31 Oct
2010
31 Oct
'10
11:05 p.m.
"Richard O'Keefe" <ok@cs.otago.ac.nz> writes:
There's a long-known technique in functional languages where [x1,...,xn] => \tail -> x1:...xn:tail xs ++ ys => f . g xs => f []
A correspondent mentioned to me that he couldn't find a reference to the idea (which I gather he had independently rediscovered). I know I've read about it somewhere. Can anyone provide a reference?
They're called difference lists: http://hackage.haskell.org/packages/archive/dlist/latest/doc/html/Data-DList... They allow O(1) snoc and append. I use them all the time! G -- Gregory Collins <greg@gregorycollins.net>