patch::: 1.0.9.jcn1: patsje

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

COMMENT(-*-text-*-)

redef(var)(1)(whenlatex(latexcommand({\normalfont\scshape )ARG1+latexcommand(}))\
    whenhtml(sc(ARG1)))
def(mycode)(1)(tt(ARG1))

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

TODO

in stead <-> instead
)

htmlbodyopt(bgcolor)(white)
htmlcommand(<font color=black>)

latexlayoutcmds(
\setlength{\topmargin}{-0.25in}
\setlength{\textheight}{9in}
\setlength{\textwidth}{5.875in} 
\setlength{\oddsidemargin}{0.25in}   
\setlength{\evensidemargin}{0.25in}
\input mudela-book
)

whenlatex(notableofcontents())
whentexinfo(notableofcontents())

article(Mudela, reference manual)
      (Han-Wen Nienhuys and Jan Nieuwenhuizen)
      (nop()PIPETHROUGH(date "+%B %d, %Y")()()nop())

COMMENT(

* The [ ] look weird

* paragraphs have too much space.

)


latexcommand(\def\interexample{})
latexcommand(\def\preexample{\par})
latexcommand(\def\postexample{\par\medskip})
latexcommand(\def\file#1{{code(#1)}})
COMMENT(
latexcommand(\def\texttt#1{\tt #1})
latexcommand(\def\textbf#1{\bf #1})
)

includefile(html-disclaimer.yo-urg)

bf(This document is not up to date).  All rendered examples of course
are current, but the rest probably isn't.  Adjusting the tutorial was
considered more important than writing the reference manual.  We
apologize for the inconvenience.


This document describes the the GNU LilyPond input format, which is an
effective language for defining music.  We call this language (rather
arrogantly) The Musical Definition Language or Mudela, for
short.footnote(If anybody comes up with a better name, we'd gladly
  take this. Gourlay already uses Musical Description Language,
  G-Sharp Score Definition Language.  ISO standard 10743 defines a
  Standard Music Description Language.  We're not being original here.)

The first aim of Mudela is to define a piece of music, being complete
from both from a musical typesetting, as from a musical performing
point of view.

The Musical Definition Language (Mudela), has a logical structure,
making use of identifiers, that allows for flexible input, and
definition reuse. See the documentation file file(MANIFESTO), included
with the LilyPond sources for reasons and design considerations.

The below is included for explanatory purposes only (i.e., for a
complete and up-to-date definition, see file(lily/parser.yy) and
file(lily/lexer.ll)).

As a related note, you should take a look at the examples and the init
files, as this document does not cover every aspect of Mudela yet, and
may be out of date.footnote(Ok, I am being pessimistic here.  This
just is a disclaimer.  Docs usually are written after the program
itself.)  This document intends to give an idea of how it works. It is
not a guide on how to use it.

sect(Files)

The de-facto extension of Mudela is file(.ly). Files may be included by
entering code(\include) at the start of a line:

verb(\include "a_file.ly")


sect(Syntax)

COMMENT(I don't understand the syntax, so  I can't  write  this
section very well.  --Adrian)

A one line comment is introduced by a 
code(%) character.  
Block comments are started 
by 
code(%{)
and
ended by code(%}).
They cannot be nested.

Mudela supports three types of constants: strings, reals, and integers. 
verb("I am a string"
-1.2e3          % a real
12              % an integer)
A string which contains no spaces can be written without the quotes.  
However, in Note mode, unquoted text can be intepreted as note names
rather than as a string.  

Pairs of braces `code({)' and `code(})' or pairs of angle brackets 
`code(<)' and `code(>)' are used to identify the scope
of contexts and enable the construction of hierarchical structure.
Items in braces will be treated as serial; items in angle brackets
will be stacked into chords.  
Braces are also used to group arguments for certain commands.
        
To assign an identifier you use:
verb(string = ...)
To use an identifier, you must preceed it with a backslash: code(\).
verb(oboe = \notes { ... }
\score{ \notes { \oboe }})
The left-hand part of the assignment is really a string, so 
verb("Foo bar 4 2 " = \notes { ... })
is also a valid assignment (but you would have trouble referencing it)
If you reuse identifiers, then the previous contents will be thrown
away after the right hand is evaluated, e.g.
verb(bla = \notes { \bla })
is legal.

