1 ;;;; fret-diagrams.scm --
3 ;;;; source file of the GNU LilyPond music typesetter
5 ;;;; (c) 2004 Carl D. Sorensen <c_sorensen@byu.edu>
7 (define ly:paper-lookup ly:output-def-lookup) ; compat for 2.3, remove when using 2.2
9 ;;TODO -- Change font interface from name, magnification to family, weight, size
10 ; Right now, using the desired interface gives an error, so we use name, magnification
12 (define (fret-parse-marking-list marking-list fret-count)
13 (let* ((fret-range (list 1 fret-count))
18 (let parse-item ((mylist marking-list))
19 (if (not (null? mylist))
20 (let* ((my-item (car mylist)) (my-code (car my-item)))
22 ((or (eq? my-code 'open)(eq? my-code 'mute))
23 (set! xo-list (cons* my-item xo-list)))
25 (set! barre-list (cons* (cdr my-item) barre-list)))
26 ((eq? my-code 'place-fret)
27 (set! dot-list (cons* (cdr my-item) dot-list))))
28 (parse-item (cdr mylist)))))
29 ; calculate fret-range
30 (let ((maxfret 0) (minfret 99))
31 (let updatemax ((fret-list dot-list))
34 (let ((fretval (second (car fret-list))))
35 (if (> fretval maxfret) (set! maxfret fretval))
36 (if (< fretval minfret) (set! minfret fretval))
37 (updatemax (cdr fret-list)))))
38 (if (> maxfret fret-count)
39 (set! fret-range (list minfret
40 (let ((upfret (- (+ minfret fret-count) 1)))
41 (if (> maxfret upfret) maxfret upfret)))))
42 ; subtract fret from dots
43 (set! dot-list (subtract-base-fret (- (car fret-range) 1) dot-list)))
44 (acons 'fret-range fret-range
45 (acons 'barre-list barre-list
46 (acons 'dot-list dot-list
47 (acons 'xo-list xo-list '()))))))
49 (define (subtract-base-fret base-fret dot-list)
50 "Subtract @var{base-fret} from every fret in @var{dot-list}"
53 (let ((this-list (car dot-list)))
54 (cons* (list (car this-list) (- (second this-list) base-fret) (if (null? (cddr this-list))
57 (subtract-base-fret base-fret (cdr dot-list))))))
59 (define (draw-strings string-count fret-range th size)
60 "Draw the strings (vertical lines) for a fret diagram with @var{string-count} strings and frets as indicated
61 in @var{fret-range}. Line thickness is given by @var{th}, fret & string spacing by @var{size}. "
62 (let* ((fret-count (+ (- (cadr fret-range) (car fret-range)) 1))
63 (sl (* (+ fret-count 1) size))
65 (half-thickness (* sth 0.5))
67 (string-stencil (ly:make-stencil (list 'draw-line sth 0 0 0 sl)
68 (cons (- half-thickness) half-thickness)
69 (cons (- half-thickness) (+ sl half-thickness)))))
70 (if (= string-count 1)
72 (ly:stencil-combine-at-edge
73 (draw-strings (- string-count 1) fret-range th size) X RIGHT
77 (define (draw-fret-lines fret-count string-count th size)
78 "Draw @var{fret-count} frets (horizontal lines) for a fret diagram with @var{string-count} strings.
79 Line thickness is given by @var{th}, fret & string spacing by @var{size}. "
80 (let* ((fret-length (* (- string-count 1) size))
82 (half-thickness (* sth 0.5))
84 (fret-line (ly:make-stencil (list 'draw-line sth half-thickness size (- fret-length half-thickness) size)
86 (cons (- size half-thickness) (+ size half-thickness)))))
89 (ly:stencil-combine-at-edge fret-line Y UP
90 (draw-fret-lines (- fret-count 1) string-count th size)
93 (define (draw-thick-top-fret props string-count th size)
94 "Draw a thick top fret for a fret diagram whose base fret is not 1."
