;;;
;;;
;;; 220b: Assignment 2
;;;
;;; 
;;; Let's start by importing all events from all tracks of a midi file
;;; (http://ccrma.stanford.edu/courses/220b/cm/doc/dict/import-events-fn.html)

(defparameter adagi (import-events "/zap/al_adagi.mid"))

;;; so, what is inside adagi? Type adagi in the lisp interpreter:

adagi

;;; and it should respond with something like this:

CM> adagi
(#<seq "al_adagi-track-0"> #<seq "al_adagi-track-1"> #<seq "al_adagi-track-2">
 #<seq "al_adagi-track-3"> #<seq "al_adagi-track-4"> #<seq "al_adagi-track-5">
 #<seq "al_adagi-track-6"> #<seq "al_adagi-track-7"> #<seq "al_adagi-track-8">
 #<seq "al_adagi-track-9"> #<seq "al_adagi-track-10">
 #<seq "al_adagi-track-11">)
CM> 

;;; so, adagi is a sequence that contains sequences,
;;; this is a multitrack midi file, we probably want to
;;; only read one track (to analyze it later)

;;; we can restrict the read to track #1 (track is zero based)

(defparameter adagi (import-events "/zap/al_adagi.mid" :tracks 1))

;;; adagi will now contain only the second track...

CM> adagi
#<seq "al_adagi-track-1">
CM> 

;;; how do we get to the notes?
;;; those are subobjects in the sequence object, we could extract
;;; them as a list:

(subobjects adagi)

;;; see http://ccrma.stanford.edu/courses/220b/cm/doc/dict/subobjects-fn.html

;;; this should print a list of all subobjects, in this case midi notes

;;; we can, of course, iterate over them with loop,
;;; this will again print all events, one per line:

(loop for e in (subobjects adagi)
      do (format t "~s~%" e))

;;; now, we only need the key number of each event (to feed to markov),
;;; "sv" (slot value) will retrieve a given slot (:keynum in this case)
;;; from an object:

(loop for e in (subobjects adagi)
      do (format t "~s~%" (sv e :keynum)))

;;; see: http://ccrma.stanford.edu/courses/220b/cm/doc/dict/sv-mac.html

;;; but most probably this will fail with an error!
;;; not all midi event types have a keynum slot!

;;; so we should check the object to see if it has a keynum parameter
;;; _before_ trying to access it...

(loop for e in (subobjects adagi)
      do (format t "~s~%" 
		 ;; does the object have a keynum parameter?
		 (if (member 'keynum (object-parameters e))
		     ;; yes, so access it!
		     (sv e :keynum))))

;;; that should have printed numbers, those are the key numbers of
;;; all the notes contained in the sequence

;;; of course instead of printing we could collect them in a list,
;;; which by coincidence is what markov-analyse needs :-)

;;; you will want to learn about "markov-analyze" here:
;;; http://ccrma.stanford.edu/courses/220b/cm/doc/dict/markov-analyze-fn.html

;;; and of course about the markov pattern class as well:
;;; http://ccrma.stanford.edu/courses/220b/cm/doc/dict/markov-cls.html