1 @c -*- coding: utf-8; mode: texinfo; -*-
2 @c This file is part of lilypond-learning.tely
4 Translation of GIT committish: FILL-IN-HEAD-COMMITTISH
6 When revising a translation, copy the HEAD committish of the
7 version that you are working on. See TRANSLATION for details.
16 * Automated engraving::
17 * What symbols to engrave?::
18 * Music representation::
19 * Example applications::
27 The art of music typography is called @emph{(plate) engraving}. The
28 term derives from the traditional process of music printing. Just a
29 few decades ago, sheet music was made by cutting and stamping the
30 music into a zinc or pewter plate in mirror image. The plate would be
31 inked, the depressions caused by the cutting and stamping would hold
32 ink. An image was formed by pressing paper to the plate. The
33 stamping and cutting was completely done by hand. Making a correction
34 was cumbersome, if possible at all, so the engraving had to be perfect
35 in one go. Engraving was a highly specialized skill; a craftsman had
36 to complete around five years of training before earning the title of
37 master engraver, and another five years of experience were
38 necessary to become truly skilled.
40 Nowadays, all newly printed music is produced with computers. This
41 has obvious advantages; prints are cheaper to make, and editorial work
42 can be delivered by email. Unfortunately, the pervasive use of
43 computers has also decreased the graphical quality of scores.
44 Computer printouts have a bland, mechanical look, which makes them
45 unpleasant to play from.
48 @c introduce illustrating aspects of engraving, font...
49 The images below illustrate the difference between traditional
50 engraving and typical computer output, and the third picture shows how
51 LilyPond mimics the traditional look. The left picture shows a scan
52 of a flat symbol from an edition published in 2000. The center
53 depicts a symbol from a hand-engraved Bärenreiter edition of the
54 same music. The left scan illustrates typical flaws of computer
55 print: the staff lines are thin, the weight of the flat symbol matches
56 the light lines and it has a straight layout with sharp corners. By
57 contrast, the Bärenreiter flat has a bold, almost voluptuous
58 rounded look. Our flat symbol is designed after, among others, this
59 one. It is rounded, and its weight harmonizes with the thickness of
60 our staff lines, which are also much thicker than lines in the
63 @multitable @columnfractions .125 .25 .25 .25 .125
67 @image{henle-flat-gray,,4cm}
70 @image{henle-flat-gray,,,png}
75 @image{baer-flat-gray,,4cm}
78 @image{baer-flat-gray,,,png}
83 @image{lily-flat-bw,,4cm}
86 @image{lily-flat-bw,,,png}
90 @c workaround for makeinfo-4.6: line breaks and multi-column cookies
91 @image{henle-flat-bw,,,png} @image{baer-flat-bw,,,png}
92 @image{lily-flat-bw,,,png}
100 LilyPond Feta font (2003)
105 @cindex musical symbols
110 @c introduce illustrating aspects of engraving, spacing...
111 In spacing, the distribution of space should reflect the durations
112 between notes. However, many modern scores adhere to the durations
113 with mathematical precision, which leads to poor results. In the next
114 example a motive is printed twice: once using exact mathematical
115 spacing, and once with corrections. Can you spot which fragment is
118 @cindex optical spacing
119 @c file spacing-optical.
120 @c need to include it here, because we want two images.
141 \override NoteSpacing #'stem-spacing-correction = #0.6
166 \override NoteSpacing #'stem-spacing-correction = #0.0
167 \override NoteSpacing #'same-direction-correction = #0.0
168 \override StaffSpacing #'stem-spacing-correction = #0.0
174 @cindex regular rhythms
175 @cindex regular spacing
177 Each bar in the fragment only uses notes that are played in a constant
178 rhythm. The spacing should reflect that. Unfortunately, the eye
179 deceives us a little; not only does it notice the distance between
180 note heads, it also takes into account the distance between
181 consecutive stems. As a result, the notes of an up-stem/@/down-stem
182 combination should be put farther apart, and the notes of a
183 down-stem/@/up-stem combination should be put closer together, all
184 depending on the combined vertical positions of the notes. The upper
185 two measures are printed with this correction, the lower two measures
186 without, forming down-stem/@/up-stem clumps of notes.
