release: 1.1.13

[lilypond.git] / Documentation / tex / tutorial.yo

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COMMENT( This document contains Mudela fragments.  You need at least
Yodl-1.30.18 to convert this to tex or html.

TODO

pipethrough(date) sucks.

paragraphs have too much space.

)

COMMENT(
        Mainly written by Han-Wen Nienhuys, 

        with help of (among others)

        * Jan Nieuwenhuizen

        * Lambert Meertens,

        * Adrian Mariano

        * Mats Bengtsson

)

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article(Mudela -- Using LilyPond to typeset music)
      (Han-Wen Nienhuys and Jan Nieuwenhuizen)
      (nop()PIPETHROUGH(date "+%B %d, %Y")()()nop())


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sect(Introduction)
label(tutorial:introduction)
latexcommand(\parindent2pc)
  
If you are reading this, you probably are interested in printing
music.  LilyPond is a program that can print music from a
specification that you, the user, supply.  Using LilyPond may be a bit
quaint in the beginning, because you have to give that specification
using a em(language).  This document is a gentle introduction to that
language, which is called Mudela, an abbreviation for Music Definition
Language.

We will demonstrate the working of Mudela by presenting  examples of
input alongside with the resulting output.  We will comment on these
examples using English terms for notation, so if you are not familiar
with these terms, you should consult the glossary that is distributed
with LilyPond: it contains a list of musical terms along with
explanations and translations in some other languages.

sect(The first tune)
label(sec:firsttune)

To demonstrate what LilyPond input looks like, we start off with a
full fledged, yet simple, example. It is somewhat convoluted version
of one of the menuets in bind(J.)bind(S.)Bach's em(Clavierbuchlein).

mudela(verbatim)(
% lines preceded by a percent are comments.
\include "paper16.ly"
\score {
    \notes                      
    \relative c'' {             
        \key g;
        \time 3/4;              

        d4 [g,8 a b c] d4 g, g |
        e'4 [c8 d e fis] g4 g, g |
        c4 [d8( )c b a( ] )b4 [c8 b a g] |
        a4 [b8 a g fis] g2.  |

        \bar ":|";              

        b'4 [g8 a b g]
        a4 [d,8 e fis d] |
        g4 [e8 fis g d] cis4 [b8 cis] a4 |
        [a8-. b-. cis-. d-. e-. fis-. ] 
        g4 fis e |
        fis a,  r8 cis8
        d2.-\fermata
        \bar "|.";
    }
    \paper {
       linewidth = 14.0 \cm; % standard settings are too wide for a book
   }
})

Before we will discuss the contents of the above, it would be best if
you would try to enter and save this text with a text editor, compile
it with LilyPond and view the output.  Details of this procedure may
vary from system to system.  On a Unix system, you should enter the
input in a file ending in file(.ly), such as file(menuet.ly).  To
create the output, one would issue code(ly2dvi menuet).

file(ly2dvi) is a little program that does the job of calling the
LilyPond and TeX() and adjusting page margins.

If all goes well, this will create the output file file(menuet.dvi).
To view this output, issue the command code(xdvi menuet).  Now that we
are familiar with the procedure to view the output, we will analyse
the input itself, line by line.

verb(% lines preceded by a percent are comments.)COMMENT(

)The percent sign (code(%)) introduces a line comment.  If you want
make larger comments, you can use block comments. These are delimited
by code(%{) and code(%})


verb(\input "paper16.ly")

By default, LilyPond will use definitions for a staff of 20 point
high.  If you want smaller output (e.g., 16 point), you have to import
the setting for that size.  You can do this by including a file.
code(\include "file") is replaced by the contents of  code(file).


verb(\score {
) COMMENT( 

) A mudela file combines music with directions for outputting that
music.  The music is combined with the output directions by putting
them into a code(\score) block.
verb(
   \notes               
) COMMENT( 

)This makes LilyPond ready for accepting notes.
verb(
    \relative c''
)COMMENT(

) As we will see, pitches are combinations of octave, note name and
chromatic alteration.  In this scheme, the octave is indicated by
using raised quotes (`code (')') and ``lowered'' quotes (commas:
`code(,)').  The central C is denoted by code(c').  The C one octave
higher is code(c'').  One and two octaves below central C is denoted
by code(c) and code(c,) respectively.

If you have to indicate the pitches in a long piece that is written in
either a high or very low octave, you would have to type very many
quotes.  To remedy this, LilyPond has a so-called "relative" octave
entry mode.  In this mode, notes without quotes are chosen in such an
octave that they are the closest to the preceding note.  If you add a
high-quote an extra octave is added.  The lowered quote will substract
an octave.  Because the first note obviously has no predecessor, you
have to give the (absolute) pitch of the note to start with.
COMMENT(

)verb(
       {                          % sequential music follows
)COMMENT(

) The brace indicates that what follows is sequential music, i.e.,
notes that are to be played and printed after each other.  This is in
contrast with simultaneous music: notes that are to be played like a
chord.  You should be careful not to confuse this brace with the one
coming after code(\score).


verb(
        \time 3/4;              % set the time signature.
) COMMENT(

) This command changes the time signature of the current piece: this
prints a 3/4 sign.  The 3/4 value is also used to generate bar lines
in the right spots.
verb(
        \key g;
) COMMENT(

) This command changes the current key to G-major.  Although
this command comes after the code(\time) command, in the
output, the key comes before the time signature: LilyPond knows about
music typesetting conventions.
verb(
        d4
) COMMENT(

) This is a code(d) note.  The relative music was started with a
code(c''), the real pitch of this note is code(d'').  The 4 
designates the duration of the note (it is a quarter note). COMMENT(

)verb(
        [g,8
)COMMENT(

)The open bracket starts a beam.  This bracket is connected to the
following note, which is an eighth with pitch code(g') (remember
relative mode for pitches!)
COMMENT(

)verb(
        a b
)COMMENT(

)These are notes with pitch code(a') and code(b').  Because their
duration is the same as the code(g), there is no need to enter the
duration (It is not illegal to enter it anyway.  Then you would have
to enter code(a8 b8))
COMMENT(

)verb(
          c]
) COMMENT(

) This ends the beam started four notes earlier, at the code(g).  In
the output, you will notice a measure bar following this note.  You do
not have to enter anything to make LilyPond create a bar.  Instead
Lily will deduce where bars have to be by comparing durations of notes with
the current time signature.  COMMENT(

)verb(
          d4 g, g |
) COMMENT(

) Three more notes:  The code(|) is a "barcheck".  When processing the
music, LilyPond will check  that barchecks are found at the start of
a bar precisely.  This makes it easy to spot where notes are forgotten. 
verb(
        e'4 [c8 d e fis]
) COMMENT(

) So far, no notes were chromatically altered.  Here is the first one
that is: code(fis). Mudela by default uses Dutch note names, and
``Fis'' is the Dutch note name for ``F sharp''.  However, there is no
sharp sign in the output. The program keeps track of key signatures,
and will only print accidentals if they are needed.
verb(
        c4 [d8( )c b a( ] )b4 [c8 b a g] |
) COMMENT(