95 (let* ((sth (* th size))
96 (top-fret-thick (* sth (chain-assoc-get 'top-fret-thickness props 3.0)))
97 (top-half-thick (* top-fret-thick 0.5))
98 (half-thick (* sth 0.5))
100 (x2 (+ half-thick (* size (- string-count 1))))
103 (x-extent (cons (- x1) x2))
104 (y-extent (cons 0 y2)))
105 (ly:make-stencil (list 'round-filled-box x1 x2 y1 y2 th)
109 (define (draw-frets paper props fret-range string-count th size)
110 "Draw the frets (horizontal lines) for a fret diagram with @var{string-count} strings and frets as indicated
111 in @var{fret-range}. Line thickness is given by @var{th}, fret & string spacing by @var{size}. "
112 (let* ((top-fret-thick (* th (chain-assoc-get 'top-fret-thickness props 3.0)))
113 (fret-count (+ (- (cadr fret-range) (car fret-range)) 1))
114 (fret-length (* (- string-count 1) size))
115 (half-thickness (* th 0.5))
116 (base-fret (car fret-range)))
117 (ly:stencil-combine-at-edge
118 (draw-fret-lines fret-count string-count th size) Y UP
120 (draw-thick-top-fret props string-count th size)
121 (draw-fret-lines 1 string-count th size))
125 (define (centered-text-stencil procedure font text)
126 "Create a centered text stencil of @var{text} in font @var{font} using stencil creation procedure @var{procedure}"
127 ;UGH -- version check is necessary because 2.3 is not available on cygwin, so CDS development
128 ; needs 2.2 compatible ly:stencil-align-to!
129 ; Once 2.3 is built on cygwin, version check can go (fret-diagrams.scm is not part of dist for 2.2)
130 (let* ((text-stencil (procedure font text)))
131 (if (= (cadr (ly:version)) 3)
133 (ly:stencil-align-to! text-stencil Y 0)
134 (ly:stencil-align-to! text-stencil X 0)
136 (ly:stencil-align-to (ly:stencil-align-to text-stencil X 0) Y 0))))
138 (define (draw-dots paper props string-count fret-range size finger-code dot-circle-font-mag dot-position dot-radius dot-list)
139 "Make dots for fret diagram."
140 ;TODO -- move away from name,magnification font spec to family, size
141 ; Note -- family, size doesn't work with fontify-text procedure; need to fix that before we can make the switch
142 (let* ((scale-dot-radius (* size dot-radius))
143 (dot-color (chain-assoc-get 'dot-color props 'black))
144 (finger-xoffset (chain-assoc-get 'finger-xoffset props -0.25))
145 (finger-yoffset (chain-assoc-get 'finger-yoffset props (- size)))
146 ;part of deprecated font interface
147 (label-font-name (chain-assoc-get 'label-font-name props "cmss8"))
148 (dot-label-font-mag (* scale-dot-radius (chain-assoc-get 'dot-label-font-mag props 1.2)))
149 (string-label-font-mag (* size (chain-assoc-get 'string-label-font-mag props 0.6)))
150 (fret-count (+ (- (cadr fret-range) (car fret-range) 1)))
151 (mypair (car dot-list))
152 (restlist (cdr dot-list))
153 (xpos (* size (- string-count (car mypair))))
154 ;TODO -- figure out what 4 is and get rid of it
156 (ypos (* size (+ 4 (- fret-count (cadr mypair) dot-position ))))
157 (extent (cons (- scale-dot-radius) scale-dot-radius))
158 (finger (caddr mypair))
159 (finger (if (number? finger) (number->string finger) finger))
160 ; desired font interface
161 (string-label-font (ly:paper-get-font paper `(((font-family . sans)(font-encoding . latin1)(font-series . medium) (font-shape . upright)
162 (font-size . ,(stepmag (* size string-label-font-mag)))))))
163 ; deprecated font interface
164 ; (string-label-font (ly:paper-get-font paper `(((font-magnification . ,string-label-font-mag)
165 ; (font-name . ,label-font-name)))))
166 ; desired font interface
167 (dot-label-font (ly:paper-get-font paper `(((font-family . sans)(font-encoding . latin1)(font-series . medium) (font-shape . upright)
