Hi, I am pleased to announce HLint version 1.2. HLint is a lint-like tool for Haskell that detects and suggests improvements for your code. HLint is compatible with most GHC extensions, and supports a wide variety of suggestions, and can be extended with additional user suggestions. To install: cabal update && cabal install hlint Web page: http://www-users.cs.york.ac.uk/~ndm/hlint/ Biggest new feature: List recursion suggestions. For example, running HLint over the GHC compiler now suggests things such as: Example.hs:3:1: Warning: Use foldr Found: seqList [] b = b seqList (x : xs) b = x `seq` seqList xs b Why not: seqList xs b = foldr seq b xs Example.hs:6:1: Warning: Use foldr Found: seqIds [] = () seqIds (id : ids) = seqId id `seq` seqIds ids Why not: seqIds ids = foldr (seq . seqId) () ids Example.hs:13:1: Warning: Use foldl Found: rev_app [] xs = xs rev_app (y : ys) xs = rev_app ys (y : xs) Why not: rev_app ys xs = foldl (flip (:)) xs ys HLint will automatically detect if you should have used a map, a foldr or a foldl and suggest how to change your code. In the GHC, darcs and Hoogle code bases there are no obvious map-like functions, which is a good sign :-) Changes from last time: * More GHC extensions supported - including record wild cards and fixes to a number of existing extensions. These changes are thanks to Niklas and the haskell-src-exts package. * Many infix operators are now correctly associated with the right priority. * All hints are now ignored, warnings or errors. Hopefully this should make it clearer what hints are most important. As part of this, the format for defining ignore files has changed completely - see the manual for the new format. * Lots of new hints have been added - many from users of HLint. * Many bugs have been fixed. Can any follow-up discussions please be directed to haskell-cafe@. All comments, questions, bug reports are welcome! Neil