COMMENT(It's not clear to me what things are allowed on the RHS of 
an identifier assignment.)

The following words are keywords.  You can define an identifer whose
name is a keyword, but you will not be able to reference it.

verb(absdynamic  font           time       penalty       spandynamic
accepts     grouping       midi       property      symboltables
bar         in             mm         pt            table
cadenza     include        multi      relative      tempo       
clear       lyric          header     score         translator  
clef        key            notenames  script        type        
cm          keysignature   octave     shape         transpose   
consists    mark           output     skip          version     
contains    notes        partial    staff     
duration    musicalpitch   paper      spandynamic)

COMMENT( I don't know  the proper  way to make this kind of table in
yodl.  

Also  note: Lilypond  should  really give an error when  I write
       lyric = .....  
Instead, I get the error later, after I try to use my redefinition of
\lyric.  The cause  is much less clear. )


subsect(Hierarchical structures)

The general structure consists of declarations:
verb(IDENTIFIER = \TYPE{
        <type specific data>
})
and instantiations:

verb(\TYPE{ <type specific data> })

(Currently, code(\score) is the only type that can be instantiated
at top level.)

Most instantiations that use an IDENTIFIER are specified as follows:

verb(\TYPE{ \IDENTIFIER [...] })

Some exceptions on this rule have been made to prevent inputting
Mudela becoming tedious


COMMENT(As far as I can tell, the last bit is simply a repetition of
the information on how to use an identifier, so it should be deleted.

But I'm uncertain about the meaning of \TYPE in the above section.
Different from \type?  Does it refer to \notes, \lyric?  In general,
the use of the word "type" seems to be a source of confusion.
)


sect(Modes)

To simplify different aspects of music definition (entering the notes
and manipulating them) Mudela has a number of different input "modes".
In each mode, words are identified on the input.  If code("word") is
encountered, it is treated as a string.  If code("\word") is
encountered it is treated as a keyword or as an identifier.  The
behavior of the modes differs in two ways: different modes treat
unquoted words different, and different modes have different rules for
deciding what is a word.  

description(

dit(Normal mode)
At the start of parsing, Mudela is in normal mode.
In normal mode, a word is an alphabetic character followed by
alphanumeric characters.  If code(word) is encountered on the input it
is treated as a string. 

dit(Note mode) Note mode is introduced by the keyword
code(\notes).  In Note mode, words can only contain alphabetic
characters.  If code(word) is encountered, Lilypond first checks for a
notename of code(word).  If no notename is found, then code(word) is
treated as a string.  If you mistype a notename, the parser will most
likely complain that you should be in code(\lyric) mode to do lyrics. 

dit(Lyric mode) Lyrics mode is introduced by the keyword
  code(\lyric).  Because of the various control characters that can
  appear in lyrics, e.g., foreign language accents, the inputting a
  string containing these has been made very easy.  Every sequence of
non-digit and non-white characters starting with an alphabetic
character or the code(_) is considered a word.  When code("word") is
encountered it is treated as a lyric (without the quotes).  Likewise,
when code(word) is encountered, it is treated as a lyric.  The code(_)
character is converted to a space; it provides a mechanism for
creating words that contain spaces.  
verb(a&@&@&TSI|{[    % a word
1THtrhortho     % not a "word"
Leise DOEXPAND(Fl\)DOEXPAND("u\)ss{}teren meine Sapfe       % 4 words
_ _ _ _         % 4 words: 4 spaces
))

COMMENT(Well, " seems to present some problems.  Also `` seems to be
problematic.  So the above statement isn't quite right.  Unless these
characters are considered to be "white")

COMMENT(
These modes are of a lexical nature. Normal and Note mode largely
resemble each other, save the possibility of entering Reals, 
meaning of code(_) and the resolution of words

What's this about reals?  When can you enter them or not enter them?)


sect(Note Description)

subsect(Basic note specification)

A note specification has the form 
var(pitch)[var(octavespec)][var(duration)].
The pitch of the note is specified by the note's name.  