168 (font-size . ,(stepmag (* size dot-label-font-mag)))))))
169 ; deprecated font interface
170 ; (dot-label-font (ly:paper-get-text-font paper `(((font-magnification . ,dot-label-font-mag)
171 ; (font-name . ,label-font-name)))))
172 ; desired font interface
173 (dot-circle-font (ly:paper-get-font paper `(((font-family . sans)(font-encoding . latin1)(font-series . medium) (font-shape . upright)
174 (font-size . ,(stepmag (* size dot-circle-font-mag)))))))
175 ; deprecated font interface
176 ; (dot-circle-font (ly:paper-get-font paper `(((font-magnification . ,dot-circle-font-mag)
177 ; (font-name . ,label-font-name)))))
178 (dotstencil (if (eq? dot-color 'white)
180 (ly:make-stencil (list 'white-dot 0 0 scale-dot-radius) extent extent))
181 (ly:make-stencil (list 'dot 0 0 scale-dot-radius ) extent extent)))
182 (positioned-dot (ly:stencil-translate-axis
183 (ly:stencil-translate-axis dotstencil xpos X)
186 (if (or (eq? finger '())(eq? finger-code 'none))
188 (if (eq? finger-code 'in-dot)
189 (let* ((dot-proc (if (eq? dot-color 'white) 'white-dot 'dot))
190 (text-proc (if (eq? dot-color 'white) fontify-text fontify-text-white)))
192 (ly:stencil-translate-axis
193 (ly:stencil-translate-axis
194 (centered-text-stencil text-proc dot-label-font finger) xpos X)
196 (ly:stencil-translate-axis
197 (ly:stencil-translate-axis
198 (ly:make-stencil (list dot-proc 0 0 scale-dot-radius) extent extent)
201 (if (eq? finger-code 'below-string)
204 (ly:stencil-translate-axis
205 (ly:stencil-translate-axis
206 (centered-text-stencil fontify-text string-label-font finger) xpos X)
207 (* size finger-yoffset) Y))
213 (draw-dots paper props string-count fret-range size finger-code dot-circle-font-mag
214 dot-position dot-radius restlist)
215 labeled-dot-stencil))))
217 (define (draw-xo paper props string-count fret-range size xo-list)
218 "Put open and mute string indications on diagram, as contained in @var{xo-list}."
219 ;TODO -- Move away from name,mag font spec to family, size
220 (let* ((fret-count (+ (- (cadr fret-range) (car fret-range) 1)))
221 (xo-font-mag (* size (chain-assoc-get 'xo-font-magnification props 0.5)))
222 (xo-font-name (chain-assoc-get 'xo-font-name props "cmss8"))
223 (xo-horizontal-offset (* size (chain-assoc-get 'xo-horizontal-offset props -0.35)))
224 ; desired font interface
225 ; (font (ly:paper-get-font paper `(((font-family . sans)(font-series . medium) (font-shape . upright)
226 ; (font-size . ,(stepmag (* size xo-font-mag)))))))
227 ; deprecated font interface
228 (font (ly:paper-get-font paper `(((font-magnification . ,xo-font-mag)
229 (font-name . ,xo-font-name)))))
230 (mypair (car xo-list))
231 (restlist (cdr xo-list))
232 (glyph-string (if (eq? (car mypair) 'mute) "X" "O"))
233 (xpos (+ (* (- string-count (cadr mypair)) size) xo-horizontal-offset ))
234 (glyph-stencil (ly:stencil-translate-axis (fontify-text font glyph-string) xpos X)))
238 (draw-xo paper props string-count fret-range size restlist)
241 (define (make-bezier-sandwich-list left right bottom height thickness)
242 " Make the argument list for a horizontal bezier sandwich from @var{left} to @var{right} with a bottom at @var{bottom},
243 a height of @var{height}, and a thickness of @var{thickness}."
244 (let* ((width (+ (- right left) 1))
245 (x1 (+ (* width thickness) left))
246 (x2 (- right (* width thickness)))
247 (bottom-control-point-height (+ bottom (- height thickness)))
248 (top-control-point-height (+ bottom height)))
249 ; order of points is: left cp low, right cp low, right end low, left end low
250 ; right cp high, left cp high, left end high, right end high.
