Update from Ralph.

[lilypond.git] / Documentation / user / repeats.itely

@c -*- coding: utf-8; mode: texinfo; -*-
@ignore
    Translation of GIT committish: FILL-IN-HEAD-COMMITTISH

    When revising a translation, copy the HEAD committish of the
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@end ignore

@c \version "2.11.51"

@node Repeats
@section Repeats

@lilypondfile[quote]{repeats-headword.ly}

Repetition is a central concept in music, and multiple notations
exist for repetitions.  LilyPond supports the following kinds of
repeats:


@table @code
@item volta
The repeated music is not written out but enclosed between repeat bar
lines.  If the repeat is at the beginning of a piece, a repeat bar
line is only printed at the end of the repeat.  Alternative endings
(volte) are printed left to right with brackets.  This is the standard
notation for repeats with alternatives.

@item unfold
The repeated music is fully written out, as many times as
specified by @var{repeatcount}.  This is useful when
entering repetitious music. 

@item percent
These are beat or measure repeats.  They look like single slashes or
percent signs.

@item tremolo
This is used to write tremolo beams.

@end table


@menu
* Long repeats::                
* Short repeats::               
@end menu

@node Long repeats
@subsection Long repeats

This section discusses how to input long (usually multi-measure)
repeats.  The repeats can take two forms: repeats enclosed between
repeat signs; or written out repeats, used to input repetitious music.
Repeat signs can also be controlled manually.

@menu
* Normal repeats::              
* Manual repeat marks::         
* Written-out repeats::  
@end menu

@cindex volta
@cindex prima volta
@cindex seconda volta
@cindex volta, prima
@cindex volta, seconda
@funindex \repeat
@funindex \alternative
@funindex \partial

@node Normal repeats
@unnumberedsubsubsec Normal repeats

The syntax for a normal repeat is

@example
\repeat volta @var{repeatcount} @var{musicexpr}
@end example

where @var{musicexpr} is a music expression.  Alternate endings can be
produced using @code{\alternative}.  In order to delimit the alternate
endings, the group of alternatives must be enclosed in a set of
braces.  If there are more repeats than there are alternate endings,
the earliest repeats are given the first alternative.

Normal repeats without alternate endings:

@lilypond[verbatim,quote,relative=2]
\repeat volta 2 { c4 d e f }
c2 d
\repeat volta 2 { d4 e f g }
@end lilypond

Normal repeats with alternate endings:

@lilypond[verbatim,quote,relative=2]
\repeat volta 4 { c4 d e f }
\alternative {
  { d2 e }
  { f2 g }
}
c1
@end lilypond


Repeats with upbeats can be entered in two ways:

@lilypond[verbatim,quote,relative=2]
\partial 4
e |
\repeat volta 4 { c2 d | e2 f | }
\alternative {
  { g4 g g e }
  { a4 a a a | b2. }
}
@end lilypond

@noindent
or

@lilypond[verbatim,quote,relative=2]
\partial 4 
\repeat volta 4 { e4 | c2 d | e2 f | }
\alternative {
  { \partial 4*3 g4 g g }
  { a4 a a a | b2. }
}
@end lilypond


@cindex repeats with ties
@cindex alternative endings with ties
@cindex ties in repeats
@cindex ties in alternative endings
@funindex \repeatTie

Ties may be added to a second ending:

@lilypond[verbatim,quote,relative=2]
c1
\repeat volta 2 { c4 d e f ~ }
\alternative {
  { f2 d }
  { f2\repeatTie f, }
}
@end lilypond

@snippets

@lilypondfile[verbatim,lilyquote,texidoc,doctitle]
{shortening-volta-brackets.ly}

@lilypondfile[verbatim,lilyquote,texidoc,doctitle]
{adding-volta-brackets-to-additional-staves.ly}


@seealso

Music Glossary: @rglos{repeat}, @rglos{volta}.

Notation Reference: @ref{Bar lines}, @ref{Modifying context plug-ins}.

Snippets: @rlsr{Repeats}.

Internals Reference: @rinternals{VoltaBracket},
@rinternals{RepeatedMusic}, @rinternals{VoltaRepeatedMusic},
@rinternals{UnfoldedRepeatedMusic}.

