Just a framework for musical expression in Common Lisp with a focus on music theory!

Totally building it from scratch, there's lots to do and a lot is missing/broken.

It currently uses SBCL timers for queuing real time midi events, so it's SBCL dependant.

See examples/nyan.lisp for an example of a song.

You can designate pitch classes with symbols:

'c'c♯'f♭'g♯♯♯

And actual notes with octaves as well:

'c5'a♭♭7

You can designate intervals with symbols:

'p5'maj72dim2 (doubly diminished second)

You can designate harmonies like this:

'ii'IVdom9'vmin42♯5

You can make a harmony like this:

(harmony 'I7/V) ;; => (D F♯ A C) (harmony 'IVmaj43) ;; => (C E F A)

You can get a scale like this:

(scale (key 'g-phrygian)) ;; => (G A♭ B♭ C D E♭ F)

You can designate scale degrees with either numbers, names or solfège syllables:

'(do re 3 4 dominant submediant)

You can realize scale degrees and pitch class like this:

(realize '(do re 34 dominant submediant)) ;; => (C4 E4 G4 F4 B4 A4 B4 G2)

You can also nest them:

(realize '(do re mi (fa sol la) ti do)) ;; => (C4 D4 E4 (F4 G4 A4) B4 C5)

And indicate octave displacements and rests like this:

(realize '(mi fa > mi fa > mi r <<<< re r)) ;; => (E4 F4 E5 F5 E6 R D2 R)

You can realize harmonic progressions in a simple way like this:

(realize (harmony '(I IV64 V43 I6))) ;; => ((C4 E4 G4) (C4 F4 A4) (D4 F4 G4 B4) (E4 G4 C5))

You can get the interval between notes like this:

(difference (note 'g5) (note 'f6)) ;; => MIN7

You can get the note or pitch class an interval above or below another like this:

(above (note 'a♭4) (interval 'p8)) ;; => A♭5

(below (pitch-class 'd) (interval 'aug2)) ;; => C♭

You can add intervals like this:

(sum (interval 'maj6) (interval 'maj3) ;; => AUG8

Why not stack 100 perfect fifths together and see what you get?

(loop:with i = (interval 'p1) :repeat100:do (setf i (sum i (interval 'p5))) :finally (return i)) ;; => 14AUG401

You can get relative or parallel keys like this:

(parallel (key 'f-major) 'minor) ;; => F-MINOR (relative (key 'f♯-minor) 'mixolydian) ;; => E-MIXOLYDIAN

You can make a sequence like this:

(seq '(> sol la < ri mi re me re dodo re))

You can make a chord like this:

(chord '(do mi sol te))

You can designate rhythms using divisions of beats like this:

;; "one and two and three and four (22222212222221) ;; twinkle twinkle;; "one-ee uh ee-and three four" (4224211) ;; mario theme opening rhythm

And you can give rhythm to a sequence like this:

(seq '(> sol la < ri mi re me re dodo re) '(2242444222))

You can play things with live midi using portmidi like this:

(play (seq '(> sol la < ri mi re me re dodo re) '(2242444222)))

Which implicitely wraps the expression in event first:

(event (seq '(> sol la < ri mi re me re dodo re) '(2242444222))) ;; => (G4@0s-1/4s A4@1/4s-1/2s D♯4@1/2s-5/8s E4@5/8s-7/8s D4@7/8s-1s E♭4@1s-9/8s D4@9/8s-5/4s C4@5/4s-3/2s C4@3/2s-7/4s D4@7/4s-2s)

Which turns the expression into a list of timed events.