Lilypond has predefined note names for various languages.  The default
names are the Dutch note names.  The notes are specified by the
letters code(c) through code(b), where code(c) is an octave below
middle C and the letters span the ocatave above that C.  
In Dutch, a sharp is formed by adding
code(is).  A flat is formed by adding code(es).
Double sharps and double flats are obtained by adding code(isis) or
code(eses).  
Lily has predefined sets of notenames
for various nop(languages)footnote(These 
are Dutch, English, German, Italian and Swedish.
Simply include the language specific init file file(language.ly).).
Rests are specified with the note name code(r).  There is also a note
name code(s) which produces a nonprinting note of the specified
duration.  

The optional octave specification takes the form of a series of single
quote 
code(') characters or a series of comma code(,) characters.  Each
code(') raises the pitch by one octave; each code(,) lowers the pitch
by an octave.  

mudela(fragment,verbatim,center)(
c' d' e' f' g' a' b' c''
)

mudela(fragment,verbatim,center)(
cis' dis' eis' fis' gis' ais' bis'
)

mudela(fragment,verbatim,center)(
ces' des' es' fes' ges' as' bes'
)

mudela(fragment,verbatim,center)(
cisis' eisis' gisis' aisis' beses'
)

mudela(fragment,verbatim,center)(
ceses' eses' geses' ases' beses'
)

Whenever a C-sharp is desired,  you must specify a C-sharp.  Lilypond
will determine what accidentals to  typeset  depending on the  key and
context.   
A reminder accidental can be forced by
using an exclamation mark code(!)
on a pitch.
mudela(fragment,verbatim,center)(
cis' d' e' cis'  c'! d' e' c' 
)


Durations are entered as their reciprocal values
mudela(fragment,verbatim,center)(
a'1 a'2 a'4 a a'8 a a'16 a'32 a'64
)
mudela(fragment,verbatim,center)(
r1 r2 r4 r8 r16 r32
)

If the duration is omitted then it is set equal to the previous
duration.  If there is no previous duration, then a quarter note is
assumed.  
The duration can be followed by a dot code(.) to obtain dotted note
lengths.  
mudela(fragment,verbatim,center)(
a'4. b'4.
)

In addition, the duration can be followed by a multiplier which is
introduced with the asterisk code(*) and can be an integer or a
fraction.  The multiplier changes the duration that Lilypond uses
internally for the note, but it does not change the symbol that is
printed.  
mudela(fragment,verbatim,center)(
c'4*2 c'4*2 d'8*2/3 d'8*2/3
)

Extra long notes can be obtained using the code(\breve) and
code(longa) durations:
mudela(fragment,verbatim,center)(
c'\breve gis'\longa
)


subsect(Beams and Tuplets)

A beam is specified by surrounding the beamed notes with brackets
code([) and code(]).  
mudela(fragment,verbatim,center)(
[a'8 a'] [a'16 a' a' a']
)

In order to create triplets, you must use a length multiplier after
the brackets.  An open bracket code([) followed by a fraction
instructs Lilypond to print a number over the beam, and it also
starts multiplying all note lengths by the fraction.  The closing
bracket code(]) should be followed by the fraction code(1/1) in order
to restore normal note lengths.  To create a triplet without a beam,
place a backslace code(\) before the opening and closing brackets. 

For example, in an ordinary triplet, the notes have duration 2/3 as
long as normal. 
mudela(fragment,verbatim,center)(
[2/3 a'8 a' a' ]1/1 \[2/3 b'4 b' b'\]1/1
)

There is a shorthand that can be used when you 
want notes lengths multiplied by 2/n.  
The 2 can be omitted after the open bracket
and the first 1 can be omitted after the closing bracket.  
mudela(fragment,verbatim,center)(
[/3 b'8 b' b' ]/1  \[/3 a'4 a'8\]/1
)

COMMENT(The rest of this section needs to be rewritten.  I don't
understand what's going on at all here.  The meaning of the lone ] is
unclear.  And the : syntax is also unclear.  --Adrian)   

Here is a combination
mudela(fragment,verbatim,center)(
[/3 a'8 a'16 a'] a'8 \]
)

Abbreviations
mudela(fragment,verbatim,center)(
c'1:16 [:16 e'1 g']
)

mudela(fragment,verbatim,center)(
c'4:32 [:16 c'8 d'8]
)


subsect(Slurs and Ties)

A tie connects two adjacent note heads

mudela(fragment,verbatim,center)(
e' ~ e'
)

Whereas a slur rather connects `chords', 
and tries to avoid crossing stems

mudela(fragment,verbatim,center)(
e'( )e'
)

And of course, such a (legato) slur can span several notes
mudela(fragment,verbatim,center)(
c'( d' e' )f'
)


sect(Lyrics)

Lyrics are entered like notes, with pitches replaced
by text.  For example code(Twin-4 kle4 twin-4 kle4) enters four
syllables, each with quarter note duration.  Two words can be bound
together by an underscore If a single duration   

In order to instruct Lilypond to write lyrics underneath the
staff, you must enter the lyrics context with code(\type Lyrics).  
Lyrics should be entered in lyrics mode which is entered with code(\lyric).

