On Sat, Jul 07, 2007 at 06:49:25PM +0100, Andrew Coppin wrote:
Dave Bayer wrote:
I was beginning to accept that I might die before clearing my pipeline of research projects I want to code up.
...so it's *not* just me!
Haskell has given me new hope.
Indeed. ;-)
Today I hve implemented encoders and decoders for RLE, MTF, Fibonacci codes, and LZW. Next on my list is BWT, Huffman codes and arithmetic coding. (That last is *very* hard though...)
You should look at Jeremy Gibbons' paper "Arithmetic coding with folds and unfolds". www.comlab.ox.ac.uk/oucl/work/jeremy.gibbons/publications/arith.pdf For your more general parsing troubles, have you considered making you lower level parsers copy the rest of the underlying input stream into each token they produce? After that transformation a simple string might look something like [(c,rest) | (c:rest) <- init (tails "Some characters of input")]. Brandon