) The next line shows something new: a slur is a symbol that is
printed over several notes.  In mudela, one enters a slur by marking
the beginning and ending note of the slur with an opening and closing
parenthesis respectively.  In the line shown above this is done for
two slurs.  Note that parentheses (slur markers) are between the
notes, and the brackets (beam markers) around the notes. As you can
see, the brackets and parentheses do not have to nest.

verb(
        a4 [b8 a g fis] g2.  |
) COMMENT(

) A duration that is to be augmented with a duration dot, is notated
with a duration number followed by periods, as many as you want
augmentation dots.COMMENT(

)verb(
        \bar ":|";              % a repeat sign
) COMMENT(

)
Lily can not detect where you want your music to be repeated, so you
have to instruct her: a special bar symbol can be entered by the
code(\bar) command followed by a string that signifies the bar symbol
that you want.  Then comes a semicolon to separate the string from the
rest of the notes, analogously with code(\key) and code(\time).
verb(
     cis'4 [b8 cis] a4 |
) COMMENT(

)
This line shows that Lily will print an accidental if that is needed:
the first C sharp will be printed with an accidental, the second without.
verb(
        [a8-. b-. cis-. d-. e-. fis-. ] % try some super and subscripts.
) COMMENT(

)
There is more to music than just pitches and rhythms.  An important
aspect is articulation.  You can enter articulation signs either in an
abbreviated form, by a dash and the the character for the
articulation to use,  e.g. code(-.) for staccato as shown above.
COMMENT(

)verb(
        fis a,  r8 cis8
) COMMENT(

)
Rests are denoted by the special notename code(r).  You can also make
an invisible rest by using the special notename code(s).
verb(
        d2.-\fermata
) COMMENT(

) Finally, all articulations have a verbose form, like code(\fermata).
The ``command'' COMMENT(Hi Adrian :-) code(\fermata) is not part of
the core of the language (most of the other discussed elements are),
but it is an abbreviation of a more complicated description of a
fermata.  code(\fermata) refers to that abbreviation and is therefore
called an em(identifier).

verb(
        }
) COMMENT(

)
This ends the sequential music.

verb(\paper {
            linewidth = 10.0\cm;
})
This specifies a conversion from music to notation output.  Most of
the details of this conversions (font sizes, dimensions, etc.) have
been taken care of, but  to fit the output  in this document, it has
to be smaller.  We do this by setting the line width to 10 centimeter
(approximately 4 inches).

verb(
        }
)
Finally, the last brace ends the code(\score) block.



There are a couple of things to note here.  The input format tries to
capture the meaning of em(music), and not notation.  Therefore the
format contains musical concepts like pitches and durations, instead
of symbols and positions.  Second, the format tries to be
em(context-free): a note will sound the same regardless of the current
time signature, the key nop(etc.)

The purpose of LilyPond informally is explained by the term `music
typesetter'. As you may have figured out by now, this is not a really
adequate name: not only does the program print musical symbols, it
also tries to make esthetic decisions, and it also em(generates) both
the symbols and the decisions from a high-level musical description.
In other words, the function of LilyPond would be best described by
`music compiler' or `music to notation compiler'.

We find that ---once you master the language--- there are big
advantages of using LilyPond over GUI oriented programs: first,
entering music is quite efficient.  Second, it is possible to explain
exactly what the meaning piece of mudela is, and you can transform
these pieces automatically (eg, by transposing them).  Third, the
program that is not interactive, so much less tradeoffs have to be
made between processing speed and the beauty of the output: you get
prettier output by using LilyPond.


As you can see, the most interesting part of the input is music
itself, in this case the sequence of notes.  We will therefore focus
on entering music for now.  Consequently, when we mean
verb(\score {
        \notes { XXXX } 
        \paper {  }
})COMMENT(

) we will leave out the the repetitive details for now and just print
code(XXXX).



sect(When you know the notes to nop(print)ellipsis())

The basic building block of music is the note.  We lightly touched
notes in the previous example.  Here comes the full explanation A note
is made of a pitch and a duration.  The pitch of the central C is
written as code(c').  This is in line with musicological notation;
there this pitch is transcribed as nop(c)sups(1) or c'.  A
quarter-note duration is written as code(4).  So, to print a quarter
note whose pitch is central C, you enter the following code(c'4).

subsect(Duration)

The duration of a note is specified as a number: a whole note is
denoted by 1, a half note by 2, a quarter by 4, and so on.  If you
want to augment a duration with a dot, simply affix a period to the
number.  You can also print notes longer than a whole.  You do this by
using identifiers (code(\breve) and code(\longa):
Here are some random notes to show how it works.

verb(
  c'\longa c'\breve  
  c'1 c'2 c'4 c'8 c'16 c'32 c'64 c'64 c'2. c'8. c'16
)

mudela()(
\score {
       \notes {
         c'\longa c'\breve  
         c'1 c'2 c'4 c'8 c'16 c'32 c'64 c'64 c'2. c'8. c'16
         }
         \paper {
                linewidth = -1.0;
                \translator { \type "Score_engraver";
                            \name "Score";
                            \consists "Note_heads_engraver";
                            \consists "Stem_engraver";
                            \consists "Rhythmic_column_engraver";
         }}}
         
)

subsect(Basic pitches)

The pitch code(c')  consists of two parts: one part for the
note name, and one for the octave.  The letter specifies which note
name to use: note names simply are the letters code(a) to code(g).
The number of apostrophes specifies the octave to use: the central C
is denoted by code(c').footnote(By convention, the A above central C
at concert pitch is the tone that is used to tune instruments.  Its
frequency is about 440 Hz.)  The C which is an eighth higher (the C in
the ``two-line octave'') is denoted by code(c''): every octave adds a
quote.  A note name without quotes designates the pitch below code(c')
(the C in the ``small octave''). If you want to go down even further,
commas should be added, e.g., the C in the ``contra octave'' is
expressed as code(c,,).footnote(The comma is meant to represent a
sunken apostrophe.)

This example demonstrates pitches
mudela(fragment,verbatim,center)(
   c,,4 c, c c' c'' c''' d'4 e'4 f'4 g'4
)


subsect(Alterations)

We have so far ignored chromatically altered pitches.  The names `a'
to `g' for entering pitches are convenient: they are short,
pronounceable and they resemble the words for pitches in normal
musical vocabulary.

Enter flats and sharps.  In English there is no standard terse word
for C sharp or C flat.  For this reason, mudela uses a different,
non-English convention for entering altered pitches: a note is made
sharp by adding the suffix `--is' to its name, and flat by adding the
suffix `--es'.  For a double sharp another `--is' suffix is added, for
flats another `--es' nop(suffix.)  footnote(Variations on this
convention are used in a number of germanic languages, notably Dutch,
German, Swedish, and Norwegian.) The names for the alterations of C
are given in bind(Table)ref(notename-tab).

latexcommand(\begin{table}[h])
  center(
    table(2)(ll)(
      row(cell(english)cell(LilyPond))
      rowline()
      row(cell(c double flat)cell(ceses))
      row(cell(c flat)cell(ces))
      row(cell(c natural)cell(c))
      row(cell(c sharp)cell(cis))
      row(cell(c double sharp)cell(cisis))
    )
  )
  latexcommand(\caption{Default note names})
  label(notename-tab)
latexcommand(\end{table})

Throughout this document we will continue to use these names.footnote(
  Mudela defaults to Dutch notenames.  To make (Dutch) pronunciation
  easier, the a-flat and e-flat are contracted to code(as) and
  code(es).  Similarly, the a double flat and e double flat are
  contracted to code(ases) and code(eses).  For consistency, the dutch
  names also include code(aes), code(aeses), code(ees) and
  code(eeses)) 

If you are not comfortable with these names, you can make your own.
Note names for different languages are included with the example
initialisation files, amongst others English (C sharp is abbreviated
to code(cs)), Italian, Swedish and Norwegian.  If you want to use
these names, issue code(\include "LANGUAGE.ly") where you could
substitute code(italiano), code(deutsch) etc.  for LANGUAGE.  You
should include these files at toplevel, i.e., before opening a
code(\score) block.


sect(Chords)

The previous examples all notes   that were to be played sequentially,  one
note following the other.  You can also use LilyPond to typeset
chords.  You do this  by expressing in mudela simultaneous music,
i.e.,   notes that are to be played concurrently. 