Two syllables or words that compose a single
duration entry are bound together using an underscore: 
code(He_could4 not4).  Here is a full example:
mudela(verbatim)(\score{ 
  <  \notes \transpose c'' {c d e c | c d e c | e f g'2 | 
                              e'4 f g'2 \bar "|."; }
     \type Lyrics \lyric { 
              DOEXPAND(Fr\)`e-4 re Ja- que DOEXPAND(Fr\)`e- re Ja- que
              Dor- mez vous?2 Dor-4 mez vous?2  }
  >
})

COMMENT(
URG
                        Fr\`e-4 re Ja- que
                        Fr\`e- re Ja- que
)



sect(Chords and Voices)

Here's a simple chord
mudela(fragment,verbatim,center)(
<c e g>
)

here are a few
mudela(fragment,verbatim,center)(
<
        { c'()d'()c' }
        { e'()f'()e' }
        { g'()a'()g' }
>
)

and similarly voices
mudela(fragment,verbatim)(
<
        { \voiceone c'4 g' c' g' }
        { \voicetwo c2 g2 }
>
)


sect(Time)  

Lilypond aligns all musical objects according to the amount of time
they occupy.  All of these objects have a duration.  When music is
written in series using braces the duration is the sum of the 
durations of the elements.  When music is stacked using angle
brackets, the duration is the maximum of the durations of the
elements.  

Because Lilypond knows the durations of all musical elements, the time
signature enables Lilypond to draw bar lines automatically.  The time
signature is specified with the code(\time) command: code(\time 3/4).
If no time signature is given, Lilypond assumes 4/4.  The automatic
generation of bar lines can toggled with the code(\cadenza) command,
and an incomplete measure at the start of the music can be created
using the code(\partial) command: code(\partial 8*2;) creates a
starting measure lasting two eighth notes.

In order to help with error checking, you can insert bar markers in
your music by typing code(|).  Whenever Lilypond encounters a code(|)
that doesn't fall at a measure boundary, she prints a warning message.

Rhythmic grouping is  a concept closely associated with this. 
A default grouping is selected for the chosen time signature.  
The default consists of combinations of 2 and 3 beats with as many
groups of 3 as possible, and the groups of 3 coming first.  For
example, 4/4 is divided into 2+2 and 8/8 is divided into 3+3+2.  This
default grouping can be changed using the \grouping command which
takes a list of durations to specify the grouping. 



sect(A complete example)
COMMENT(%label(se:complete))

A Mudela file needs some red tape

mudela(verbatim)(
\score{
        \notes {
                c' d' e' c' |
                c' d' e' c' |
                e' f' g'2 |
        }
}
)


sect(Composition: forming bigger structures)
label(sec:grammar)

The computer savy user may be interested in a more formal
specification.  We can capture what have learned about forming
sentences in Mudela in a context-free grammar.

latexcommand(\smallskip)

table(2)(lll)(
        row(cell(em(Music))cell(: em(Note)))
        row(cell()cell(code(|) em(Rest)))
        row(cell()cell(code(|) code({) em(MusicList) code(})))
        row(cell()cell(code(|) code(<) em(MusicList) code(>)))
        row(cell()cell(code(|) em(Command)))
        row(cell()cell(code(|) code(\type) em(string) code(=) em(string)  em(Music)))
        row(cell()cell(;))
        row(cell(em(MusicList))cell(: em(empty)))
        row(cell()cell(code(|)  em(MusicList)  em(Music)))
        row(cell()cell(;))
)

latexcommand(\smallskip)

In mathematics you can form expressions by combining expressions,
which are ultimately some kind of atom or terminal symbol.  The same
goes for Mudela: there are some basic building blocks, and by
combining those you create complex music.