@knownissues

@cindex repeat, ambiguous

A nested repeat like

@example
\repeat @dots{}
\repeat @dots{}
\alternative
@end example

@noindent
is ambiguous, since it is is not clear to which @code{\repeat} the
@code{\alternative} belongs.  This ambiguity is resolved by always
having the @code{\alternative} belong to the inner @code{\repeat}.
For clarity, it is advisable to use braces in such situations.

Timing information is not remembered at the start of an alternative,
so after a repeat timing information must be reset by hand; for
example, by setting @code{Score.measurePosition} or entering
@code{\partial}.  Similarly, slurs are also not repeated.



@node Manual repeat marks
@unnumberedsubsubsec Manual repeat marks

@funindex repeatCommands

@warning{These methods are only used for displaying unusual repeat
constructs, and may produce unexpected behavior.  In most cases,
repeats should be created using the standard @code{\\repeat} command
or by printing the relevant bar lines.  For more information, see
@ref{Bar lines}.}

The property @code{repeatCommands} can be used to control the
layout of repeats.  Its value is a Scheme list of repeat commands.

@table @code
@item start-repeat
Print a @code{|:} bar line.

@lilypond[verbatim,quote,relative=2]
c1
\set Score.repeatCommands = #'(start-repeat)
d4 e f g
c1
@end lilypond

As per standard engraving practice, repeat signs are not printed
at the beginning of a piece.

@item end-repeat
Print a @code{:|} bar line:

@lilypond[verbatim,quote,relative=2]
c1
d4 e f g
\set Score.repeatCommands = #'(end-repeat)
c1
@end lilypond

@item (volta @var{number}) ... (volta #f)
Create a new volta with the specified number.  The volta bracket must
be explicitly terminated, or it will not be printed.

@lilypond[verbatim,quote,relative=2]
f4 g a b
\set Score.repeatCommands = #'((volta "2"))
g4 a g a
\set Score.repeatCommands = #'((volta #f))
c1
@end lilypond

@end table

Multiple repeat commands may occur at the same point:

@lilypond[verbatim,quote,relative=2]
f4 g a b
\set Score.repeatCommands = #'((volta "2, 5") end-repeat)
g4 a g a
c1
\set Score.repeatCommands = #'((volta #f) (volta "95") end-repeat)
b1
@end lilypond

Text can be included with the volta bracket.  The text can be a
number or numbers or markup text, see @ref{Formatting text}.  The
simplest way to use markup text is to define the markup first,
then include the the markup in a Scheme list.

@lilypond[verbatim,quote]
voltaAdLib = \markup { 1. 2. 3... \text \italic { ad lib. } }
\relative c'' {
  c1
  \set Score.repeatCommands = #(list(list 'volta voltaAdLib) 'start-repeat)
  c4 b d e
  \set Score.repeatCommands = #'((volta #f) (volta "4.") end-repeat)
  f1
  \set Score.repeatCommands = #'((volta #f))
}
@end lilypond


@snippets

@lilypondfile[verbatim,lilyquote,texidoc,doctitle]
{printing-a-repeat-sign-at-the-beginning-of-a-piece.ly}

@seealso

Notation Reference:
@ref{Bar lines},
@ref{Formatting text}.

Snippets:
@rlsr{Repeats}.

Internals Reference:
@rinternals{VoltaBracket},
@rinternals{RepeatedMusic},
@rinternals{VoltaRepeatedMusic}.


@node Written-out repeats
@unnumberedsubsubsec Written-out repeats

@cindex written-out repeats
@cindex repetitious music
@cindex repeats, written-out

By using the @code{unfold} command, repeats can be used to simplify
the writing out of repetitious music.  The syntax is

@example
\repeat unfold @var{repeatcount} @var{musicexpr}
@end example

where @var{musicexpr} is a music expressionand @var{repeatcount}
is the number of times @var{musicexpr} is repeated.

@lilypond[verbatim,quote,relative=2]
c1
\repeat unfold 2 { c4 d e f }
c1
@end lilypond

Unfold repeats can be made with alternate endings.  If there are
more repeats than there are alternate endings, the first
alternative ending is applied to the earliest endings.

@lilypond[verbatim,quote,relative=2]
c1
\repeat unfold 2 { g4 f e d }
  \alternative {
    { cis2 g' }
    { cis,2 b }
  }
c1
@end lilypond

@seealso

Snippets: @rlsr{Repeats}.