In Mudela you can form simultaneous music by enclosing notes in
pointed parentheses, bind(i.e.)bind(langle())bind(and)rangle().  ASCII
doesn't really have these delimiters, so Mudela uses the larger-than
(code(>)) and smaller-than (code(<)) signs instead.  For example, a
D-major chord is expressed as
mudela(fragment,verbatim,center)(
  <d'8  fis'8 a'8 d''8>
)

Chords can be entered in the music in the same places that notes
can.  As an example we give a snippet of ``Twinkle Twinkle Little
Star'' in chords.  The chords may seem slightly unconventional, but
they only serve to show how chords work.  We've aligned the chords in
the input on their starting beat just to help you reading it.  This
layout does not influence the typesetting result in any way.

mudela(verbatim, fragment)(
  \relative c' {
  \time 2/4;
  c4       c            <c g'>    <c e g>
  <c e a>  <b d a'>     <b2 d g>
  <a4 d f> <bes d f>    <bes c e> <g c e>
  <e a d>  <a, g' cis'> <d2 f d'>
  }
)

There is one thing to note, in sequences of chords, the (relative)
pitch of a is taken with reference to the first note of the previous
chord.

You can nest simultaneous and sequential music in any way you want,
e.g., COMMENT(

)mudela(verbatim,fragment,center)(
        < { g''4 g''4 }
          { c'8 <c' e'> c' <c' e'> } >
)COMMENT(

)
As you can see, LilyPond has some difficulty typesetting this
elegantly.  To adequately solve this, you have to persuade LilyPond to
make separate stems for both sequential music lists.   This is a topic
that is covered in bind(Section)ref(sec:polyphonic).

[Chords and relative mode]


sect(Adding nuances: articulation and dynamics)

Having just chords and notes does not give you real music.  Real music
has more liveliness to it: music can have articulation, dynamics
(louder and softer), etc.  This liveliness has notation, so LilyPond
can print it.  We'll start out by explaining how to obtain the
smallest grains of nuance: the articulation of a single note.  Articulation
is entered by writing a dash and the name of the desired articulation
mark.  You have to add a backslash in front of the name to distinguish
it from the name of a note. COMMENT(

)mudela(fragment,verbatim)(
  c''4-\staccato
  c''4-\tenuto )COMMENT(

) Typing a lot of staccato notes in this syntax will get tedious very
quickly.  Therefore, Mudela has some handy abbreviations for
articulation marks such as staccato and tenuto.  They are shown in the
following example: COMMENT(

)mudela()(
\score{ <
        \property Score.textstyle = typewriter
        \type Staff \notes {
                c''4-.
                c''4--
                c''4-+
                c''4-|
                c''4->
                c''4-^
                }
        \type Lyrics\lyrics {
              "."4 "-" "+" "|" ">" "\^{ }" }
        >
        \paper { linewidth = 12.\cm; }
})COMMENT(

)Text and digits for fingering can be entered in the same manner: add a
dash and the text or digit to be printed:
COMMENT(

)mudela(fragment,verbatim)(c''4-1 g''4-5 c''-"Sul tasto" )
COMMENT(Currently, the meaning of the
syntax `note-dash-digit/articulation/text' is just ``add a superscript to this
note.''  This is not in line with our goal to em (define) music with
Mudela.  We hope that this will be fixed in a future version of the
language.  In the meantime you can abuse this: the super- and
subscripts can be forced into up or down position respectively by entering an
a caret (code(^)) or an underscore, code (_) instead of the dash:
mudela (fragment,verbatim,center) (
  c'4-^ c'4^^ c'''4-^ c'''4_^
))

Dynamic markings are another way to add a nuance to a note.  They are
entered by adding the name for the dynamic sign after the note.  You
should not enter a dash between the name and the note.footnote(This
  is inconsistent.  We hope that this will be fixed in a later
  version of the language.)COMMENT(

)mudela(verbatim,fragment)(
  c4 \ff c4 \fp c4 c4 \ppp c4 c4 \sfz
)COMMENT(
UGH

)

sect(Bridging the notes: beams, slurs and ties)

Music typesetting does not use fixed symbols only.  A lot of symbols
are variable: they run from one note to another. In LilyPond
terminology, such a symbol is called a em(spanner).  To print a
spanner, you have to attach a marker to the note that begins it and to
the one that ends it.  These are the spanners that are entered like
this:

description(
dit(The slur)
 The slur has the opening parenthesis as 
start marker is.  The stopping marker is the closing parenthesis.
For example:
mudela(fragment,center,verbatim)( c'4( )c'4 )

  The slur is quite flexible: you can nest nop(slurs,)footnote(This is
inconsistent when compared to the syntax for articulation hints.  This
will be fixed some time, we hope.) and you can connect a note with a
slur on both the left and the right side:

mudela(fragment,verbatim,center)(
  c'4((   )c''4 )c'4( )g'4 
)

dit(Beam)

Another spanner is the beam.  The starting marker is the opening
bracket, then ending marker is the closing bracket.  The brackets have
to be em(around) the beamed notes.  footnote(Strictly speaking, a
beam is not a musical concept: beaming doesn't change the meaning of
music, it only clarifies the rhythmic structure.  One might argue that
beams should not be present in a ``music'' language.  Unfortunately,
LilyPond is not smart enough to insert beams into music on its own.

LilyPond does have code that guesses what the pattern should look
like, so that you don't have to specify the beaming for complicated
patterns.  Alas, the algorithm used is not foolproof
yet: code([c8. c32 c32]) will produce incorrect results.)

mudela(fragment,verbatim)(
[c'8 c'] [c'16 c' c' c'] [c'16. c'32 c' c'16.]
)

dit(The tie) The tie is similar to the slur: it  looks like a
slur, but a slur connects whole chords, whereas the tie connects note
heads.  Tied notes should be played as one long note.  In analogy with
TeX()'s tie (which ties together words with a space), LilyPond's tie
is entered as a tilde, `code(~)'.

