Certainly. At the moment you are probably 50% of the treeparse user base, so it needs to be fast enough for your use case :)

Hmm. Profiler.

I'm not 100% sure but maybe the fact that nearly all the composing parsers decompose the return value of sub-parsers, then recompose the return value, might be slowing it down? Maybe have parsers accept an optional return value argument, which 'return will fill in (instead of creating its own) might reduce significantly the memory consumption (assuming it's GC which is slowing it down)?

mockup:

  (def parser-function (remaining (o retval (list nil nil nil)))
    (....)
    (return parsed li actions retval))

  (def many-r (parser remaining acc act-acc (o retval (list nil nil nil)))
      (while (parse parser remaining retval)
        ; parsed
        (lconc acc (copy (car retval)))
        ; actions
        (lconc act-acc (copy (car:cdr:cdr retval)))
        (= remaining (car:cdr scratch)))
      (return (car acc) remaining (car act-acc) retval))

  (time (do ((many anything) (range 1 5000)) nil))

  (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)))

  (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 ^^

  (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))))

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

  (= *wiki-profiling-on nil)

Note that turning on profiling increases time by a factor of > 5. Don't use unless desperate.

Anyway a sample run - this page was rendered in about 800msec without profiling, with profiling it took about 5150msec:

  bold: 305
  bolded-text: 914
  nowiki-e: 31
  open-br: 305
  seq-r: 2681
  italicized-text: 793
  many-format: 4830
  plain-wiki-link: 841
  alt-r: 4555
  nowiki-text: 584
  nowiki: 184
  joined-wiki-link: 413
  ampersand-coded-text: 486
  ampersand-codes: 171
  italics: 128
  many-r: 4829
  formatting: 4616
  close-br: 39

    formatting               4616
    [-] alt-r                4555
     | bolded-text            914
     | plain-wiki-link        841
     | italicized-text        793
     | nowiki-text            584
     | ampersand-coded-text   486
     | joined-wiki-link       413

My test page has quite a bit of bolded text (for testing), so I suppose it's the reason why bolded-text is the highest. Hmm.

Anyway I'm thinking of adding the following parser to the top of the big 'alt structure in formatting:

  (= plain-text
    (pred [or (alphadig _) (whitec _) (in _ #\. #\,)] anything))

  (= formatting
    (alt
      plain-text
      ...))