I've noticed this question asked here 6 or 7 years ago but have not been able to find a solution. I want to use a chord symbol for an open interval (G D) with no third. I have tried using g1^3 but the symbol still appears as "G." I'd like it to say "G (no3)." I tried to accomplish it using this snippet from the reference manual:
% modify maj9 and 6(add9) % Exception music is chords with markups chExceptionMusic = { <g d>1-\markup { \super "(no3)" } }
% Convert music to list and prepend to existing exceptions.
chExceptions = #( append ( sequential-music-to-chord-exceptions chExceptionMusic #t) ignatzekExceptions)