190 Musicians are usually more absorbed with performing than with studying
191 the looks of a piece of music, so nitpicking about typographical
192 details may seem academical. But it is not. In larger pieces with
193 monotonous rhythms, spacing corrections lead to subtle variations in
194 the layout of every line, giving each one a distinct visual signature.
195 Without this signature all lines would look the same, and they become
196 like a labyrinth. If a musician looks away once or has a lapse in
197 concentration, the lines might lose their place on the page.
199 Similarly, the strong visual look of bold symbols on heavy staff lines
200 stands out better when the music is far away from the reader, for
201 example, if it is on a music stand. A careful distribution of white
202 space allows music to be set very tightly without cluttering symbols
203 together. The result minimizes the number of page turns, which is a
206 This is a common characteristic of typography. Layout should be
207 pretty, not only for its own sake, but especially because it helps the
208 reader in her task. For performance material like sheet music, this
209 is of double importance: musicians have a limited amount of attention.
210 The less attention they need for reading, the more they can focus on
211 playing the music. In other words, better typography translates to
214 These examples demonstrate that music typography is an art that is
215 subtle and complex, and that producing it requires considerable
216 expertise, which musicians usually do not have. LilyPond is our
217 effort to bring the graphical excellence of hand-engraved music to the
218 computer age, and make it available to normal musicians. We have
219 tuned our algorithms, font-designs, and program settings to produce
220 prints that match the quality of the old editions we love to see and
226 @node Automated engraving
227 @section Automated engraving
229 How do we go about implementing typography? If craftsmen need over
230 ten years to become true masters, how could we simple hackers ever
231 write a program to take over their jobs?
233 The answer is: we cannot. Typography relies on human judgment of
234 appearance, so people cannot be replaced completely. However, much of
235 the dull work can be automated. If LilyPond solves most of the common
236 situations correctly, this will be a huge improvement over existing
237 software. The remaining cases can be tuned by hand. Over the course
238 of years, the software can be refined to do more and more things
239 automatically, so manual overrides are less and less necessary.
241 When we started, we wrote the LilyPond program entirely in the C++
242 programming language; the program's functionality was set in stone by
243 the developers. That proved to be unsatisfactory for a number of
247 @item When LilyPond makes mistakes,
248 users need to override formatting decisions. Therefore, the user must
249 have access to the formatting engine. Hence, rules and settings cannot
250 be fixed by us at compile-time but must be accessible for users at
253 @item Engraving is a matter of visual judgment, and therefore a matter of
254 taste. As knowledgeable as we are, users can disagree with our
255 personal decisions. Therefore, the definitions of typographical style
256 must also be accessible to the user.
258 @item Finally, we continually refine the formatting algorithms, so we
259 need a flexible approach to rules. The C++ language forces a certain
260 method of grouping rules that do not match well with how music
264 These problems have been addressed by integrating an interpreter for
265 the Scheme programming language and rewriting parts of LilyPond in
266 Scheme. The current formatting architecture is built around the
267 notion of graphical objects, described by Scheme variables and
268 functions. This architecture encompasses formatting rules,
269 typographical style and individual formatting decisions. The user has
270 direct access to most of these controls.
272 Scheme variables control layout decisions. For example, many
273 graphical objects have a direction variable that encodes the choice
274 between up and down (or left and right). Here you see two chords,
275 with accents and arpeggios. In the first chord, the graphical objects
276 have all directions down (or left). The second chord has all
277 directions up (right).
279 @lilypond[quote,ragged-right]
281 \override SpacingSpanner #'spacing-increment = #3
282 \override TimeSignature #'transparent = ##t
284 \stemDown <e g b>4_>-\arpeggio
285 \override Arpeggio #'direction = #RIGHT
286 \stemUp <e g b>4^>-\arpeggio
291 The process of formatting a score consists of reading and writing the
292 variables of graphical objects. Some variables have a preset value. For
293 example, the thickness of many lines -- a characteristic of typographical
294 style -- is a variable with a preset value. You are free to alter this
295 value, giving your score a different typographical impression.
