An extra accidental-style might be needed

[Valentin Villenave]

Hello everyone,

most of the composers I know use a typographical convention I can't
get LilyPond to automatically apply:

--the first accidental in a bar is printed (like in 'default style)
--if a note with an accidental is immediately repeated in the same bar
(same pitch, same octave), the accidental is not printed (like in
'default style)
--if the same note occurs later in the bar, the accidental is printed
again (like in 'forget style)
--if the same note gets natural, even at a different octave, a natural
sign is printed (like in 'modern style)
--sometimes, cautionnary naturals signs can even be printed in the
immediately following bar, without parentheses or whatever (which can
be obtained in Lily by setting the "laziness" property) --just in case
the musician would forget there isn't any accidental anymore...

(I know, it looks a bit weird, but I can tell you many scores are
printed this way nowadays: you can, for instance, find some examples
of this practice in most of recent French Salabert scores.)

As it seems to have become a very popular way (and it makes indeed
atonal music quite easier to read, for both composers and musicians),
maybe this could be added to LilyPond.
There again, I'd definitely be glad to sponsor it --but what looks
complicated to me will maybe get solved in one second by one of you
guys...

Regards,
Valentin