Arc Forumnew | comments | leaders | submitlogin
1 point by raymyers 5866 days ago | link | parent

I tried taking out actions for the heck of it. Removing them yields roughly a 30% speed increase on this benchmark:

  (time (do ((many anything) (range 1 5000)) nil))
Using the following method, we can keep actions as a feature but still get the 30% speedup when we don't use them.

  (def many (parser)
    "Parser is repeated zero or more times."
    (fn (remaining) (many-r parser remaining (tconc-new) nil)))

  (def many-r (parser li acc act-acc)
    (iflet (parsed remaining actions) (parse parser li)
           (many-r parser remaining
                   (lconc acc (copy parsed))
                   (if actions (join act-acc actions) act-acc))
           (return (car acc) li act-acc)))
Not bad, but still not as fast as we'd want for processing wiki formatting on the fly...

ed: Yes. act-acc, not (car act-acc).



1 point by almkglor 5866 days ago | link

Hmm. If you remove 'actions, how about also trying to use just a single 'cons cell:

  (iflet (parsed . remaining) (parse parser remaining)
    ...)

  (def return (parsed remaining)
    (cons parsed remaining))
?

If the speed increase is that large on that testbench, it might very well be due to garbage collection.

This might be an interesting page for our problem here ^^

http://www.valuedlessons.com/2008/03/why-are-my-monads-so-sl...

-----

1 point by raymyers 5866 days ago | link

Tried changing the list to a single cons cell. I did not see any additional performance boost.

-----

1 point by almkglor 5866 days ago | link

  (def many-r (parser li acc act-acc)
    (iflet (parsed remaining actions) (parse parser li)
           (many-r parser remaining
                   (lconc acc (copy parsed))
                   (if actions (join act-acc actions) act-acc))
           (return (car acc) li (car act-acc))))
s/(car act-acc)/act-acc maybe?

Personally I don't mind losing 'actions, it does seem that 'filt would be better ^^.

-----

1 point by almkglor 5866 days ago | link

I tested this on my 8-paragraph 5000-char lorem ipsum page, and the run dropped down to about 3400msec (from 3800 msec).

Hmm. Not sure where the slow down is now ^^

I've tried my "retval" suggestion and it's actually slower, not faster. So much for not creating new objects T.T;

-----