I mentioned in my last post that I'd like to improve the performance of
fromList for all types exported by the unordered-containers package. Twan van Laarhoven beat me to it and his changes, together with some additional optimizations by me, made for quite a nice speed-up:
fromListWith should also see similar improvements.)
The improvements are in the unordered-containers-0.2.0.1 release.
I also plan to add additional functions e.g.
unfoldrM that will allow efficient bulk creation of maps and sets. For example,
unfoldrM will let you efficiently create a map (or set) from the content of a file.