Dan Piponi
I have a situation where I have a bunch of lists and I'll frequently be making new lists from the old ones by applying map and filter.
(While keeping the old ones around, I presume?) One option (or source of inspiration) might be lazy bytestrings, which are stored as lists of chunks, each chunk being a strict bytesting. A strict bytestring is a pointer to an array, an offset and a length. Thus, your initial lists could be contigous arrays, derivied list would be a sequence of chunks, each chunk either containing substrings of the original list or modified elements. So if f is id for positions 0..3 and 9..10, you could have: orig = Chunk (PS v 0 10) Empty map' f orig => Chunk (PS v 0 3) (Chunk (PS w 0 4) (Chunk (PS v 9 10) Empty)) Possibly vector generalizes this to datatypes beyond Word8, I haven't looked. -k -- If I haven't seen further, it is by standing in the footprints of giants