The input convention for the tilde is somewhat peculiar when used in
conjunction with chords.  Internally, the extra information that is
represented by the tilde has to be attached to a note (or to a rest,
for that matter).  For this reason, you can't put the tilde between
two chords (as in code( <c' g'> ~ <c' g'>)).  The tilde sign must be
directly after a note of the chords.  It does not matter which
one. The following example demonstrates the use of ties:
mudela(fragment,verbatim,center)(
  c''1 ~ c''4
  <c'2. ~  g' es''> <c'4 g' es''> 
)

dit(Hairpins)
Crescendi and decrescendi can be printed in hairpin style.  The
starting marker for the crescendo is code(\<), and for the decrescendo
code(\>).  Both have code(\!) as the ending marker.
mudela(fragment, verbatim)(
   \relative c'' { c4 \< \! c4 \> \! c2
      < c1
        { s4 \< \! s4 \> \! s2 } > }
)
This example shows a trick: by attaching the markings to space rests
that run parallel to the whole note, you can have dynamic markings
within a note. 

)

It is your job to make sure that each spanner that you start, also
ends.  If it doesn't, then Bad Things are likely to happen. If you end
spanners that are not started, LilyPond will warn you about illegal
ending markers.

sect(Commands)
label(sec:commands)

We have focused on printing notes. Notation contains many other
constructs, constructs that help you with reading those notes.
Examples of such constructs are clefs, time signatures, keys etc.
LilyPond will try to generate these constructs as much as possible,
but not all such hints can be inserted automatically, and you can also
override some of the settings.  This can be done by inserting various
commands between the music.  The general form of these commands is
COMMENT(

)center(code(\keyword argument argument ... ;))

These are the commands that are currently supported:
description(
dit(code(\bar) var(bartype))
  This command makes LilyPond print special bar
  lines and repeat symbols.  You can also use it to allow line breaks
  when entering cadenzas.  The argument var(bartype) is a string that
  describes what kind of bar line to print.

mudela(fragment,verbatim)(
    \bar "|:"; c'4 \bar ":|:";    c'4  \bar ":|";  c'4 \bar "||";
    c'4 \bar "empty"; c'4 \bar "|.";
)

  The command `code(\bar "empty")' does not create any visible bar
  line, but it tells LilyPond to allow a linebreak at that
  position.  The `code(\bar)' command prints the specified symbol
  immediately.  If you give a `code(\bar)' command at the end of a
  measure then the specified symbol replaces the automatic bar line;
  otherwise the specified symbol appears in the middle of the measure.
  The code(\bar) command does not affect metric structure.

dit(code(\cadenza) var(togglevalue)) This command toggles the
automatic printing of barlines.  `code(\cadenza 1)' turns off the
automatically generated bar lines.  They are switched on again with
`code(\cadenza 0)'. Then a bar line is printed, and LilyPond will act
as if you are again at the start of a measure.


This is useful when typesetting music without a meter (such as an ad
 libitum cadenza).

dit(code(\clef) var(clefname)) This command sets the current clef for notation,
  i.e., a clef symbol is printed and the notes following this command
  are shifted vertically.  The argument is a string, the name of the
  new clef. The default clef is the treble clef.
  mudela(fragment,verbatim)(
    \clef "bass"; c'4
    \clef "treble"; c'4
    \clef "alto"; c'4    
  )

dit(code(\key) var(pitch) var(type)) This command changes the current
  key signature.  The key signature is printed at the start of every
  line. The var(type) argument is set to code(\major) or code(\minor)
  to get major or minor keys, respectively. Omitting the second
  argument gives major keys. The key of C-minor can thus be specified
  as `code(\key es)' or `code(\key \c minor)'. 
  
dit(code(\keysignature) var(pitchlist))

This command changes the current key signature.  Unlike the
`code(\key)' command, this command can produce arbitrary key
signatures, which can be useful for unconventional keys or modes.  The
key signature is given in the form of a list of notes.  The notes will
be printed in the key signature in the order that they appear on the
list.  For example, the key of C-minor can be specified as
`code(\keysignature bes es as)'.  The command `code(\keysignature fis
es bis)' provides a more exotic example.


dit(code(\time) var(numerator)code(/)var(denominator))
  This command changes the current time signature.
  The default value for this time signature is common time (4/4).

dit(code(\partial) var(duration))
  This command allows you to make
  upsteps at the start of a piece.
  The var(duration) argument has the same form as the duration of a
  note.

The `code(\partial)' command cannot be used to generate partial
measures in the middle of the music.  
Example:
  mudela(fragment,verbatim)(
    \time 4/4;
    \partial 4;
    [d'8 dis'] e' c''4 e'8 c''4 
  )

dit(code(\grouping) var(durationslist)) sets the metric structure of the measure.
    Its effect can best be shown by an example:
    mudela(fragment,verbatim)(
        \time 5/16;
        \grouping 16*3 16*2;
        [c'8 c'16 c'8]
        \grouping 16*2 16*3;
        [c'8 c'16 c'8]
        \grouping 16*5 ;
        [c'8 c'16 c'8]
    )

In practice, you won't be needing this command very often: the
grouping is switched automatically when you issue a code(\time)
command.  It is set to a combination of groups
of 2 and 3 beats, with as many groups of
3 as possible (in other words: 4/4 is divided in two times two beats
(2+2), 8/8 in 3+3+2)
)

The commands described above aren't really music, but they can best be
thought as as notes with no duration.  Since they are grammatically
equivalent to notes, these commands can be used in the same places as
notes:

sect(Notation context)

COMMENT(This section is about translation contexts, a topic of LilyPond that
is somewhat advanced.  You don't have to understand this to use
LilyPond to print simple music.  If you don't want to typeset fancy
polyphonic music or tweak the LilyPond notation engine, you can skip
the next two sections.)

In bind(Section)ref(tutorial:more-staffs) it was explained that there
are more ways to notate a simple chord: as a single voice on a single
staff or in multiple staffs (and we'll soon see, that you can typeset
it as multiple voices on a staff).  Obviously the concept of staff is
not really something musical.  But what is it then?

The most simplistic explanation is: a staff is a graphic peculiarity
of the notation system.  In other words, a staff is a graphic device,
a special picture of five lines on which one can print note heads.  We
will call this view on the concept of staff `staff symbol' from now
on.

But 
there is more to a staff than just the symbol.  A staff
contains---besides a staff symbol--- some more components:
itemize(
it()A staff can have a key signature (printed at the left)
it()A staff can have a time signature (printed at the left)
it()A staff has bar lines
it()A staff has a clef (printed at the left)
) COMMENT(

)
To explain what a staff really is, we'll try to print music without
these components.   Without those, it is still
possible to print music:
mudela()(\score{
\notes \relative c' {  \time 2/4; g'4 c,4 a'4 f4 e c d2 }
\paper { 
  linewidth = -1.;
  \translator {
  \StaffContext
  \remove "Time_signature_engraver";
  \remove "Bar_engraver";
  \remove "Staff_symbol_engraver";
  \remove "Clef_engraver";
  \remove "Key_engraver";
  }
 }
})COMMENT(

) As you can see, you can still make out the general form of the
melody and the rhythm that is to be played, but the notation is
difficult to read.  Moreover, the musical information is not complete.
The stress pattern in the notes can't be deduced from this output.
For this, we need a time signature:

mudela()(
\score {
  \notes \relative c' {  \time 2/4; g'4 c,4 a'4 f4 e c d2 }
  \paper{
  linewidth = -1.;
\translator{
  \StaffContext
  \remove "Bar_engraver";
  \remove "Staff_symbol_engraver";
  \remove "Clef_engraver";
  \remove "Key_engraver";
  }}
 }) COMMENT(

