A rudimentary implementation of first species counterpoint that can generate a contrapuntal voice to a given cantus firmus.
Score and MIDI out is provided by Lilypond. Make sure that you have the application installed in /Applications/.
Enter the cantus firmus in my-cantus.asp. To generate all melodies, and output each as a PDF and MIDI file:
clingo 0 compose.lp cantus-firmi/my-cantus.lp species-one.lp
To generate N melodies:
clingo N compose.lp cantus-firmus.lp species-one.lp
You may find Timidity for playback and conversion.