297 @lilypond[quote,ragged-right]
300 c'4-~ c'16 as g f e16 g bes c' des'4
305 \override Beam #'thickness = #0.3
306 \override Stem #'thickness = #0.5
307 \override Bar #'thickness = #3.6
308 \override Tie #'thickness = #2.2
309 \override StaffSymbol #'thickness = #3.0
310 \override Tie #'extra-offset = #'(0 . 0.3)
316 Formatting rules are also preset variables: each object has variables
317 containing procedures. These procedures perform the actual
318 formatting, and by substituting different ones, we can change the
319 appearance of objects. In the following example, the rule which note
320 head objects are used to produce their symbol is changed during the
323 @lilypond[quote,ragged-right]
324 #(set-global-staff-size 30)
326 #(define (mc-squared grob orig current)
327 (let* ((interfaces (ly:grob-interfaces grob))
328 (pos (ly:grob-property grob 'staff-position)))
329 (if (memq 'note-head-interface interfaces)
331 (ly:grob-set-property! grob 'stencil ly:text-interface::print)
332 (ly:grob-set-property! grob 'font-family 'roman)
333 (ly:grob-set-property! grob 'text
334 (make-raise-markup -0.5
336 ((-5) (make-simple-markup "m"))
337 ((-3) (make-simple-markup "c "))
338 ((-2) (make-smaller-markup (make-bold-markup "2")))
339 (else (make-simple-markup "bla")))))))))
341 \new Voice \relative c' {
343 \set autoBeaming = ##f
346 \once \override NoteHead #'stencil = #ly:note-head::brew-ez-stencil
347 \once \override NoteHead #'font-size = #-7
348 \once \override NoteHead #'font-family = #'sans
349 \once \override NoteHead #'font-series = #'bold
351 \once \override NoteHead #'style = #'cross
353 \applyOutput #'Voice #mc-squared
356 { d8[ es-( fis^^ g] fis2-) }
357 \repeat unfold 5 { \applyOutput #'Voice #mc-squared s8 }
364 @node What symbols to engrave?
365 @section What symbols to engrave?
370 The formatting process decides where to place symbols. However, this
371 can only be done once it is decided @emph{what} symbols should be
372 printed, in other words what notation to use.
374 Common music notation is a system of recording music that has evolved
375 over the past 1000 years. The form that is now in common use dates
376 from the early renaissance. Although the basic form (i.e., note heads
377 on a 5-line staff) has not changed, the details still evolve to
378 express the innovations of contemporary notation. Hence, it
379 encompasses some 500 years of music. Its applications range from
380 monophonic melodies to monstrous counterpoints for large orchestras.
382 How can we get a grip on such a many-headed beast, and force it into
383 the confines of a computer program? Our solution is to break up the
384 problem of notation (as opposed to engraving, i.e., typography) into
385 digestible and programmable chunks: every type of symbol is handled by
386 a separate module, a so-called plug-in. Each plug-in is completely
387 modular and independent, so each can be developed and improved
388 separately. Such plug-ins are called @code{engraver}s, by analogy
389 with craftsmen who translate musical ideas to graphic symbols.
391 In the following example, we see how we start out with a plug-in for
392 note heads, the @code{Note_heads_engraver}.
394 @lilypond[quote,ragged-right]
395 \include "engraver-example.ily"
402 \remove "Stem_engraver"
403 \remove "Phrasing_slur_engraver"
404 \remove "Slur_engraver"
405 \remove "Script_engraver"
406 \remove "Beam_engraver"
407 \remove "Auto_beam_engraver"
411 \remove "Accidental_engraver"
412 \remove "Key_engraver"
413 \remove "Clef_engraver"
414 \remove "Bar_engraver"
415 \remove "Time_signature_engraver"
416 \remove "Staff_symbol_engraver"
417 \consists "Pitch_squash_engraver"
424 Then a @code{Staff_symbol_engraver} adds the staff
426 @lilypond[quote,ragged-right]
427 \include "engraver-example.ily"
434 \remove "Stem_engraver"
435 \remove "Phrasing_slur_engraver"
436 \remove "Slur_engraver"
437 \remove "Script_engraver"
438 \remove "Beam_engraver"
439 \remove "Auto_beam_engraver"
443 \remove "Accidental_engraver"
444 \remove "Key_engraver"
445 \remove "Clef_engraver"
446 \remove "Bar_engraver"
447 \consists "Pitch_squash_engraver"
448 \remove "Time_signature_engraver"
455 the @code{Clef_engraver} defines a reference point for the staff
457 @lilypond[quote,ragged-right]
458 \include "engraver-example.ily"
465 \remove "Stem_engraver"
466 \remove "Phrasing_slur_engraver"
467 \remove "Slur_engraver"
468 \remove "Script_engraver"
469 \remove "Beam_engraver"
470 \remove "Auto_beam_engraver"
474 \remove "Accidental_engraver"
475 \remove "Key_engraver"
476 \remove "Bar_engraver"
477 \remove "Time_signature_engraver"
484 and the @code{Stem_engraver} adds stems.