)Technically speaking you know where the strong and weak beats are, but
it is difficult to find them quickly.   Bar lines  help you in finding
the location  of the notes within the measure:
mudela()(
\score {
  \notes \relative c' {  \time 2/4; g'4 c,4 a'4 f4 e c d2 }
  \paper{
  linewidth = -1.;
\translator{
  \StaffContext
  \remove "Staff_symbol_engraver";
  \remove "Clef_engraver";
  \remove "Key_engraver";}
  }
 }
)

We can remedy part of the difficulties with reading pitches by adding a staff
symbol:

mudela()(\score{
  \notes\relative c' { \time 2/4; g'4 c,4
a'4 f4 e c d2 } \paper {
  linewidth = -1.;
  \translator {
  \StaffContext

  \remove "Clef_engraver";
  \remove "Key_engraver";
  }
 }
})COMMENT(

)
This makes the output decidedly easier to read, but you still don't
know what the pitches of the notes above are.  So this is still not
enough.  But suppose you see the following notation:
mudela()(\score {
  \notes \relative c' {\clef alto;  \time 2/4; g'4 c,4 a'4 f4 e c d2 }
  \paper {
    linewidth = -1.;
  }
})COMMENT(

) Now you know the pitch of the notes: you look at the start of the line
and see a clef, with this clef, you can determine the notated pitches.
You have found the em(context) in which the notation is to be
interpreted!

So the context determines the relationship between a piece of music
and its notation: you, the reader, use context to deduce music from
notation.  Because LilyPond is a notation writer instead of a reader,
context works the other way around for Lily: with context a piece of
music can be converted to notation.

We see that a staff forms context, and that context is needed to
convert between notation and music.  In LilyPond we turn around this
reasoning: LilyPond has a notion of notation context, and the staff is
just one example of a notation context.  In fact, the arguments of the
code(\type) command (Staff, GrandStaff) were all names of different
contexts.

We make one final observation before listing the standard notation
contexts.  A score can contain many staffs; A staff can contain many
voices.  This suggests that notation contexts are objects that can be
nested.

The following is a list of the contexts that are supported by
LilyPond.  Each notation context is characterised by its name, the
notation elements it creates, and the contexts that it can contain.
description(
dit(Voice) The code(Voice) context is a context that corresponds to a
  voice on a staff.  This context handles the conversion of noteheads,
  dynamic signs, stems, beams, super- and subscripts, slurs, ties and rests

dit(Staff) The code(Staff) context handles clefs, bar lines, keys,
  accidentals.  A code(Staff) context can contain code(Voice)
  contexts.

dit(RhythmicStaff) The code(RhythmicStaff) context is like the staff,
  but much simpler: the notes are printed on one line, and pitches are
  ignored.  code(RhythmicStaff) can contain code(Voice) contexts.

dit(GrandStaff) A code(GrandStaff) context contains code(Staff)
  contexts, and it adds a brace to the output at the
  nop(left.)footnote(This is a major deficiency in the current
  implementation.  Currently stems, slurs and beams cannot be printed
  across two staffs.  In reality, a grand staff is a hybrid of one big
  staff and two stacked staffs.)
  
  A code(GrandStaff) context can contain 
  code(Staff)s. Typically, it will contain two code(Staff)s, one
  treble staff, and one bass staff. The bar lines of the contained
  staffs are connected vertically.

dit(StaffGroup) A code(StaffGroup) context contains code(Staff) or
  code(Lyrics) contexts, and prints a bracket at the left.  The bar
  lines in the participating staffs are connected.

dit(Lyrics) As its name suggests, The code(Lyrics) context deals with
  typesetting lyrics.  This topic will be covered in
  bind(Section)ref(tutorial:lyrics).
  
dit(Score) The code(Score) context is the toplevel context: no context can
  contain a code(Score) context.  The code(Score) context handles the
  administration of time signatures.  It also makes sure that items
  such as clefs, time signatures, and key-signatures are aligned across staffs.
  
  The code(Score) can contain code(Staff), code(StaffGroup),
  code(Lyrics), code(GrandStaff) and code(RhythmicStaff) contexts.

COMMENT(do ChoireStaff)
)


If you are familiar with structured documents, you might see the
analogy of a context with a stylesheet: a stylesheet is neither
presentation nor information, but rather a recipe em(how) a specific
piece of information should be presented.  The big difference with
stylesheets is that in music notation the elements provided by context
are essential to understanding what is notated.

The notions of ``current clef'' and ``current position within the
measure'' are all properties of notation contexts.  Commands like
code(\clef) and code(\cadenza) change these properties, and this
explains why they are fundamentally different from musical expressions
like notes and rests.

A notation context is not a primitive element of LilyPond, but rather
  Later on, in bind(Section)ref(tutorial:engravers) we will explain
  how you can create your own contexts.


sect(Nested music: multiple staffs)
label(tutorial:more-staffs)

Now we explain how to typeset music that runs in multiple staffs.
Consider the following---somewhat unrealistic---example:

mudela(fragment)(
 \type GrandStaff <e'4 {\clef bass; g4^""} >
)

In this example the music consists of two notes.  The above would
sound the same if it were written as a single chord on a single staff,
i.e., COMMENT(

)mudela(fragment)(
        <g4 e'4>
)COMMENT(

) The Mudela construct for multiple staffs reflects the similarity
between the two examples: to get multiple staffs in Mudela you enter a
chord, with an additional instruction to tell LilyPond that the chord
does not represent notes stacked together, but staffs stacked
together.

If a piece of music is to be interpreted as a staff, then this can be
expressed with the code(\type) construct.  The following input says
``the quarter note with pitch e should be put on a staff.''

verb(
  \type Staff e'4 
)COMMENT(

) The same can be done for the other note, i.e.,

verb(
  \type Staff g4 
) COMMENT(

) If you want to stack these staffs, you must create a chord of both:

verb(
  < \type Staff e'4
    \type Staff g4 
  >
)

This looks reasonable, but the effect of this input is not what you
might expect:
mudela(fragment)(
  < \type Staff e'4
    \type Staff g4 
  >
)COMMENT(

) Since there are no names specified for the desired staffs, LilyPond
thinks your wishes are fullfilled by putting the code(g) on the same
staff as the code(e).  The correct solution is to label both staffs
with different names, for example code(trebleStaff) and
code(bassStaff).  This makes LilyPond distinguish between them, and
create two staffs:

mudela(verbatim,fragment)(
  < \type Staff = trebleStaff e'4
    \type Staff = bassStaff  g4 
  >
)COMMENT(

) The names that you choose do not matter just as long as they are
different.  This is almost right, except for the brace at the left and
the clef of the second staff.  If you want a brace, then you have to
tell LilyPond that the chord you just formed is to be interpreted as a
so-called grand staff.  This is also done with the code(\type)
command.  The bass clef is made with a clef command:  COMMENT(

) mudela(verbatim,fragment)(
  \type GrandStaff <
        \type Staff = treblestaff e'4
        \type Staff = bassstaff { \clef "bass"; g4 }
  >)COMMENT(

)

sect(Polyphonic music (or: Notation context properties))
label(sec:polyphonic)

In the section on notation contexts we explained that a notation
context can have properties that influence the conversion from music
to notation.  A simple example of such a property is the clef: the
type of a clef helps determines the vertical position of note heads in
a staff.  Some of these properties can be modified by commands such as
code(\clef) and code(\time).  But there is more: notation contexts
also have properties are settable in a generic fashion.  We will
demonstrate this feature by printing multiple voices on a staff.