You can combine music in three ways:
itemize(
it()If you enclose a sequence of music-elements in braces ( code({)
    and code(}) ), then you form another kind of music called
sequential music
    with those pieces.
  The duration of sequential composition is the sum of the durations of its elements
  verb(
      { c c g g a a g2 }      % twinkle twinkle
      { { c c g g} { a a g2 } }
  )
it()You can stack music by enclosing a sequence of music elements
    with code(<) and code(>). This is called simultaneous music.  
    The duration of a simultaneous composition is the maximum of the durations 
    of its elements Example:
    verb(
        <a4 {cis8 cis8} e'4>      % a-major chord
    )
it()You can form music by transposing music:
    verb(
    \transpose  
        d       % from c to the d that's almost one octave down
                { e4 f4 }       % the horizontal music
)
it()verb(\type)
it()verb(\property)
it()verb(\translator)
it()verb(\relative)
)

Of course you can also combine these three mechanisms.
verb(
{ c <c e> <c e g> <c e g \transpose d' dis > }  % 4 increasing chords
)


sect(Properties)

By default the same key signature is valid for all octaves, but
  this can be changed with the property code(keyoctaviation).


The identifier code(\specialkey) sets the property for the Staff.  A
key with two flats in one octave and three sharps in the next can be 
declared with verb(\specialkey \keysignature bes es fis' cis' gis';)

sect(Music fragments)
label(tutorial:music-fragments)

Sometimes you only need to print a small fragment of music, perhaps 
something much like one of the examples in this document.  Back in
section ref(sec:running-lilypond) we told you that the music you
enter should be encapsulated in something like:
verb(\score<
        \notes\relative c{
                d
        }
        \paper{ }
        \midi{ }
>)
where the only interesting information is this particular example is verb(
        d
)
The rest of the above example was already nicknamed `red tape'.
You may easily get bored if you have to provide this same red tape 
for every fragmenty you nop(try)footnote(Of course, in most cases your
favourite text editor (TM)
will help you out.).

Luckily there's a trick around this, and it's called file(.fly) files.
If you use the extension file(.fly) for Mudela file file(foo),
LilyPond will embed your file(foo.fly) nop(in)footnote(Or something very 
similar.  If you want to know exactly, see file(init/init.fly)):
verb(\score<
        \notes\relative c{
                <<foo.ly>>
        }
        \paper{ }
        \midi{ })
Here's how it works.  If you run LilyPond on your file file(bar.ly), you
may notice that she starts off by reading quite a number of files before
she actually reaches your file(bar.ly).  There's no magic going on, Lily
by default reads an initialisation file (file(init/init.ly)).  In the
initialisation process a lot of things are defined that you'll need for 
normal operation, such as notenames and various other mudela shortcuts,
engraver and perforer definitions, font sizes, musical dimensions and 
paper sizes.  When you use the extension file(.fly), Lily just starts
reading another initialisation file (file(init/init.fly)), that includes the 
red tape for you too.


sect(Commands)

Commands take the form of a keyword followed by a list of arguments
separated by spaces and terminated by a semicolon: 
`code(\keyword argument argument ... ;)'

COMMENT(The above is wrong. Many  commands  have the form 
         \keyword { text }
       with no semicolon, at least much of the time, and some commands
have obligatory braces as far as I can tell, which don't contain music.)

description(

dit(mycode(\absdynamic))

dit(mycode(\accepts))

dit(mycode(\bar) var(bartype)) Prints a special bar symbol, or at
measure boundaries, replaces the regular bar symbol with a special
symbol.  The argument var(bartype) is a string which specifies the
kind of bar to print.  Options are code(":|"), code("|:"),
code(":|:"), code("||"), code("|."),
code(".|"), or code(".|.").  These produce respectively a right repeat, a left
repeat, a double repeat, a double bar, a start bar, an end bar, or a
thick double bar.  If var(bartype) is set to "empty" then nothing is
printed, but a line break is allowed at that spot.

dit(mycode(\cadenza) var(togglevalue)) Toggles the automatic generation
of bar lines.  If var(togglevalue) is 0 then bar line generation is
turne off.   If var(togglevalue) is  1  then a bar is  immediately
printed and bar generation is turned  on.

dit(mycode(\clear))

dit(mycode(\clef)  var(clefname)) Sets the current clef.   The argument
is the name of the clef.  Possibilities are code(bass), code(alto),
and code(treble).  Treble clef is the default.

