hi, In relation to my other message, I can contribute to this question. I think it is very important and useful to consider Strings as Sequences of Characters. And independently of the issue discussed elsewhere -- whether Characters should be a type or a class -- I am asking whether Sequences should be "linked list", that is functional stacks in Haskell. (Stacks because cons, head, tail are primitive.)
> 1. Today I spend a few hours trying to track down a memory leak. It > turns out I just didn't realize how much space a string takes up. > On my machine "replicate 5000000 'a'" will use 90MB of space! Of course, Packed Arrays will not really change this, but any implementation of Sequences, where ++ doesn't copy its first argument will. In Dessy's standard implementation the above will only use a few bytes... http://www.stud.tu-ilmenau.de/~robertw/dessy/fun/ > 2. They are extremely slow for most operations like writing to disk, > adding something to the end, concatenation, etc. Again, while PackedArrays can't do all of that better, there are a purely functional data structures, that can. I estimate that 99% of all uses of Sequence will work fine with the standard implementation or with Deques, found on the same page above. > 3. They make learning Haskell harder. Why is 'last' so much slower than 'head'? Why is 'head' not called 'first'? Why does 'but_last' (aka init) copy the list, but 'but_first' (aka tail) does not? The question is whether we want to teach abstraction or stack programming... Robert _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
