " ++ display (PackageIdentifier name ver) | (name, uses) <- inconsistencies , (pkg, ver) <- uses ] Pretty concise and clear I think. Duncan