@c -*- coding: utf-8; mode: texinfo; -*-
@c This file is part of lilypond.tely
@ignore
    Translation of GIT committish: FILL-IN-HEAD-COMMITTISH

    When revising a translation, copy the HEAD committish of the
    version that you are working on.  See TRANSLATION for details.
@end ignore

@node Input syntax
@chapter Input syntax

This section deals with general lilypond input syntax issues,
rather than specific notation.

@menu
* Input files::                 
* Common syntax issues TODO name?::  
* Other stuffs TODO move?::     
@end menu


@node Input files
@section Input files

The main format of input for LilyPond are text files.  By convention,
these files end with @code{.ly}.

@menu
* File structure::              
* A single music expression::   
* Multiple scores in a book::   
* Extracting fragments of notation::  
* Including LilyPond files::    
* Text encoding::               
* Different editions from one source::  
@end menu


@node File structure
@subsection File structure

A @code{.ly} file contains any number of toplevel expressions, where a
toplevel expression is one of the following

@itemize
@item
An output definition, such as @code{\paper}, @code{\midi}, and
@code{\layout}.  Such a definition at the toplevel changes the default
settings for the block entered.

@item
A direct scheme expression, such as
@code{#(set-default-paper-size "a7" 'landscape)} or
@code{#(ly:set-option 'point-and-click #f)}.

@item
A @code{\header} block.  This sets the global header block.  This
is the block containing the definitions for book-wide settings, like
composer, title, etc.

@item
A @code{\score} block.  This score will be collected with other
toplevel scores, and combined as a single @code{\book}.

This behavior can be changed by setting the variable
@code{toplevel-score-handler} at toplevel.  The default handler is
defined in the init file @file{scm/@/lily@/.scm}.

The @code{\score} must begin with a music expression, and may
contain only one music expression.

@item
A @code{\book} block logically combines multiple movements
(i.e., multiple @code{\score} blocks) in one document.  If there are
a number of @code{\scores}, one output file will be created for
each @code{\book} block, in which all corresponding movements are
concatenated.  The only reason to explicitly specify @code{\book} blocks
in a @code{.ly} file is if you wish multiple output files from a single
input file.  One exception is within lilypond-book documents, where you
explicitly have to add a @code{\book} block if you want more than a
single @code{\score} or @code{\markup} in the same example.

This behavior can be changed by setting the variable
@code{toplevel-book-handler} at toplevel.  The default handler is
defined in the init file @file{scm/@/lily@/.scm}.

@item
A compound music expression, such as
@example
@{ c'4 d' e'2 @}
@end example

This will add the piece in a @code{\score} and format it in a
single book together with all other toplevel @code{\score}s and music
expressions.  In other words, a file containing only the above
music expression will be translated into

@example
\book @{
  \score @{
    \new Staff @{
      \new Voice @{
        @{ c'4 d' e'2 @}
      @}
    @}
  @}
	\layout @{ @}
	\header @{ @}
@}
@end example

This behavior can be changed by setting the variable
@code{toplevel-music-handler} at toplevel.  The default handler is
defined in the init file @file{scm/@/lily@/.scm}.

@item
A markup text, a verse for example
@example
\markup @{
   2.  The first line verse two.
@}
@end example

Markup texts are rendered above, between or below the scores or music
expressions, wherever they appear.

@cindex variables

@item
An variable, such as
@example
foo = @{ c4 d e d @}
@end example

This can be used later on in the file by entering @code{\foo}.  The
name of an variable should have alphabetic characters only; no
numbers, underscores or dashes.

@end itemize

The following example shows three things that may be entered at
toplevel

@example
\layout @{
  % movements are non-justified by default
  ragged-right = ##t
@}

\header @{
   title = "Do-re-mi"
@}

@{ c'4 d' e2 @}
@end example


At any point in a file, any of the following lexical instructions can
be entered:

@itemize
@item @code{\version}
@item @code{\include}
@item @code{\sourcefilename}
@item @code{\sourcefileline}

@end itemize


@node A single music expression
@subsection A single music expression

A @code{\score} must contain a single music expression.  However,
this music expression may be of any size.  Recall that music
expressions may be included inside other expressions to form
larger expressions.  All of these examples are single music
expressions; note the curly braces @{ @} or angle brackets <<
>> at the beginning and ending of the music.

@example
@{ c'4 c' c' c' @}
@end example

@lilypond[ragged-right,verbatim,quote]
{
  { c'4 c' c' c'}
  { d'4 d' d' d'}
}
@end lilypond

@lilypond[ragged-right,verbatim,quote]
<<
  \new Staff { c'4 c' c' c' }
  \new Staff { d'4 d' d' d' }
>>
@end lilypond

@example
@{
  \new GrandStaff <<
    \new StaffGroup <<
      \new Staff @{ \flute @}
      \new Staff @{ \oboe @}
    >>
    \new StaffGroup <<
      \new Staff @{ \violinI @}
      \new Staff @{ \violinII @}
    >>
  >>
@}
@end example


@node Multiple scores in a book
@subsection Multiple scores in a book

@funindex \book
@cindex movements, multiple

A document may contain multiple pieces of music and texts.  Examples
of these are an etude book, or an orchestral part with multiple
movements.  Each movement is entered with a @code{\score} block,

@example
\score @{
  @var{..music..}
@}
@end example

and texts are entered with a @code{\markup} block,

@example
\markup @{
  @var{..text..}
@}
@end example

@funindex \book

All the movements and texts which appear in the same @code{.ly} file 
will normally be typeset in the form of a single output file. 