Printing more than one voice on a staff, is not unlike printing
multiple   staffs stacked together.  This suggests that  the template
to follow  is this:
verb(
  \type Staff <
    \type Voice = one  ...
    \type Voice = two  ...
  >
) COMMENT(

) On the ellipsis there should be music going from left to right, in
other words, notes enclosed in braces.  Let us try the following
simple melodies:

mudela(fragment,verbatim)(
\type "Staff" <
  \type "Voice" = "one" { r4 as'4 () as'4 g'4 }
  \type "Voice" = "two" { g'2 f'4 e'4 }
>)

As you can see the result is not quite perfect.  The notes on the last
two beats look like plain chords and not like separate voices.  What
really happened was that the stems of the upper and lower voices were
printed on top of each other.

To remedy this, engravers traditionally make the stems of the lower
voice point down, and the stems of the upper up, as shown in
bind(Figure)ref(tutorial:multi-voice-fig).

Surely the direction of a single stem is a property of the stem as a
graphical object.  But the fact that all of the stems in a voice point
in the same direction is not directly graphical.  Since this is a
property shared by all the stems in the voice, this property is a
property of the context code(Voice).  The context code(Voice) has an
attribute whose value is the direction to use for stems.  You can
change it to `up' by issuing the following phrase:
verb(
  \property "Voice"."ydirection" = "1"
)

This command should be read as ``change the property called
code(ydirection) within the current code(Voice) context to the value
code(-1).''  For the property code(ydirection) the value code(1) means
`up', and code(-1) means `down'. So, the
proper way to code the polyphonic example is given in
bind(Figure)ref(tutorial:multi-voice-fig).

latexcommand(\begin{figure}[h])
mudela(fragment,verbatim,center)(
  \type "Staff" <
    \type "Voice" =  "one"  {
      \property Voice.ydirection = "1"
      r4 as'4 () as'4 g'4 }
    \type "Voice" =  "two"  {
      \property Voice.ydirection = "-1"
      g'2 f'4 e'4 }
  >
)
    latexcommand(\caption{multiple voices})
    label(tutorial:multi-voice-fig)
latexcommand(\end{figure})

As you can see, this property also controls the directions of slurs,
which explains the name code(ydirection).COMMENT(hmm)


Other properties can also be set, and they can be within different
contexts.  In general, you can set a property by specifying
code(\property) var(contexttype)code(.)var(propertyname) code(=)
var(value).  Both var(contexttype), var(propertyname) and var(value)
should be strings.

The effect of a property is pretty much hardwired into the
implementation (and thus subject to change), so we will not deal with
all the possible properties in detail. Among other characteristics that
can be set are the layout of slurs and beams.  The initialisation file
file(property.ly) explains most properties.

sect(Lyrics)
label(tutorial:lyrics)

Since a lyrics can have durations just like notes, we consider them to
be music too.  Entering lyrics in mudela has two aspects. First, you
have to enter the text, i.e., the syllables along with their
durations.  After this, you have to specify how to convert these to
graphics.

Lyrics consist of syllables, which are strings together with
durations.  Previously we only entered note names, so for entering
lyrics we have to instruct LilyPond that what we enter are not note
names but strings.  This instruction is the keyword
code(\lyrics).  After entering this keyword you can enter a musical
construct---sequential music, simultaneous music, code(\type)
entries, etc.--- but with syllables instead of pitches.  For example:
COMMENT(

)verb(\lyrics { 'got8 me on my knees4, Le-8 lie! })COMMENT(

) Next comes the conversion to notation.  LilyPond can't (yet) figure
out that lyrics need different treatment than notes.  As a result, the
default conversion will try to put the text you entered as note heads
onto a staff, and this will fail.  This default must be overridden
with a code(\type) keyword.  Printing syllables of text in a line is
done by a context called code(Lyrics).  You can select this context
with the code(\type) keyword.  Here is a simple example:
COMMENT(

)mudela(fragment,verbatim)(
\type Lyrics \lyrics { 'got8 me on my knees,4 Le-8 lie! })COMMENT(

)The result is technically correct, but it needs a melody to make it
performable: COMMENT(

)mudela(fragment,verbatim)(
  <
    \type Staff  { c''8. c''16 bes'8. a'16 g'4 f'8 g'4. }
    \type Lyrics \lyrics { 'got8. me16 on8. my16 knees,4 Le-8 lie!4. }
  >
) COMMENT(

) The strings that makes up each syllable in the lyrics block are
passed along to TeX() verbatim, so if you are proficient with TeX()
you can do various nifty things.  Just keep in mind that a syllable
either starts with a letter (a character in the range `code(a)' to
`code(z)' or `code(A)' to `code(Z)'), or it is a string enclosed
quotes. It ends with either a number for the duration, or a space.
These tricks are demonstrated in the following example:
COMMENT( urg
\type Lyrics \lyrics { 'got8 m\textbf{e}8 on8. m$\cal_Y$16 knees,4 Le-8 lie!4.}
\type Lyrics \lyrics { 'got8 m{\bf e}4 on8. m$\cal_Y$16 knees,4 Le-8 lie!4.}
)COMMENT(

)mudela(fragment,verbatim)(<
  \type Staff  { c''8. c''16 bes'8. a'16 g'4 f'8 g'4. }
  \type Lyrics \lyrics { 'got8 me8 on8. m$\cal_Y$16 "3s,"4 Le-8 lie!4.}
>
)COMMENT(


)
COMMENT(Groen is de kleur van geluk.)
COMMENT(Dat geldt zeker voor Bj"ork)

sect(Toplevel Mudela)

Back in bind(Section)ref(sec:firsttune) we said we would defer
discussion of toplevel constructions (e.g., code(\score)) to a later
moment in time: and now we will look at these constructions.  In
general, Mudela looks like set of nested `blocks'.  The general syntax
for a block is code(\keyword { ... }).

We will now discuss identifiers.  Generally you can define an
identifier by entering code(identifierName = ... ) where there can be
a variety of things on the ellipsis.
COMMENT(
Here is a (partial) list of what you can abbreviate with identifiers
at top-level.
itemize(
it()The code(\score) block
it()The code(\paper) block
it()The code(\midi) block (to be explained in
  bind(Section)ref(tutorial:sound))
it()Music (sequential music, simultaneous music etc.)
it()Durations
it()Strings
it()Translators (to be explained in bind(Section)ref(tutorial:engravers))
it()Integers
it()Reals  
)
)

When you refer
to the abbreviated entity, you must precede code(identifierName)
with a backslash, i.e., code(\identifierName).  For example:
mudela(verbatim)(
  czerny = \notes { [c16 g e g] }
  \score {
    \notes \type GrandStaff <
      { c''2 g''2 }
      { \clef bass; \czerny \czerny \czerny \czerny}
    >
    \paper {
      linewidth = -1.0;
      stem_length = 6.0*\interline;
    }
  }
)


Another interesting feature of this example are the assignments within
the paper block.  Some blocks, such as code(\paper), have a scope of
their own.  In the case of the code(\paper) block, these variables
influence the characteristics of the output.  As is shown, you can
tune quantities like the stemlength, and enter simple
nop(expressions.)footnote(The purpose of the negative linewidth is to
prevent the music from being justified.)  The identifiers that are
meaningful are for the paper block is strongly implementation
dependent, so they will not be listed here.  Moreover, since most of
the values are predefined to sensible defaults, there usually is no
need to tune these values.

