Recursive Function for finding complementary set of notes in Chord/Scale relationship

[JulioHerrlein]

Hey, people !

 

I´m doing a function to extract the complementary set of notes.

For example:

 

1) Specify a set of notes, like a chord, Dm7

 

(setf note-list '(d5 f5 a5 c6))

 

Specify a tonality, like Cmajor or D dorian (same notes)

(expand-tonality '(c5 major))

 

Now, I want a function that gives me all the other available notes from the mode, except the chord tones (the first set of notes).

 

So, this function gives me exactly what I need (for ONE tonality at a time and ONE chord at a time):

 

(let ((rem (expand-tonality '(c5 major)))
      (super (ambitus '(c5 b5) note-list)))
  (loop for i in super
    do (setf rem (remove i rem))
    finally (return rem)))

 

Ok, this give me the right result, I.E., the complementary set of notes of C major in relation to Dm7

=> (e5 g5 b5)

 

The question is simple:

 

How can I do it for a list with many tonalities and many chords. How to do this recursively in nested lists, like

 

(setf note-list '((d5 f5 a5 c6)(eb4 gb4 bb4 db4)(fs4 as4 cs4)))

 

to sucessive tonalities, like:

(expand-tonality '((c5 major) (db4 major) (gb4 major)))

 

Since this WON´T work

 

(let ((rem (ambitus '(c5 b5) (expand-tonality '((c5 major) (db5 major) (gb5 major)))))
      (super (ambitus '(c5 b5) '((d5 f5 a5 c6)(eb4 gb4 bb4 db4)(fs4 as4 cs4)))))
  (loop for i in super
    do (setf rem (remove i rem))
    finally (return rem)))

 

The expected result, if the above worked would be:

 

 ((e5 g5 b5)  (f5 ab5 c5) (gs4 cb5 ds5))

 

Thanks in advance !!

 

Best !

Julio

[opmo]

Loop in the loop:

 

(let ((rem (ambitus '(c5 b5) (expand-tonality '((c5 major) (db5 major) (gb5 major)))))
      (super (ambitus '(c5 b5) '((d5 f5 a5 c6) (eb4 gb4 bb4 db4) (fs4 as4 cs4)))))
  (loop for s in super
    for r in rem
    collect (loop for i in s
              do (setf r (remove i r))
              finally (return r))))

[JulioHerrlein]

Thanks, Janusz

 

This could implemented as a native function, like

 

FILTER-SET

 

A general function to filter sets out of sets.

 

Best,

Julio