@example
\score @{
  @var{..}
@}
\markup @{
  @var{..}
@}
\score @{
  @var{..}
@}
@end example

However, if you want multiple output files from the same @code{.ly}
file, then you can add multiple @code{\book} blocks, where each such
@code{\book} block will result in a separate output.  If you do not
specify any @code{\book} block in the file, LilyPond will implicitly
treat the full file as a single @code{\book} block, see @ref{File
structure}.  One important exception is within lilypond-book documents,
where you explicitly have to add a @code{\book} block, otherwise only
the first @code{\score} or @code{\markup} will appear in the output.

The header for each piece of music can be put inside the @code{\score}
block.  The @code{piece} name from the header will be printed before
each movement.  The title for the entire book can be put inside the
@code{\book}, but if it is not present, the @code{\header} which is at
the top of the file is inserted.

@example
\header @{
  title = "Eight miniatures"
  composer = "Igor Stravinsky"
@}
\score @{
  @dots{}
  \header @{ piece = "Romanze" @}
@}
\markup @{
   ..text of second verse..
@}
\markup @{
   ..text of third verse..
@}
\score @{
  @dots{}
  \header @{ piece = "Menuetto" @}
@}
@end example

@node Extracting fragments of notation
@subsection Extracting fragments of notation

It is possible to quote small fragments of a large score directly from
the output.  This can be compared to clipping a piece of a paper score
with scissors.

This is done by definining the measures that need to be cut out
separately.  For example, including the following definition


@verbatim
\layout {
  clip-regions
  = #(list
      (cons
       (make-rhythmic-location 5 1 2)
       (make-rhythmic-location 7 3 4)))
}       
@end verbatim

@noindent
will extract a fragment starting halfway the fifth measure, ending in
the seventh measure.  The meaning of @code{5 1 2} is: after a 1/2 note
in measure 5, and @code{7 3 4} after 3 quarter notes in measure 7.

More clip regions can be defined by adding more pairs of
rhythmic-locations to the list. 

In order to use this feature, LilyPond must be invoked with
@code{-dclip-systems}.  The clips are output as EPS files, and are
converted to PDF and PNG if these formats are switched on as well.

For more information on output formats, see @rprogram{Invoking lilypond}.

@seealso

Examples: @lsr{non-notation,clip-systems.ly}


@node Including LilyPond files
@subsection Including LilyPond files

@funindex \include
@cindex including files

A large project may be split up into separate files.  To refer to another
file, use

@example
\include "otherfile.ly"
@end example

The line @code{\include "file.ly"} is equivalent to pasting the contents
of file.ly into the current file at the place where you have the
\include.  For example, for a large project you might write separate files
for each instrument part and create a @q{full score} file which brings
together the individual instrument files.

The initialization of LilyPond is done in a number of files that are
included by default when you start the program, normally transparent to the
user.  Run lilypond --verbose to see a list of paths and files that Lily
finds.

Files placed in directory @file{PATH/TO/share/lilypond/VERSION/ly/} (where
VERSION is in the form @q{2.6.1}) are on the path and available to
@code{\include}.  Files in the
current working directory are available to \include, but a file of the same
name in LilyPond's installation takes precedence.  Files are
available to \include from directories in the search path specified as an
option when invoking @code{lilypond --include=DIR} which adds DIR to the
search path.

The @code{\include} statement can use full path information, but with the Unix
convention @code{/} rather than the DOS/Windows @code{\}.  For example,
if @file{stuff.ly} is located one directory higher than the current working
directory, use

@example
\include "../stuff.ly"
@end example


@node Text encoding
@subsection Text encoding

LilyPond uses the Pango library to format multi-lingual texts, and
does not perform any input-encoding conversions.  This means that any
text, be it title, lyric text, or musical instruction containing
non-ASCII characters, must be utf-8.  The easiest way to enter such text is
by using a Unicode-aware editor and saving the file with utf-8 encoding.  Most
popular modern editors have utf-8 support, for example, vim, Emacs,
jEdit, and GEdit do.

@c  Currently not working
@ignore
Depending on the fonts installed, the following fragment shows Hebrew
and Cyrillic lyrics,

@cindex Cyrillic
@cindex Hebrew
@cindex ASCII, non

@li lypondfile[fontload]{utf-8.ly}

The @TeX{} backend does not handle encoding specially at all.  Strings
in the input are put in the output as-is.  Extents of text items in the
@TeX{} backend, are determined by reading a file created via the
@file{texstr} backend,

@example
lilypond -dbackend=texstr input/les-nereides.ly
latex les-nereides.texstr
@end example

The last command produces @file{les-nereides.textmetrics}, which is
read when you execute

@example
lilypond -dbackend=tex input/les-nereides.ly
@end example

Both @file{les-nereides.texstr} and @file{les-nereides.tex} need
suitable LaTeX wrappers to load appropriate La@TeX{} packages for
interpreting non-ASCII strings.