dit(mycode(\cm)) Specify a width in centimeters. 

dit(mycode(\consists))

dit(mycode(\contains))

dit(mycode(\duration) { var(length) var(dotcount) }) Specify note
duration.  The parameter var(length) is the negative logarithm (base
2) of duration: 1 is a half note, 2 is a quarter note, 3 is an eighth
note, etc.  The number of dots  after  the  note is given by
var(dotcount). 

dit(mycode(\font))

dit(mycode(\grouping) var(durationlist))  Sets  the  metric structure of
the measure.  
COMMENT(elaboration is needed here.)

dit(mycode(\in)) Specify a width in inches.  

dit(mycode(\include) var(file)) Include the specified file.

dit(mycode(\lyric) { var(list) } ) Parse var(list) in lyrics mode.

dit(mycode(\key) var(pitch)) Change key signature to  that of var(pitch)-major.

dit(mycode(\keysignature) var(notelist))
Specify an arbitrary key signature.  The notes from var(notelist) will
be printed in the key signature in the order that they appear on the list.

dit(mycode(\mark))

dit(mycode(\notes) var(music)) Enter note mode and process the
specified music. 

dit(mycode(\musicalpitch) { var(octave) var(note) var(shift) }) Specify
note pitch.  The octave is specified by an integer, zero for the
octave containing middle C.  The note is a number from 0 to 7, with 0
corresponding to C and 7 corresponding to B.  The shift is zero for a
natural, negative to add flats, or positive to add sharps.

dit(mycode(\time) var(numerator)mycode(/)var(denominator)) Change the time
signature.  The default time signature  is 4/4.  

dit(mycode(\midi)) Produce musical output.  See code(\tempo) for setting
the tempo.

dit(mycode(\mm)) Specify a width in millimeters. 

dit(mycode(\multi))

dit(mycode(\header) { var(key1) = var(val1); var(key2) = var(val2); ... })
Specifies information about the music.  A header should appear at the
top of the file describing the file's contents.  If a file has
multiple code(\score) blocks, then a header should appear in
each score block describing its contents.  Tools like code(ly2dvi) can
use this information for generating titles.   Some possible key values
are: title, opus, description, composer, enteredby, and copyright.

dit(mycode(\notenames) { var(list) }) Define new note names.  
The argument var(list) is a list of  definitions of  the form
var(name) = var(pitch),  where var(pitch) is specified with the
code(\musicalpitch) command.  

dit(mycode(\octave))
dit(mycode(\nop(output)))

dit(mycode(\partial) var(duration)) Specify that the first measure of
the music lasts only for the specified duration.

dit(mycode(\paper) mycode({) [ mycode(linewidth = )var(width)mycode(;) ] mycode(})) 
Appears in a score block to indicate that the music should be printed.
The line width can be set to -1.  in order to prevent justification of
small fragments of music, or the width can be specified explicitly
using code(\cm), code(\in), code(\mm), or code(\pt) to specify the
units.

dit(mycode(\penalty))

dit(mycode(\property))

dit(mycode(\pt)) Specify a width in points. 

dit(mycode(\relative) var(pitch) var(music)) Processes the specified
var(music) in relative pitch
mode.  In this mode, the octave of a pitch note is chosen so that the
note is closest to the preceeding note.  
The argument var(pitch) is
the starting pitch for this comparision.  In the case of chords, the
first note of a chord is used as the base for the pitches in the next
chord.  

dit(mycode(\score)) Start a music definition.

dit(mycode(\script))

dit(mycode(\shape))

dit(mycode(\skip))

dit(mycode(\staff))

dit(mycode(\spandynamic))
dit(mycode(\symboltables))
dit(mycode(\table))

dit(mycode(\tempo) var(duration) = var(perminute)) Used when creating
MIDI output to specify the tempo.  For example, 
`code(\midi { \temp0 4 = 76})' requests output with 76 quarter notes
per minute.  

dit(mycode(\translator))
dit(mycode(\type))

dit(mycode(\transpose) var(pitch) var(music)) Transposes the specified
music.  Middle C is tranposed to var(pitch). 

dit(mycode(\version) var(string)) Specify the version of Lilypond that
a file was written for.  The argument is the version number,
for example code("1.0.4").

)