251 (list (cons x1 bottom-control-point-height) (cons x2 bottom-control-point-height) (cons right bottom) (cons left bottom)
252 (cons x2 top-control-point-height) (cons x1 top-control-point-height) (cons left bottom) (cons right bottom))))
254 (define (draw-barre paper props string-count fret-range size finger-code dot-circle-font-mag dot-position dot-radius barre-list)
255 "Create barre indications for a fret diagram"
256 (if (not (null? barre-list))
257 (let* ((string1 (caar barre-list))
258 (string2 (cadar barre-list))
259 (fret (caddar barre-list))
260 (barre-type (chain-assoc-get 'barre-type props 'curved))
261 (scale-dot-radius (* size dot-radius))
262 (barre-vertical-offset (chain-assoc-get 'barre-vertical-offset props 0.5))
263 ; 2 is 1 for empty fret at bottom of figure + 1 for interval (top-fret - fret + 1) -- not an arbitrary constant
264 (dot-center-y (* size (- (+ 2 (- (cadr fret-range) fret))dot-position) ))
265 (bottom (+ dot-center-y (* barre-vertical-offset scale-dot-radius)))
266 (left (* size (- string-count string1)))
267 (right (* size (- string-count string2)))
268 (bezier-thick (chain-assoc-get 'bezier-thickness props 0.1))
269 (bezier-height (chain-assoc-get 'bezier-height props 0.5))
270 (bezier-list (make-bezier-sandwich-list left right bottom (* size bezier-height) (* size bezier-thick)))
271 (barre-stencil (if (eq? barre-type 'straight)
272 (ly:make-stencil (list 'draw-line (* size dot-radius) left dot-center-y right dot-center-y)
274 (cons (- dot-center-y scale-dot-radius) (+ dot-center-y scale-dot-radius)))
275 (ly:make-stencil (list 'bezier-sandwich `(quote ,bezier-list) (* size bezier-thick) )
277 (cons bottom (+ bottom (* size bezier-height)))))))
278 (if (not (null? (cdr barre-list)))
279 (ly:stencil-add barre-stencil
280 (draw-barre paper props string-count fret-range size finger-code dot-circle-font-mag
281 dot-position dot-radius (cdr barre-list)))
285 (define (stepmag mag)
286 "Calculate the font step necessary to get a desired magnification"
287 (* 6 (/ (log mag) (log 2))))
289 (define (label-fret paper props string-count fret-range size)
290 "Label the base fret on a fret diagram"
291 ;TODO -- move away from name,magnification font spec to family, size
292 (let* ((base-fret (car fret-range))
293 (label-font-mag (chain-assoc-get 'fret-label-font-magnification props 0.7))
294 ; (label-horizontal-offset (chain-assoc-get 'fret-label-horizontal-offset props -0.5))
295 (label-vertical-offset (chain-assoc-get 'fret-label-vertical-offset props -0.2))
296 (fret-count (+ (- (cadr fret-range) (car fret-range)) 1))
297 ; desired font interface
298 ; (font (ly:paper-get-font paper `(((font-family . sans)(font-series . medium) (font-shape . upright)
299 ; (font-size . ,(stepmag (* size label-font-mag))))))))
300 ; deprecated font interface
301 (font (ly:paper-get-font paper `(((font-magnification . ,label-font-mag)
302 (font-name . "cmss8"))))))
303 (ly:stencil-translate-axis (fontify-text font (format #f "~(~:@r~)" base-fret))
304 (* size (+ fret-count label-vertical-offset)) Y)))
306 (def-markup-command (fret-diagram-verbose paper props marking-list)
308 ;TODO -- put table in doc string
309 "Make a fret diagram containing the symbols indicated in @var{marking-list}
311 Syntax: \\fret-diagram marking-list
316 \\markup \\fret-diagram #'((mute 6) (mute 5) (open 4) (place-fret 3 2) (place-fret 2 3) (place-fret 1 2))
319 will produce a standard D chord diagram without fingering indications.
