2 ;;; Generate chord names for the parser.
6 (define-public (construct-chord root duration modifications)
8 " Build a chord on root using modifiers in MODIFICATIONS. NoteEvent
9 have duration DURATION..
11 Notes: natural 11 is left from chord if not explicitly specified.
13 Entry point for the parser.
18 (flat-mods (flatten-list modifications))
19 (base-chord (stack-thirds (ly:make-pitch 0 4 0) the-canonical-chord))
28 (define (interpret-inversion chord mods)
29 "Read /FOO part. Side effect: INVERSION is set."
31 (if (and (> (length mods) 1) (eq? (car mods) 'chord-slash))
33 (set! inversion (cadr mods))
34 (set! mods (cddr mods))))
36 (interpret-bass chord mods))
38 (define (interpret-bass chord mods)
39 "Read /+FOO part. Side effect: BASS is set."
41 (if (and (> (length mods) 1) (eq? (car mods) 'chord-bass))
43 (set! bass (cadr mods))
44 (set! mods (cddr mods))))
47 (scm-error 'chord-format "construct-chord" "Spurious garbage following chord: ~A" mods #f)
53 (define (interpret-removals chord mods)
54 (define (inner-interpret chord mods)
55 (if (and (pair? mods) (ly:pitch? (car mods)))
57 (remove-step (+ 1 (ly:pitch-steps (car mods))) chord)
59 (interpret-inversion chord mods))
62 (if (and (pair? mods) (eq? (car mods) 'chord-caret))
63 (inner-interpret chord (cdr mods))
64 (interpret-inversion chord mods))
68 (define (interpret-additions chord mods)
69 "Interpret additions. TODO: should restrict modifier use?"
72 ((ly:pitch? (car mods))
73 (if (= (ly:pitch-steps (car mods)) 11)
74 (set! explicit-11 #t))
76 (cons (car mods) (remove-step (pitch-step (car mods)) chord))
78 ((procedure? (car mods))
82 (else (interpret-removals chord mods))
84 (define (pitch-octavated-below p root)
85 "return P, but octavated, so it is below ROOT"
88 (ly:pitch-octave root)
89 (if (>= (ly:pitch-notename root)
90 (ly:pitch-notename p))
93 (ly:pitch-alteration p)))
95 (define (process-inversion complete-chord)
96 "Take out inversion from COMPLETE-CHORD, and put it at the bottom.
97 Return (INVERSION . REST-OF-CHORD).
99 Side effect: put original pitch in INVERSION.
100 If INVERSION is not in COMPLETE-CHORD, it will be set as a BASS, overriding
106 (root (car complete-chord))
108 (and (= (ly:pitch-notename y)
109 (ly:pitch-notename inversion))
110 (= (ly:pitch-alteration y)
111 (ly:pitch-alteration inversion))
114 (rest-of-chord (filter-out-list inv? complete-chord))
115 (inversion-candidates (filter-list inv? complete-chord))
116 (down-inversion (pitch-octavated-below inversion root))
119 (if (pair? inversion-candidates)
120 (set! inversion (car inversion-candidates))
122 (set! bass inversion)
126 (cons down-inversion rest-of-chord)
131 ;; root is always one octave too low.
133 ; something weird happens when this is removed,
134 ; every other chord is octavated. --hwn... hmmm.
135 (set! root (ly:pitch-transpose root (ly:make-pitch 1 0 0)))
139 (write-me "\n*******\n" flat-mods)
140 (write-me "root: " root)
141 (write-me "base: " base-chord)
142 (write-me "bass: " bass)))
144 ;; skip the leading : , we need some of the stuff following it.
145 (if (pair? flat-mods)
146 (if (eq? (car flat-mods) 'chord-colon)
147 (set! flat-mods (cdr flat-mods))
148 (set! start-additions #f)
152 (if (and (pair? flat-mods) (procedure? (car flat-mods)))
154 (set! lead-mod (car flat-mods))
155 (set! flat-mods (cdr flat-mods))
158 ;; extract first number if present, and build pitch list.
