the amazing (and amazingly old) filladapt mode

[Adam Doppelt <amd@gurge.com>]

Does anyone else use filladapt mode for filling paragraphs? This thing
is great. It modifies fill-paragraph to handle a wide variety of line
prefixes. See examples below. It's hosted by the author here:

http://www.wonderworks.com/download/filladapt.el

filladapt hasn't been updated since 1998 but miraculously continues to
work, albeit with a few warts. I also get the sense that it's not a
very good citizen since it overwrites some core functions rather than
advising them.

I'm wondering if some kind soul would like to modernize it and add it
to elpa, or possibly bring the equivalent functionality to
adaptive-fill-mode. Unfortunately my elisp skills are quite weak,
otherwise I'd attempt it myself. I think a lot of people would
appreciate the effort.

Examples from filladapt.el:

1. xxxxx
   xxxxx

2.1.3  xxxxx xx x xx x
       xxx

a. xxxxxx xx
   xxx xxx

1) xxxx x xx x xx   or   (1) xx xx x x xx xx
   xx xx xxxx                xxx xx x x xx x

a) xxxx x xx x xx   or   (a) xx xx x x xx xx
   xx xx xxxx                xxx xx x x xx x

2a. xx x xxx x x xxx
    xxx xx x xx x

1a) xxxx x xx x xx   or   (1a) xx xx x x xx xx
    xx xx xxxx                 xxx xx x x xx x

-  xx xxx xxxx   or   *  xx xx x xxx xxx
   xxx xx xx             x xxx x xx x x x

o  xx xxx xxxx xx x xx xxx x xxx xx x xxx
   xxx xx xx

Thanks,

Adam