I'm working on basic support (very basic) for bidi text and
I'm facing a problem with \list because it relies on \parshape.
I copy a message I sent to the luatex list:

Well, after thinking a little more about this I'm not so
sure. The problem is \parshape is used for two different
purposes: (a) fancy paragraphs (a heart, the map of The
Netherlands, wrapping some text around a figure, etc.);
(b) an alternative to \left/rightskip and \parindent.
While mirroring the latter makes sense, mirroring
The Netherlands seems a bit odd. I wonder if an
alternative could be \parshape dir XXX, like boxes.

I'd like not to touch the core at all (until now I've
managed to do it), and on the other hand many packages
emulate what LaTeX does. Suggestions?