486 @lilypond[quote,ragged-right]
487 \include "engraver-example.ily"
494 \remove "Phrasing_slur_engraver"
495 \remove "Slur_engraver"
496 \remove "Script_engraver"
497 \remove "Beam_engraver"
498 \remove "Auto_beam_engraver"
502 \remove "Accidental_engraver"
503 \remove "Key_engraver"
504 \remove "Bar_engraver"
505 \remove "Time_signature_engraver"
512 The @code{Stem_engraver} is notified of any note head coming along.
513 Every time one (or more, for a chord) note head is seen, a stem
514 object is created and connected to the note head. By adding
515 engravers for beams, slurs, accents, accidentals, bar lines,
516 time signature, and key signature, we get a complete piece of
519 @lilypond[quote,ragged-right]
520 \include "engraver-example.ily"
524 This system works well for monophonic music, but what about
525 polyphony? In polyphonic notation, many voices can share a staff.
527 @lilypond[quote,ragged-right]
528 \include "engraver-example.ily"
529 \new Staff << \topVoice \\ \botVoice >>
532 In this situation, the accidentals and staff are shared, but the stems,
533 slurs, beams, etc., are private to each voice. Hence, engravers should
534 be grouped. The engravers for note heads, stems, slurs, etc., go into a
535 group called @q{Voice context,} while the engravers for key, accidental,
536 bar, etc., go into a group called @q{Staff context.} In the case of
537 polyphony, a single Staff context contains more than one Voice context.
538 Similarly, multiple Staff contexts can be put into a single Score
539 context. The Score context is the top level notation context.
543 Program reference: @internalsref{Contexts}.
545 @lilypond[quote,ragged-right]
546 \include "engraver-example.ily"
549 \new Staff << \topVoice \\ \botVoice >>
550 \new Staff << \pah \\ \hoom >>
555 @node Music representation
556 @section Music representation
558 Ideally, the input format for any high-level formatting system is an
559 abstract description of the content. In this case, that would be the
560 music itself. This poses a formidable problem: how can we define what
561 music really is? Instead of trying to find an answer, we have reversed
562 the question. We write a program capable of producing sheet music,
563 and adjust the format to be as lean as possible. When the format can
564 no longer be trimmed down, by definition we are left with content
565 itself. Our program serves as a formal definition of a music
568 The syntax is also the user-interface for LilyPond, hence it is easy
576 a quarter note C1 (middle C) and an eighth note D1 (D above middle C)
578 @lilypond[quote,fragment]
582 On a microscopic scale, such syntax is easy to use. On a larger
583 scale, syntax also needs structure. How else can you enter complex
584 pieces like symphonies and operas? The structure is formed by the
585 concept of music expressions: by combining small fragments of music
586 into larger ones, more complex music can be expressed. For example
588 @lilypond[quote,verbatim,fragment,relative=1]
593 Chords can be constructed with @code{<<} and @code{>>} enclosing the notes
595 @c < > is not a music expression,
596 @c so we use <<>> iso. <> to drive home the point of
597 @c expressions. Don't change this back --hwn.
602 @lilypond[quote,fragment,relative=1]
603 \new Voice { <<c4 d4 e>> }
607 This expression is put in sequence by enclosing it in curly braces
608 @code{@{@tie{}@dots{}@tie{}@}}
611 @{ f4 <<c4 d4 e4>> @}
614 @lilypond[quote,relative=1,fragment]
619 The above is also an expression, and so it may be combined
620 again with another simultaneous expression (a half note) using <<,
624 << g2 \\ @{ f4 <<c4 d4 e4>> @} >>
627 @lilypond[quote,fragment,relative=2]
628 \new Voice { << g2 \\ { f4 <<c d e>> } >> }
631 Such recursive structures can be specified neatly and formally in a
632 context-free grammar. The parsing code is also generated from this
633 grammar. In other words, the syntax of LilyPond is clearly and
634 unambiguously defined.