321 Possible elements in @var{marking-list}:
323 @item (mute string-number)
324 Place a small 'x' at the top of string @var{string-number}
326 @item (open string-number)
327 Place a small 'o' at the top of string @var{string-number}
329 @item (barre start-string end-string fret-number)
330 Place a barre indicator (much like a tie) from string @var{start-string}to string @var{end-string} at fret @var{fret-number}
332 @item (place-fret string-number fret-number finger-value)
333 Place a fret playing indication on string @var{string-number} at fret @var{fret-number} with an optional
334 fingering label @var{finger-value}. By default, the fret playing indicator is a solid dot. This can be
335 changed by setting the value of the variable @var{dot-color}. If the @var{finger}
336 part of the place-fret element is present, @var{finger-value} will be displayed according to the setting of the variable
337 @var{finger-code}. There is no limit to the number of fret indications per string.
340 (make-fret-diagram paper props marking-list))
342 (define (make-fret-diagram paper props marking-list)
343 " Make a fret diagram markup"
345 ; note: here we get items from props that are needed in this routine, or that are needed in more than one
346 ; of the procedures called from this routine. If they're only used in one of the sub-procedure, they're
347 ; obtained in that procedure
349 (size (chain-assoc-get 'size props 1.0)) ; needed for everything
350 ;TODO -- get string-count directly from length of stringTunings; requires FretDiagram engraver, which is not yet available
351 ;TODO -- adjust padding for fret label? it appears to be too close to dots
352 (string-count (chain-assoc-get 'string-count props 6)) ; needed for everything
353 (fret-count (chain-assoc-get 'fret-count props 4)) ; needed for everything
354 (finger-code (chain-assoc-get 'finger-code props 'none)) ; needed for both draw-dots and draw-barre
355 (default-dot-radius (if (eq? finger-code 'in-dot) 0.45 0.25)) ; bigger dots if labeled
356 (default-dot-position (if (eq? finger-code 'in-dot) 0.5 0.6)) ; move up to make room for bigger if labeled
357 (dot-radius (chain-assoc-get 'dot-radius props default-dot-radius)) ; needed for both draw-dots and draw-barre
358 (dot-position (chain-assoc-get 'dot-position props default-dot-position)) ; needed for both draw-dots and draw-barre
359 (dot-circle-font-mag (* size (chain-assoc-get 'dot-circle-font-mag props .75))) ; needed for both draw-dots and draw-barre
360 (th (* (ly:paper-lookup paper 'linethickness)
361 (chain-assoc-get 'thickness props 0.5))) ; needed for both draw-frets and draw-strings
363 (alignment (chain-assoc-get 'alignment props -0.4)) ; needed only here
364 (xo-padding (* th (chain-assoc-get 'xo-padding props 2))) ; needed only here
366 (parameters (fret-parse-marking-list marking-list fret-count))
367 (dot-list (cdr (assoc 'dot-list parameters)))
368 (xo-list (cdr (assoc 'xo-list parameters)))
369 (fret-range (cdr (assoc 'fret-range parameters)))
370 (barre-list (cdr (assoc 'barre-list parameters)))
371 (fret-diagram-stencil (ly:stencil-add
372 (draw-strings string-count fret-range th size)
373 (draw-frets paper props fret-range string-count th size))))
374 (if (not (null? barre-list))
375 (set! fret-diagram-stencil (ly:stencil-add
376 (draw-barre paper props string-count fret-range size finger-code dot-circle-font-mag
377 dot-position dot-radius barre-list)
378 fret-diagram-stencil)))
379 (if (not (null? dot-list))
380 (set! fret-diagram-stencil (ly:stencil-add
381 (draw-dots paper props string-count fret-range size finger-code dot-circle-font-mag
382 dot-position dot-radius dot-list)
383 fret-diagram-stencil)))
384 (if (not (null? xo-list))
385 (set! fret-diagram-stencil (ly:stencil-combine-at-edge
386 fret-diagram-stencil Y UP
387 (draw-xo paper props string-count fret-range size xo-list) xo-padding 0)))
388 (if (> (car fret-range) 1)
389 (set! fret-diagram-stencil
390 (ly:stencil-combine-at-edge fret-diagram-stencil X RIGHT
391 (label-fret paper props string-count fret-range size) 0 0)))
392 (ly:stencil-align-to! fret-diagram-stencil X alignment)
393 fret-diagram-stencil))
395 (def-markup-command (fret-diagram paper props definition-string)
397 ;TODO -- put table in doc string
398 "Syntax: \\fret-diagram definition-string
400 eg: \\markup \\fret-diagram #\"s:0.75;6-x;5-x;4-o;3-2;2-3;1-2;\"
