In the manual is says"" Once the arrangement is finished, it can be exported to usual LilyPond source:flute = {...} clar = {...}
From arrangerDoc.pdf : export-instruments syntax (export-instruments instruments filename #:optional overwrite?) So something like (export-instruments '(flute clar...) "exported-file.ly" #f)should produce in the current directory, a file called "exported-file.ly", with the definition of flute and clar.
Is this the case ? It's a problem if not ! -- Gilles