@end ignore

To use a Unicode escape sequence, use

@example
#(ly:export (ly:wide-char->utf-8 #x2014))
@end example


@seealso

@lsr{text,utf-8.ly}


@node Different editions from one source
@subsection Different editions from one source

@funindex \tag
@cindex tag

The @code{\tag} command marks music expressions with a name.  These
tagged expressions can be filtered out later.  With this mechanism it
is possible to make different versions of the same music source.

In the following example, we see two versions of a piece of music, one
for the full score, and one with cue notes for the instrumental part

@example
c1
<<
  \tag #'part <<
    R1 \\
    @{
      \set fontSize = #-1
      c4_"cue" f2 g4 @}
  >>
  \tag #'score R1
>>
c1
@end example

The same can be applied to articulations, texts, etc.: they are
made by prepending
@example
-\tag #@var{your-tag}
@end example
to an articulation, for example,
@example
c1-\tag #'part ^4
@end example

This defines a note with a conditional fingering indication.

@cindex keepWithTag
@cindex removeWithTag
By applying the @code{\keepWithTag} and @code{\removeWithTag}
commands, tagged expressions can be filtered.  For example,
@example
<<
  @var{the music}
  \keepWithTag #'score @var{the music}
  \keepWithTag #'part @var{the music}
>>
@end example
would yield

@lilypondfile[ragged-right,quote]{tag-filter.ly}

The arguments of the @code{\tag} command should be a symbol
(such as @code{#'score} or @code{#'part}), followed by a
music expression.  It is possible to put multiple tags on
a piece of music with multiple @code{\tag} entries,

@example
  \tag #'original-part \tag #'transposed-part @dots{}
@end example


@seealso

Examples: @lsr{parts,tag@/-filter@/.ly}


@refbugs

Multiple rests are not merged if you create the score with both tagged
sections.


@node Common syntax issues TODO name?
@section Common syntax issues TODO name?

@menu
* Up and down::                 
* Distances and measurements MAYBE MOVE::  
@end menu

@node Up and down
@subsection Up and down

TODO: everything

By default, lilypnod does a pretty jazz'n job of picking
directions.  But in some cases, it may be desirable to force a
direction.

@verbatim
-
^ _
@end verbatim

Also cover
#UP
#DOWN
#LEFT
#RIGHT.

Maybe rename section to "directions".


@node Distances and measurements MAYBE MOVE
@subsection Distances and measurements MAYBE MOVE

DISCUSS after working on other sections.

TODO: staff spaces, #UP #DOWN #LEFT #RIGHT.  Maybe move into tweaks?





@node Other stuffs TODO move?
@section Other stuffs TODO move?


@menu
* Displaying LilyPond notation::  
* Skipping corrected music::    
@end menu

@node Displaying LilyPond notation
@subsection Displaying LilyPond notation

@funindex \displayLilyMusic
Displaying a music expression in LilyPond notation can be
done using the music function @code{\displayLilyMusic}.  For example,

@example
@{
  \displayLilyMusic \transpose c a, @{ c e g a bes @}
@}
@end example

will display

@example
@{ a, cis e fis g @}
@end example

By default, LilyPond will print these messages to the console along
with all the other messages.  To split up these messages and save
the results of @code{\display@{STUFF@}}, redirect the output to
a file.

@example
lilypond file.ly >display.txt
@end example


@node Skipping corrected music
@subsection Skipping corrected music


@funindex skipTypesetting
@funindex showLastLength

When entering or copying music, usually only the music near the end (where
you
are adding notes) is interesting to view and correct.  To speed up
this correction process, it is possible to skip typesetting of all but
the last few measures.  This is achieved by putting

@verbatim
showLastLength = R1*5
\score { ... }
@end verbatim

@noindent
in your source file.  This will render only the last 5 measures
(assuming 4/4 time signature) of every @code{\score} in the input
file.  For longer pieces, rendering only a small part is often an order
of magnitude quicker than rendering it completely

Skipping parts of a score can be controlled in a more fine-grained
fashion with the property @code{Score.skipTypesetting}.  When it is
set, no typesetting is performed at all.

This property is also used to control output to the MIDI file.  Note that
it skips all events, including tempo and instrument changes.  You have
been warned.

@lilypond[quote,fragment,ragged-right,verbatim]
\relative c'' {
  c8 d
  \set Score.skipTypesetting = ##t
  e e e e e e e e
  \set Score.skipTypesetting = ##f
  c d b bes a g c2 }
@end lilypond

In polyphonic music, @code{Score.skipTypesetting} will affect all
voices and staves, saving even more time.