On 2 November 2010 04:18, Richard O'Keefe
SML/NJ MLton 0.899 0.244 boring old plain list 5.481 1.244 build a "raum" using raums 8.186 1.380 build a raum then convert it to a list 12.581 4.449 build a "dlist" using dlists 16.209 5.096 build a dlist then convert it to a list
Times were measured on an Intel Core 2 Duo Mac running Mac OS X 10.6.4, SSML/NJ v110.70 [built: Wed Jun 17 16:24:00 2009] MLton MLTONVERSION (built Mon Jun 15 11:10:01 CDT 2009 on fenrir.uchicago.edu)
Building a list using dlists is 16 (SML/NJ) or 20 (MLton) times slower than using a plain list.
Caveat: because raums handle reverse in O(1) time as well as concatenation, for a fair comparison I made dlists do the same,
Och, adding reverse or even head and tail to a Dlist / Hughes list seems out of spirit with the idea - build as a Hughes list (enjoying cheap concat) - convert to a list and manipulate thereafter. I know the version on Hackage has head, tail, fmap etc. their existence is one of the reasons I avoid it and roll my own. Interestingly what was the test doing for boring old plain list to do so well? More than just cons I hope. Best wishes Stephen