Recall the properties of a context, that could be set with
code(\property).  It is a very general mechanism to tune the output of
the music, that is neatly separated from the real music.
Unfortunately, it is not convenient to type or read, and the precise
effect of a setting property isn't always apparent from its
definition.  To remedy this, we can use an identifier to capture the
meaning of a code(\property).

mudela(verbatim)(
stemup = \property Voice.ydirection = "1"
stemdown = \property Voice.ydirection = "-1"
shift = \property Voice.hshift = "1"
\score {
  \type "Staff" \notes <
    \type "Voice" =  "one"  { \stemup r4 as'4 () as'4 g'4 }
    \type "Voice" =  "two"  { \stemup \shift g'2 f'4 e'4 }
    \type "Voice" = "three" { \stemdown [d'8 dis'] [d' cis'] [c' b] c'4 } >
  \paper{  linewidth = -1.0\pt; }
})

Several abbreviations like code(\stemup) are defined in the standard
initialisation file file(property.ly).  Setting or changing context
properties can have a similar effect as the commands that were
discussed in bind(Section)ref(sec:commands).  Don't be fooled by the
similarity in appearance between a declared property-setting entry and
a real command like code(\clef) or code(\bar).  Real commands are
hardcoded into the language and they have to be terminated by
semicolons.

You can also use identifiers to break up the heavy nesting that can
occur in the code(\score) block.  Another useful application is
parametrisation of the music: if you use identifiers in the
code(\score) block, you can make variations of the music by simply
redefining those identifiers.  One particular application of this is
part extraction: by using identifiers and redefining them, one can
print extracted parts and a full orchestral score from the same music
definition.


sect(Sound output)
label(tutorial:sound)

You get output by combining music with definition a conversion to
output.  LilyPond currently supports one other conversion besides
notation: the conversion from abstract music to sound. You can have
LilyPond play the music that you entered.  The format that is used for
this output is MIDI.  The result is not very pretty, but it is useful
for prooflistening your files: typing errors stand out when you
listen, especially if they involve accidentals.

The only information that you need to enter is the
tempo. (Unfortunately, at this time, this the only thing that can be
tuned.  The syntax for the tempo is code(\tempo )var(duration) =
var(beatsperminute);), for example: COMMENT(


)verb(
\score {
   ...music...
   \midi { \tempo 4 = 76; }
}) COMMENT(

)

sect(Contexts revisited: engravers)
label(tutorial:engravers)

As was promised, we will now take a dive into the more wizardrous parts
of LilyPond: redefining (notation) contexts.  We previously explained
that a context 
itemize(
it()has a name
it()is a conversion from music to notation,
it()can contain other contexts
it()handles specific notation constructs
)

This characterization almost automatically explains what the definition of a
context should look like:
itemize(
it() It should have a name
it()It should be part of the ``notation output definition,'' i.e., the
  code(\paper) block
it()
  It should contain a specification of what other contexts may be contained
  in the context we're defining.
it()
  It should contain a list of the notation constructs  to be
  handled.
)

LilyPond can create notation for a large number of symbols.  This code
is split up into basic building blocks. Each building block is called
an em(engraver), and an engraver generally handles only one notation
construct: the code(Clef_engraver) takes care of the clefs, the
code(Time_signature_engraver) takes care of printing time signatures.

A notation context is formed by a group of engravers.  A special class
in LilyPond---the code(Engraver_group_engraver)---allows engravers to
cooperate in a group.  A variant of this grouping object is the
code(Line_group_engraver_group), which puts the output of all the
engravers (clefs, bars, etc) into a compound object, so that these
symbols can be treated as a whole.

This explains the following definition, which is a simplified Staff context:
verb(
\translator
{
        \type "Line_group_engraver_group";
        \name Staff ;

        \consists "Bar_engraver";
        \consists "Clef_engraver";
        \consists "Key_engraver";
        \consists "Local_key_engraver";
        \consists "Time_signature_engraver";
        \consists "Staff_symbol_engraver";

        defaultClef = treble;
          
        \accepts "Voice";
}) COMMENT(

) This context, named Staff, puts its graphic objects into a compound
object (a so-called ``Line group'').  At Staff level, bars, clefs,
keys, accidentals, time signatures and the staff symbol are handled.
A staff can contain a Voice context.  You can also preset properties
of contexts: for instance, the clef that is printed upon starting a
Staff, is the treble clef.

You can also declare contexts, and reference them.  This is useful in
combination with code(\remove "..."): code(\remove) does the opposite
of code(\consists).

The real context definitions are in the standard initialisation
file file(engraver.ly).

As a practical example, we will show how to typeset polymetric music,
i.e., music where the meter can differ for each staff.  The solution
is not very complicated: normally all timing information (time
signature, rhythmic grouping) is synchronised across each staff.  This
is done by having only one administration for timing information: in
the default configuration there is only one code(Timing_engraver), in
the code(Score) context.

All staffs use the information in the code(Timing_engraver) for
generating bar lines and time signatures.  So, we can have different
timing for every staff, by moving the code(Timing_engraver) into the
 Staff context.

mudela(verbatim)(
  \score {
   \notes <
     \type Staff = one { \time 2/4; c'4 c'4 c'4 c'4 c'4 c'4 }
     \type Staff = two { \time 3/4; c'4 c'4 c'4 c'4 c'4 c'4 }
   >
   \paper { 
     linewidth = -1.;
     \translator {
       \ScoreContext
       \remove "Timing_engraver";
     }
     \translator {
       \StaffContext
       \consists "Timing_engraver";
     }
  }
}
)


sect(Urtexts and context selection)
label(tutorial:urtext)

In bind(Section)ref(tutorial:more-staffs), we have shown you how to
make multiple staffs, and explained that you have to label every staff
(or more precisely: different contexts), to make sure that new ones
are created when you need them.  In this section, the real power of
this mechanism will be unveiled.