402 for fret spacing 3/4 of staff space, D chord diagram
404 Syntax rules for @var{definition-string}:
408 Diagram items are separated by semicolons.
415 s:number -- set the fret spacing of the diagram (in staff spaces). Default 1
418 t:number -- set the line thickness (in staff spaces). Default 0.05
421 h:number -- set the height of the diagram in frets. Default 4
424 w:number -- set the width of the diagram in strings. Default 6
427 f:number -- set fingering label type (0 = none, 1 = in circle on string, 2 = below string) Default 0
430 d:number -- set radius of dot, in terms of fret spacing. Default 0.25
433 p:number -- set the position of the dot in the fret space. 0.5 is centered; 1 is on lower fret bar,
434 0 is on upper fret bar. Default 0.6
437 c:string1-string2-fret -- include a barre mark from string1 to string2 on fret
440 string-fret -- place a dot on string at fret. If fret is o, string is identified
441 as open. If fret is x, string is identified as muted.
444 string-fret-fingering -- place a dot on string at fret, and label with fingering as
450 Note: There is no limit to the number of fret indications per string.
454 ; (define new-props (acons 'size size '()))
455 ; (set! props (cons new-props props))
456 (let ((definition-list (fret-parse-definition-string props definition-string)))
457 (make-fret-diagram paper (car definition-list) (cdr definition-list))))
459 (define (fret-parse-definition-string props definition-string)
460 "parse a fret diagram string and return a pair containing:
461 props, modified as necessary by the definition-string
462 a fret-indication list with the appropriate values"
463 (let* ((fret-count 4)
469 (fret-range (list 1 fret-count))
475 (items (string-split definition-string #\;)))
476 (let parse-item ((myitems items))
477 (if (not (null? (cdr myitems)))
478 (let ((test-string (car myitems)))
479 (case (car (string->list (substring test-string 0 1)))
480 ((#\s) (let ((size (get-numeric-from-key test-string)))
481 (set! new-props (acons 'size size new-props))))
482 ((#\f) (let* ((finger-code (get-numeric-from-key test-string))
483 (finger-id (case finger-code
486 ((2) 'below-string))))
488 (acons 'finger-code finger-id new-props))))
489 ((#\c) (set! output-list (cons-fret (cons 'barre (numerify (string-split (substring test-string 2) #\-)))
491 ((#\h) (let ((fret-count (get-numeric-from-key test-string)))
492 (set! new-props (acons 'fret-count fret-count new-props))))
493 ((#\w) (let ((string-count (get-numeric-from-key test-string)))
494 (set! new-props (acons 'string-count string-count new-props))))
495 ((#\d) (let ((dot-size (get-numeric-from-key test-string)))
496 (set! new-props (acons 'dot-radius dot-size new-props))))
497 ((#\p) (let ((dot-position (get-numeric-from-key test-string)))
498 (set! new-props (acons 'dot-position dot-position new-props))))
500 (let ((this-list (string-split test-string #\-)))
501 (if (string->number (cadr this-list))
502 (set! output-list (cons-fret (cons 'place-fret (numerify this-list)) output-list))
503 (if (equal? (cadr this-list) "x" )
504 (set! output-list (cons-fret (list 'mute (string->number (car this-list))) output-list))
505 (set! output-list (cons-fret (list 'open (string->number (car this-list))) output-list)))))))
506 (parse-item (cdr myitems)))))
507 (if (eq? new-props '())
508 `(,props . ,output-list)
509 `(,(cons new-props props) . ,output-list))))
511 (define (cons-fret new-value old-list)
512 " Put together a fret-list in the format desired by parse-string "
513 (if (eq? old-list '())
515 (cons* new-value old-list)))
517 (define (get-numeric-from-key keystring)
518 "Get the numeric value from a key of the form k:val"
519 (string->number (substring keystring 2 (string-length keystring) )))
521 (define (numerify mylist)
522 "Convert string values to numeric or character"
525 (let ((numeric-value (string->number (car mylist))))
527 (cons* numeric-value (numerify (cdr mylist)))
528 (cons* (car (string->list (car mylist))) (numerify (cdr mylist)))))))
530 (def-markup-command (fret-diagram-terse paper props definition-string)
532 ;TODO -- put table in doc string
533 "Make a fret diagram markup using terse string-based syntax.