636 User-interfaces and syntax are what people see and deal with
637 most. They are partly a matter of taste, and also subject of much
638 discussion. Although discussions on taste do have their merit, they
639 are not very productive. In the larger picture of LilyPond, the
640 importance of input syntax is small: inventing neat syntax is easy, while
641 writing decent formatting code is much harder. This is also
642 illustrated by the line-counts for the respective components: parsing
643 and representation take up less than 10% of the source code.
646 @node Example applications
647 @section Example applications
649 We have written LilyPond as an experiment of how to condense the art
650 of music engraving into a computer program. Thanks to all that hard
651 work, the program can now be used to perform useful tasks. The
652 simplest application is printing notes.
654 @lilypond[quote,relative=1,fragment]
655 \time 2/4 c4 c g'4 g a4 a g2
659 By adding chord names and lyrics we obtain a lead sheet.
661 @lilypond[quote,ragged-right]
663 \chords { c2 c f2 c }
664 \new Staff \relative c' { \time 2/4 c4 c g'4 g a4 a g2 }
665 \new Lyrics \lyricmode { twin4 kle twin kle lit tle star2 }
669 Polyphonic notation and piano music can also be printed. The following
670 example combines some more exotic constructs.
672 @lilypondfile[quote,ragged-right]{screech-boink.ly}
674 The fragments shown above have all been written by hand, but that is
675 not a requirement. Since the formatting engine is mostly automatic, it
676 can serve as an output means for other programs that manipulate
677 music. For example, it can also be used to convert databases of
678 musical fragments to images for use on websites and multimedia
681 This manual also shows an application: the input format is text, and
682 can therefore be easily embedded in other text-based formats such as
683 @LaTeX{}, HTML, or in the case of this manual, Texinfo. By means of a
684 special program, the input fragments can be replaced by music images
685 in the resulting PDF or HTML output files. This makes it easy
686 to mix music and text in documents.
690 @node About this manual
691 @section About this manual
693 There are two manuals about LilyPond: the @emph{user manual} (this
694 document), and @emph{program usage}.
697 @subheading User manual
699 The manual is divided into three books.
701 @subsubheading Learning manual
703 This book explains how to begin learning LilyPond, as well as explaining
704 some key concepts in easy terms. It is recommended to read these
705 chapters in a linear fashion.
714 @emph{@ref{Tutorial}},
715 gives a gentle introduction to typesetting music. First time
716 users should start here.
719 @c @emph{@ref{Putting it all together}},
720 @c explains some general concepts about the lilypond file format. If
721 @c you are not certain where to place a command, read this chapter!
724 @emph{@ref{Working on LilyPond projects}},
725 discusses practical uses of LilyPond and how to avoid some common
729 @emph{@ref{Tweaking output}},
730 shows how to change the default engraving that LilyPond
736 @subsubheading Notation reference
738 This book explains all the LilyPond commands which produce notation. It
739 assumes that readers are familiar with the concepts in the Learning
742 All of this needs to be rewritten after GDP, anyway.
749 @emph{@r ef{Basic notation}},
750 discusses topics grouped by notation construct. This section gives
751 details about basic notation that will be useful in almost any
755 @emph{@r ef{Instrument-specific notation}},
756 discusses topics grouped by notation construct. This section gives
757 details about special notation that will only be useful for particular
758 instrument (or vocal) groups.
761 @emph{@r ef{Advanced notation}},
762 discusses topics grouped by notation construct. This section gives
763 details about complicated or unusual notation.
766 @emph{@r ef{Changing defaults}},
767 explains how to fine tune layout.
770 @emph{@r ef{Non-musical notation}},
771 discusses non-musical output such as titles, multiple movements,
772 and how to select which MIDI instruments to use.
775 @emph{@r ef{Spacing issues}},
776 discusses issues which affect the global output, such as selecting
777 paper size or specifying page breaks.
780 @emph{@r ef{Interfaces for programmers}},
781 explains how to create music functions.
786 @subsubheading Appendices
788 This book contains useful reference charts.
795 @emph{@r ef{Literature list}},
796 contains a set of useful reference books for those who wish to know
797 more on notation and engraving.
801 @emph{@r ef{Scheme tutorial}},
802 presents a short introduction to Scheme, the programming
803 language that music functions use.