Internals Reference: @rinternals{RepeatedMusic},
@rinternals{UnfoldedRepeatedMusic}.

@node Short repeats
@subsection Short repeats

This section discusses how to input short repeats.  Short repeats can
take two basic forms: repeats of a single note to two measures,
represented by slashes or percent signs; and tremolos.

@menu
* Percent repeats::             
* Tremolo repeats::             
@end menu

@node Percent repeats
@unnumberedsubsubsec Percent repeats

@cindex percent repeats
@cindex measure repeats

Repeated short patterns of notes are supported.  The music is printed
once, and the pattern is replaced with a special sign.  Patterns that
are shorter than one measure are replaced by slashes, and patterns of
one or two measures are replaced by percent-like signs.  The syntax is

@example
@code{\repeat percent @var{number} @var{musicexpr}}
@end example

where @var{musicexpr} is a music expression. 

@lilypond[verbatim,quote,relative=2]
\repeat percent 4 { c4 }
\repeat percent 2 { b4 a g f }
\repeat percent 2 { c2 es | f4 fis g c | }
@end lilypond

@snippets

@lilypondfile[verbatim,lilyquote,texidoc,doctitle]
{percent-repeat-counter.ly}

@lilypondfile[verbatim,lilyquote,texidoc,doctitle]
{isolated-percent-repeats.ly}

@seealso

Music Glossary: @rglos{percent repeat}, @rglos{simile}.

Snippets: @rlsr{Repeats}.

Internals Reference: @rinternals{RepeatSlash},
@rinternals{PercentRepeat}, @rinternals{DoublePercentRepeat},
@rinternals{DoublePercentRepeatCounter},
@rinternals{PercentRepeatCounter}, @rinternals{PercentRepeatedMusic}.

@knownissues

Only three kinds of percent repeats are supported: a single slash
representing a single beat (regardless of the duration of the repeated
notes); a single slash with dots representing one full measure; and
two slashes with dots crossing a bar line representing two full
measures.  Neither multiple slashes representing single beat repeats
consisting of sixteenth or shorter notes, nor two slashes with dots
representing single beat repeats consisting of notes of varying
durations, are supported.


@node Tremolo repeats
@unnumberedsubsubsec Tremolo repeats

Tremolos can take two forms: alternation between two chords or two
notes, and rapid repetition of a single
note or chord. Tremolos consisting of an alternation are indicated by
adding beams between the notes or chords being alternated, while
tremolos consisting of the rapid repetition of a single note are
indicated by adding beams or slashes to a single note.

@cindex tremolo beams

To place tremolo marks between notes, use @code{\repeat} with
tremolo style:

@lilypond[quote,verbatim,relative=2]
\repeat tremolo 8 { c16 d }
\repeat tremolo 6 { c16 d }
\repeat tremolo 2 { c16 d }
@end lilypond

The @code{\repeat tremolo} syntax expects exactly two notes within
the braces, and the number of repetitions must correspond to a
note value that can be expressed with plain or dotted notes.  Thus,
@code{\repeat tremolo 7} is valid and produces a double dotted
note, but @code{\repeat tremolo 9} is not.

The duration of the tremolo equals the duration of the
braced expression multiplied by the number of repeats:
@code{\repeat tremolo 8 @{ c16 d16 @}} gives a whole note tremolo,
notated as two whole notes joined by tremolo beams. 

There are two ways to put tremolo marks on a single note.  The
@code{\repeat tremolo} syntax is also used here, in which case
the note should not be surrounded by braces:

@lilypond[quote,verbatim,ragged-right]
\repeat tremolo 4 c'16
@end lilypond

@cindex tremolo marks
@funindex tremoloFlags

The same output can be obtained by adding
@q{@code{:}[@var{number}]} after the note.  The number indicates
the duration of the subdivision, and it must be at least 8.  A
@var{number} value of 8 gives one line across the note stem.  If
the length is omitted, the last value (stored in
@code{tremoloFlags}) is used

@lilypond[quote,verbatim,relative=2]
c2:8 c:32
c: c:
@end lilypond

@seealso

Snippets: @rlsr{Repeats}.

@knownissues

Cross-staff tremolos do not work well.