Well, modifying linebreak_filter would be a good idea indeed :)Otherwise, you could put the clef in a \cleaders: \newbox\clefbox \setbox\clefbox=\hbox{<clef>} \def\clef{\cleaders\copy\clefbox\hskip\wd\clefbox} note ... note ... \clef ... note ... note then it will automatically disappear at the beginning of a line. Of course the above code is cumbersome, all the more as<clef> won’t interact with surrounding glyphs if that must happen (e.g. spacing). So you could use the symbol as usual, and then in pre_linebreak_filter (i.e. after kerning, ligaturing, etc., have occurred, i.e. after the glyph has been processed) turn the sublist made of that glyph and associated material into an hlist, and create a leader node pointing to it (really, a glue with a “leader” field pointing to the created box). I guess it’ll work, and it’s much simpler than tinkering with the algorithm (all the more as the Lua version is much slower than the TeX version, if I remember correctly a recent paper by Hans).
Hmmm, this opens some interesting perspectives! I have to say I would *never* have thought to something like this... I've never used cleaders but I'll learn...
If between two book readings you ever have a little time to help... ;) Thank you very much, -- Elie