159 (if (and (pair? flat-mods)
160 (ly:pitch? (car flat-mods))
161 (not (eq? lead-mod sus-modifier))
165 (if (= (pitch-step (car flat-mods)) 11)
166 (set! explicit-11 #t))
168 (map (lambda (y) (ly:pitch-transpose y root))
169 (stack-thirds (car flat-mods) the-canonical-chord)))
170 (set! flat-mods (cdr flat-mods))
174 (if (procedure? lead-mod)
175 (set! base-chord (lead-mod base-chord)))
180 (interpret-additions base-chord flat-mods)
181 (interpret-removals base-chord flat-mods)
185 (set! complete-chord (map (lambda (x) (ly:pitch-transpose x root))
186 (sort complete-chord ly:pitch<?)))
188 ;; If natural 11 + natural 3 is present, but not given explicitly,
190 (if (and (not explicit-11)
191 (get-step 11 complete-chord)
192 (get-step 3 complete-chord)
193 (= 0 (ly:pitch-alteration (get-step 11 complete-chord)))
194 (= 0 (ly:pitch-alteration (get-step 3 complete-chord)))
197 (set! complete-chord (remove-step 11 complete-chord))
201 (set! complete-chord (process-inversion complete-chord)))
203 (set! bass (pitch-octavated-below bass root)))
205 (make-chord (cdr complete-chord) bass duration (car complete-chord)
207 (make-chord complete-chord bass duration #f #f))
211 (define (make-chord pitches bass duration inversion original-inv-pitch)
212 "Make EventChord with notes corresponding to PITCHES, BASS and
213 DURATION, and INVERSION."
214 (define (make-note-ev pitch)
217 (ev (make-music-by-name 'NoteEvent))
220 (ly:set-mus-property! ev 'duration duration)
221 (ly:set-mus-property! ev 'pitch pitch)
227 (nots (map make-note-ev pitches))
228 (bass-note (if bass (make-note-ev bass) #f))
229 (inv-note (if inversion (make-note-ev inversion) #f))
235 (ly:set-mus-property! bass-note 'bass #t)
236 (set! nots (cons bass-note nots))))
241 (ly:set-mus-property! inv-note 'inversion #t)
242 (ly:set-mus-property! inv-note 'original-pitch original-inv-pitch)
243 (set! nots (cons inv-note nots))))
245 (make-event-chord nots)
250 ; chord modifiers change the pitch list.
252 (define (aug-modifier pitches)
253 (set! pitches (replace-step (ly:make-pitch 0 4 1) pitches))
254 (replace-step (ly:make-pitch 0 2 0) pitches)
257 (define (minor-modifier pitches)
258 (replace-step (ly:make-pitch 0 2 -1) pitches)
261 (define (maj7-modifier pitches)
262 (set! pitches (remove-step 7 pitches))
263 (cons (ly:make-pitch 0 6 0) pitches)
266 (define (dim-modifier pitches)
267 (set! pitches (replace-step (ly:make-pitch 0 2 -1) pitches))
268 (set! pitches (replace-step (ly:make-pitch 0 4 -1) pitches))
269 (set! pitches (replace-step (ly:make-pitch 0 6 -2) pitches))
273 (define (sus-modifier pitches)
274 (remove-step (pitch-step (ly:make-pitch 0 2 0)) pitches)
277 (define-public default-chord-modifier-list
278 `((m . ,minor-modifier)
279 (min . ,minor-modifier)
280 (aug . , aug-modifier)
281 (dim . , dim-modifier)
282 (maj . , maj7-modifier)
283 (sus . , sus-modifier)
287 ;; canonical 13 chord.
288 (define the-canonical-chord
294 (ly:make-pitch 1 (- n 8) (nca n))
295 (ly:make-pitch 0 (- n 1) (nca n))))
298 (define (stack-thirds upper-step base)
299 "Stack thirds listed in BASE until we reach UPPER-STEP. Add
300 UPPER-STEP separately."
303 ((> (ly:pitch-steps upper-step) (ly:pitch-steps (car base)))
304 (cons (car base) (stack-thirds upper-step (cdr base))))
305 ((<= (ly:pitch-steps upper-step) (ly:pitch-steps (car base)))