annotate base/classes.lisp @ 115:cf198383852d

Re-instated get-applicable-x for midi-related implementations and added key-sigs to midi

darcs-hash:20070726144704-f76cc-a24c9e6c07b43c4084a73218f76a0b345fac5369.gz

(cl:in-package #:amuse) 

;; collections of more than one event

(defclass constituent (anchored-period) ())
(defclass time-ordered-constituent (constituent list-slot-sequence)
  ;; this won't work if lisp implementation doesn't support extensible
  ;; sequences.
  ())
(defclass composition (time-ordered-constituent) ())
(defclass monody (composition) ())

;; types of information-specifiers

(defclass identifier () ()) ;; for composition specification
(defclass moment-designator () ()
  (:documentation "Object indicating a point in time"))
(defclass period-designator () ()
  (:documentation "Object indicating a region of time"))
(defclass anchored-period-designator (moment-designator period-designator) ()
  (:documentation "Object indicating a region of time starting at
  a specific point in time"))
(defclass pitch-designator () ()
  (:documentation "Object indicating some sort of pitch"))
(defclass pitch-interval-designator () ()
  (:documentation "Object indicating a distance in pitch space"))

;; time-related classes

(defclass moment (moment-designator) 
  ((time :accessor %moment-time :initarg :time))
  (:documentation "A moment represented on a number line"))

(defclass period (period-designator) 
  ((interval :accessor %period-interval :initarg :interval))
  (:documentation "A number-line-based period"))

(defclass floating-period (period) ()
  (:documentation "A simple numeric period"))
(defclass anchored-period (period moment anchored-period-designator) ()
  (:documentation "Number-line-based anchored period"))

;; pitch-related classes

(defclass frequency () ())

(defclass pitch (pitch-designator) ())
(defclass chromatic-pitch (pitch) 
  ((number :accessor %chromatic-pitch-number :initarg :number))
  (:documentation "A pitch represented as a number, with higher
  values representing high pitches."))
(defclass diatonic-pitch (pitch) 
  ((cp :initarg :cp :accessor %p-pc :reader diatonic-pitch-cp)
   (mp :initarg :mp :accessor %p-pm :reader diatonic-pitch-mp))
  (:documentation "A diatonic pitch, represented using MIPS: cp is an
integer representing chromatic pitch (An0 = 0, middle C = 39); mp is
an integer representing the morphetic pitch (An0 = 0, middle C =
23)."))

(defclass chromatic-pitch-interval (pitch-interval-designator) 
  ((span :accessor %chromatic-pitch-interval-span :initarg :span)))

(defclass diatonic-pitch-interval (pitch-interval-designator)
  ((span :accessor %diatonic-pitch-interval-span :initarg :span :reader span)))

;; events

(defclass event (anchored-period) ())
(defclass pitched-event (event pitch-designator) ())
(defclass chromatic-pitched-event (pitched-event chromatic-pitch) ())
(defclass percussive-event (event) ())

;;; Range-based `constituents'
;; Whilst these are all constituents in the CHARM sense, their
;; properties apply to a timed range rather than to a set of
;; events. As such, they can be regarded as anchored-periods with
;; properties.

(defclass time-signature (anchored-period) ())

(defclass basic-time-signature (time-signature)
  ;; N.B. Can only deal with numeric signatures
  ((numerator :accessor %basic-time-signature-numerator
	      :initarg :numerator)
   (denominator :accessor %basic-time-signature-denominator
		:initarg :denominator)))

(defclass key-signature (anchored-period) ())

(defclass basic-key-signature (key-signature)
  ;; Only has line-of-fifths distance from c, so custom signatures
  ;; won't work
  ((sharp-count :accessor %basic-key-signature-sharp-count
		:initarg :sharp-count)))

(defclass midi-key-signature (basic-key-signature)
  ;; mode: 0 = major key; 1 = minor key
  ((mode :accessor %midi-key-signature-mode
	 :initarg :mode)))

(defclass tempo (anchored-period)
  ;; accel and rit in symbolic encoding will need other structures, as
  ;; will textual tempo markings.
  ((bpm :accessor %tempo-bpm
	:initarg :bpm)))