Building musical chords starting from (a lot of) rules

[bvdp]

Mr.SpOOn wrote:
> Hi,
> I'm writing a method to create musical chords.
> 
> This method must follow a specific set of syntax rules. At least, this
> is my idea, but maybe there's a better way.
> Anyway, in the code I have class Chord which is a set.
> 
> The costrunction of a chord is based on a root note and a structure,
> so by default, giving just a note, it creates a major chord adding the
> third and fifth note.
> 
> So, in pseudo-code: Chord(C) -> [C, E, G]
> 
> And this is the base case. All the other rules must specify what kind
> of note to add or which one should be modified.
> 
> For example:   C min, means to add the third minor note: C Eb G
> 
> C 9 is a base chord plus a the ninth note, but this implies the
> presence of the seventh too, so it results in: C E G B D
> 
> But I can also say: C 9 no7, so it should just be: C E G D, without the seventh.
> 
> There are also more complex rules. For the eleventh, for example, it
> should add also the ninth and seventh note. In the normal case it adds
> their major version, but I can specify to add an augmented nine, so
> this modification must have precedence over the base case.
> 
> Anyway, I think I can use a chain of  if-clauses, one per rule and at
> the end remove the notes marked with "no". But this seems to me a very
> bad solution, not so pythonic. Before I proceed for this way, do you
> have any suggestion? Hope the problem is not too complicated.
> 
> Thanks,
> Carlo

Have a look at my program MMA which does just what I think you want. 
Well, probably for different purposes, but same end result with the 
chords. All table based, BTW.    http://www.mellowood.ca/mma