#(define (mark-one-ignatzek-chord-names in-pitches bass inversion context)
(markup #:line ("1. " (ignatzek-chord-names in-pitches bass
inversion context))))
#(define (mark-two-ignatzek-chord-names in-pitches bass inversion context)
(markup #:line ("2. " (ignatzek-chord-names in-pitches bass
inversion context))))
NumOne = { \set chordNameFunction = #mark-one-ignatzek-chord-names }
NumTwo = { \set chordNameFunction = #mark-two-ignatzek-chord-names }
NoNum = { \unset chordNameFunction }
and then
\NumOne c:7 \NoNum
or
\NumTwo a:7 \noNum