[olivierduval]

Actually, music is a living art... so for example some blues chords progression would be "impossible" in classical music. And some "free jazz" or multimodal progression wouldn't work in blues

The point is: a computer is good to analyse something following a fixed set of rules, but not so good to analyse something that work by "breaking rules", like art. It's quite "easy" to write some program for classical music, or blues, or rock, or any specific music style... but it will hardly work for a different music style because the progression and interpretation of chords will be different