535 Syntax: \\fret-diagram-terse definition-string
537 eg: \\markup \\fret-diagram #\"x;x;o;2;3;2;\" for a D chord diagram.
539 Syntax rules for @var{definition-string}:
543 Strings are terminated by semicolons; the number of semicolons
544 is the number of strings in the diagram.
547 Mute strings are indicated by \"x\".
550 Open strings are indicated by \"o\".
553 A number indicates a fret indication at that fret.
556 If there are multiple fret indicators desired on a string, they
557 should be separated by spaces.
560 Fingerings are given by following the fret number with a \"-\",
561 followed by the finger indicator, e.g. 3-2 for playing the third
562 fret with the second finger.
565 Where a barre indicator is desired, follow the fret (or fingering) symbol
566 with \"-(\" to start a barre and \"-)\" to end the barre.
568 ;TODO -- change syntax to fret\string-finger
569 (let ((definition-list (fret-parse-terse-definition-string props definition-string)))
570 (make-fret-diagram paper (car definition-list) (cdr definition-list))))
572 (define (fret-parse-terse-definition-string props definition-string)
573 "parse a fret diagram string that uses terse syntax; return a pair containing:
574 props, modified to include the string-count determined by the definition-string
575 a fret-indication list with the appropriate values"
576 ;TODO -- change syntax to fret\string-finger
577 ;TODO -- fix bug that doesn't allow multiple indications per string
578 (let* ((barre-start-list '())
581 (items (string-split definition-string #\;))
582 (string-count (- (length items) 1)))
583 (let parse-item ((myitems items))
584 (if (not (null? (cdr myitems)))
585 (let* ((test-string (car myitems))
586 (current-string (- (length myitems) 1))
587 (indicators (string-split test-string #\ )))
588 (let parse-indicators ((myindicators indicators))
589 (if (not (eq? '() myindicators))
590 (let* ((this-list (string-split (car myindicators) #\-))
591 (max-element-index (- (length this-list) 1))
592 (last-element (car (list-tail this-list max-element-index)))
593 (fret (if (string->number (car this-list)) (string->number (car this-list)) (car this-list))))
594 (if (equal? last-element "(") ; here I add ) to balance parentheses for my editor
596 (set! barre-start-list (cons-fret (list current-string fret) barre-start-list))
597 (set! this-list (list-head this-list max-element-index))))
598 (if (equal? last-element ")") ; here I add ( to balance parentheses for my editor
599 (let* ((this-barre (get-sub-list fret barre-start-list))
600 (insert-index (- (length this-barre) 1)))
601 (set! output-list (cons-fret (cons* 'barre (car this-barre) current-string (cdr this-barre))
603 (set! this-list (list-head this-list max-element-index))))
605 (set! output-list (cons-fret (cons* 'place-fret current-string (drop-paren (numerify this-list))) output-list))
606 (if (equal? (car this-list) "x" )
607 (set! output-list (cons-fret (list 'mute current-string) output-list))
608 (set! output-list (cons-fret (list 'open current-string) output-list))))
609 (parse-indicators (cdr myindicators)))))
610 (parse-item (cdr myitems)))))
611 (set! new-props (acons 'string-count string-count new-props))
613 `(,(cons new-props props) . ,output-list)))
615 (define (drop-paren item-list)
616 " drop a final parentheses from a fret indication list resulting from a terse string specification of barre."
617 (if (> (length item-list) 0)
618 (let* ((max-index (- (length item-list) 1))
619 (last-element (car (list-tail item-list max-index))))
620 (if (or (equal? last-element ")") (equal? last-element "("))
621 (list-head item-list max-index)
625 (define (get-sub-list value master-list)
626 " Get a sub-list whose cadr is equal to @var{value} from @var{master-list}"
627 (if (eq? master-list '())
629 (let ((sublist (car master-list)))
630 (if (equal? (cadr sublist) value)
632 (get-sub-list value (cdr master-list))))))