On Fri, Nov 14, 2008 at 1:00 PM, Mr. SpOOn <[EMAIL PROTECTED]> 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
I don't know if this is any better, but you could represent a chord formula as a 15-tuple consisting of (-, n, b, #) for instance, so maj = (n, -, n, -, n, -, -, -, -, -, -, -, -, -, -) min = (n, -, b, -, n, -, -, -, -, -, -, -, -, -, -) #9 = (n, -, n, -, n, -, n, -, #, -, -, -, -, -, -) and just have a lookup table. (Or a 7-tuple and do mod arithmetic to get the extensions) Then you could remove (well, I suppose with a tuple it would be build a new one, or you could use a list?) anything with "no." Just a thought...I don't ever do anything very complicated in Python though so I don't know if that's Pythonic either ;) -dan -- http://mail.python.org/mailman/listinfo/python-list