By naming other contexts that you create, you can reference other
contexts than the current context from within the music.  For example,
from within the music that you enter for staff code(One), one could
enter a small piece of music, and send it to staff code(Two), e.g.,
COMMENT(

) mudela(fragment,verbatim)(
  <
    \type Staff = one { c''4 \type Staff = two { c4 c4 } c''4 }
    \type Staff = two { \clef bass; g,4 g,4 g,4 g,4  }    
  >
)



The mechanism of context selection can be used to fabricate an
nop(Urtext)footnote(em(Urtext) is the German word for `original text'.
The Urtext edition of a piece of music, is an edition that reflects
the original writing of the composer.  Such editions are useful for
musicologists, and performers that want to perform authentic
interpretations.  However, for mere mortals, the Urtext can be quite
hard to read.  It might not contain fingering and beaming, and
typically it is full of footnotes.  Moreover, common interpretations
may have emerged---after the composer died.  For this reason, the
music that can be had as Urtext usually is also available in enhanced
and edited editions.  ) and an edited edition from em(one source).  We
will use the first few bars of bind(J.)bind(S.)Bach's first Cello
suite to demonstrate this.  The example makes heavy use of space
rests; here they are used as a placeholder to attach articulation
marks to.  

mudela(verbatim)(
  bach =  \notes \relative c { [g16 d' b' a] [b d, b' d,] }
  
  staffStuff = \notes { \clef bass; \time 4/4; s1 \bar "|."; }
  
  slursOne = \notes { s16( s s s s16 s s )s }
  slursTwo = \notes { s16-. s s() s s16() s  s ()s }

  \score{
    { < \type Voice = celloVoice { \bach \bach }
        \type Voice = celloVoice { \slursOne \slursOne }
        \staffStuff
      >
      <
        \type Voice = celloVoice { \bach \bach }
        \type Voice = celloVoice { \slursTwo \slursTwo }
        \staffStuff
      >
    }
    \paper { linewidth = -1.;}
  }
)

The slurs that you define should be put on the music that is defined
by the code(\bach) identifier.  By labeling a code(Voice) context, and
directing both the articulation and the notes to that same code(Voice)
context, the articulation is put over the right notes.


sect(Transposing)
label(tutorial:more-grammar)


One of the things that you can do with music is
em(transposing) it.  If you want to transpose a piece of music, then
you should prefix the keyword code(\transpose) along with the pitch
(relative to the central C) for the transposition.footnote(the
code(\type Staff) is to make sure that no separate staffs are created
for the code(\scale) and code(\transpose cis' \scale) part.)


mudela(verbatim)(
scale = \notes \relative c' { [c8 d e f] }
\score {
  \notes {
    \type Staff { \scale \transpose cis'  \scale }
    }
  \paper { linewidth = -1.0; }
})


sect(Staff switching)

We have seen that contexts can be nested.  This means that they form a
tree.  It is possible to edit this tree: for example, a code(Voice)
context can be taken out of a code(Staff) context, and put into
another.  This has the effect of the voice switching staffs (something
that often happens in keyboard music).  The syntax for this operation
with these particular contexts is code(\translator Staff = newStaffName).

The effect is analogous to the first example in section
ref(tutorial:urtext), but with the code(\translator) construction it
is possible to split the real music and the commands that determine in
which staff the music is printed.  For example:

mudela(verbatim)(

% real music
aVoice = \type Voice = voiceA \notes { c''4 c4 c4 c''4 }
bVoice = \type Voice = voiceB \notes { g,4 g,4 g,4 g,4  }    

% staff switching stuff
switch = \type Voice = voiceA \notes { s4 \translator Staff = staffB s4
                   s4 \translator Staff = staffA s4 }

\score {
  <
    \type Staff = staffA < \aVoice \switch >
    \type Staff = staffB < \bVoice \clef bass; >
  >
  \paper { linewidth = -1.; }
}
)

Don't try to switch staffs when you are in the middle of a slur or
beam, though: the spanners won't switch along.

sect(Hairy durations: triplets)

OUTDATED

In the previous section we explained an operation that changes the
pitches of music, transposition.  In this section we will explain an
operation that modifies the duration of the notes that you enter.
When notes are part of a triplet, then the real of duration of the
notes are 2/3 part of what their shape indicates:
mudela(fragment)(
\times 2/3 {  c'4 c'4 c'4 }
)

To support this notion, Mudela allows you to modify the duration of a
note by multiplication or division.  A code(c'4) note that would be in  a
triplet is written as code(c'4*2/3).  If you sequence a few of these
notes, you get a triplet.footnote(We added a normal staff in the example to
show the difference.)
mudela(fragment,verbatim)(
<  \type Staff = staffA { \times 2/3 { c'8 c'8 c'8 } c'4}
   \type Staff = staffB { c''8 c''8 c''4 } >)

LilyPond knows that these notes are no normal eighth notes, but the
reader doesn't yet.  To help the reader a beam or a bracket with a `3'
should be printed.  The special beam command `code([2/3)' and the
matching close beam `code(]1/1)' will take care of that, and
they also abbreviate the code(*2/3) part.  If you want brackets in
stead of beams, you can use `code(\[2/3])' and `code(\]1/1)'.
mudela(fragment,verbatim)(
< \type Staff = staffA {
    \times 2/3 { [ c'8 c'8 c'8 }
    \times 2/3 {  c'8 c'8 c'8 }
  }
  \type Staff = staffB { [c''8 c''8 c''8 c''8] }
>)

Other tuplets  can be entered in the same way.
mudela(fragment,verbatim)(
< \type Staff = staffA {
    \time 7/8;
    \times 7/6 { [c'8 c'8 c'8 c'8 c'8 c'8] }
  }
  \type Staff = staffB {
    \time 7/8;
    [c''8 c''8 c''8 c''8 c''8 c''8 c''8] } >
)

For your convenience, code([2/3) can be further abbreviated to code([/3), and
you can abbreviate code(]1/1) on the closing beam marker to code(]/1).

mudela(fragment,verbatim)(
< \type Staff = staffA {
    \times 2/3 { c'8 c'8 c'8 } c'4
  }
  \type Staff = staffB { [c''8 c''8] c''4 } >
)


bf(Important) the construct with code([/3) and
code([/1) is a hack that sets a mode in the parser.  This means that
verb(id = \notes { c8 c8 c8 }
notATriplet =\notes { [2/3 \id ]1/1 })
does not produce a triplet.  It will hopefully
soon be replaced by a construction that mixes more elegantly with the
grammar for Music.





sect(Titling)
label(tutorial:titling)

A piece of sheet music isn't complete without proper opening and
closing titles.  LilyPond does not have any real support for setting
text: that is a job best left to TeX().  But you can pass messages to
TeX() from the input file.   You can  write TeX() macros to handle
these messages.
To do this, you add a code(\header) block
to your input file.  The format is quite simple,

verb(
\header{
    "key" =  "value";
    "key" =  "value";
    "key" =  "value";
    % etc.
})

When  the results of the music typesetting are output, the contents of
code(\header) are also up into the TeX() file.  Tools like
code(ly2dvi) can use this information to generate pretty titling for
your input file. Consult the manual page of code(ly2dvi) for more
details.


The code(\header) block should be at toplevel in mudela, and
preferably at the top of the file.  If you have an input file  with
multiple code(\score) blocks, you should add a header to every score,
describing the different sub parts of the music piece, eg.


verb(\header {
        "composer" = "Ludwig Van Bavaria";
        "title" = "Symphonie Megalomane";
    }
    \score{
       ... % some music
       \header { movement = "Mit roher Kraft wild herausfahrend!"; }
      \paper { }
    }
    \score{
       ... % some more music
       \header { movement = "Saut\'e comme un oeuf."; }
      \paper { }
    }
)

If you want you can also put the code(\header) block at the top of the
input file; it will then be put into every output file automatically.
This will make it clear what the file contains as soon as you open it.