806 @emph{@r ef{Notation manual tables}},
807 are a set of tables showing the chord names, MIDI instruments,
808 a list of color names, and the Feta font.
811 @emph{@r ef{Templates}},
812 of LilyPond pieces. Just cut and paste a
813 template into a file, add notes, and you're done!
817 @emph{@r ef{Cheat sheet}},
818 is a handy reference of the most common LilyPond commands.
822 @emph{@r ef{LilyPond command index}},
823 is an index of all LilyPond @code{\commands}.
827 @emph{@r ef{LilyPond index}},
834 @subheading Program usage
836 This book explains how to execute the program and how to integrate
837 LilyPond notation with other programs.
842 @emph{@rprogram{Install}},
843 explains how to install LilyPond (including compilation if desired).
846 @emph{@rprogram{Setup}},
847 describes how to configure your computer for optimum LilyPond usage,
848 such as using special environments for certain text editors.
851 @emph{@rprogram{Running LilyPond}},
852 shows how to run LilyPond and its helper programs. In addition, this
853 section explains how to upgrade input files from previous versions of
857 @emph{@rprogram{LilyPond-book}},
858 explains the details behind creating
859 documents with in-line music examples, like this manual.
862 @emph{@rprogram{Converting from other formats}},
863 explains how to run the conversion programs. These programs are
864 supplied with the LilyPond package, and convert a variety of music
865 formats to the @code{.ly} format.
871 @subsubheading Other information
873 There are a number of other places which may be very valuable.
879 @cindex foreign languages
883 The @ref{Top,Music glossary,,music-glossary}, explains musical terms and
884 includes translations to various languages. It is also available in
888 The music glossary explains musical terms, and includes translations
889 to various languages. It is a separate document, available in HTML
892 If you are not familiar with music notation or music terminology
893 (especially if you are a non-native English speaker), it is highly
894 advisable to consult the glossary.
901 @uref{source/input/lsr/collated-files.html,Snippets}
906 are a great collection of short examples which demonstrate tricks, tips,
907 and special features of LilyPond. Most of these snippets can also be
908 found in the @uref{http://lsr.dsi.unimi.it/,LilyPond Snippet
909 Repository}. This website also has a searchable LilyPond manual.
918 @ref{Top,Program reference,,lilypond-internals}
920 is a set of heavily cross linked HTML pages, which document the
921 nitty-gritty details of each and every LilyPond class, object, and
922 function. It is produced directly from the formatting definitions used.
924 Almost all formatting functionality that is used internally, is
925 available directly to the user. For example, all variables that control
926 thickness values, distances, etc., can be changed in input files. There
927 are a huge number of formatting options, and all of them are described
928 in this document. Each section of the notation manual has a @b{See
929 also} subsection, which refers to the generated documentation. In the
930 HTML document, these subsections have clickable links.
935 Once you are an experienced user, you can use the manual as reference:
936 there is an extensive index@footnote{If you are looking for something,
937 and you cannot find it in the manual, that is considered a bug. In
938 that case, please file a bug report.}, but the document is also
944 @uref{source/Documentation/user/lilypond-big-page.html, one big page},
946 which can be searched easily using the search facility of a web
950 In all HTML documents that have music fragments embedded, the LilyPond
951 input that was used to produce that image can be viewed by clicking
954 The location of the documentation files that are mentioned here can vary
955 from system to system. On occasion, this manual refers to
956 initialization and example files. Throughout this manual, we refer to
957 input files relative to the top-directory of the source archive. For
958 example, @file{input/@/lsr/@/dirname/@/bla@/.ly} may refer to the file
959 @file{lilypond@/2.x.y/@/input/@/lsr/@/dirname/@/bla@/.ly}. On binary
960 packages for the Unix platform, the documentation and examples can
961 typically be found somewhere below
962 @file{/usr/@/share/@/doc/@/lilypond/}. Initialization files, for
963 example @file{scm/@/lily@/.scm}, or @file{ly/@/engraver@/-init@/.ly},
964 are usually found in the directory @file{/usr/@/share/@/lilypond/}.
966 @cindex adjusting output
969 @cindex lilypond-internals
970 @cindex internal documentation
972 @cindex extending lilypond
975 Finally, this and all other manuals, are available online both as PDF
976 files and HTML from the web site, which can be found at
977 @uref{http://@/www@/.lilypond@/.org/}.