todo.txt

Day 5:
 + SUtil: multi-replace. (Handle swapping)

Day 14:
 - Rapid: derive 'floating-bit' combinations using a recursive function &
   simple string building 

Day 17 part 2 (4D conway hyper-cubes):
 - Slow (260 ms) What sort of speed-up could be expected from symmetry? Only 4x?
 - Future utils:
     - handling >= 4D data
     - Combinatoric iterators (like python itertools)

Day 19 (parsing) - oh, so many ideas...
 - Learn: browse other interesting solutions
 - Perf:
    -- stop with all the array copying
    -- pre-process the rules?
 - Shortest: convert rule-text to an ANTLR grammar, generate a parser (or just tokenizer?)
 - Rapid: develop a reusable rule engine
 - Language: try one that makes the head|tail stuff more natural

 Day 21:
 - Another scenario for a rules engine (different logic, but can reuse process-of-elimination)

 Day 22:
 - Perf: Oow, the boxed integers & array shifting hurts! Fixed-size circular buffers?

 Day 25:
 - Perf: run 2 threads, first to complete wins.