+@node Organizing pieces with variables
+@subsection Organizing pieces with variables
+
+When all of the elements discussed earlier are combined to produce
+larger files, the music expressions get a lot bigger. In
+polyphonic music with many staves, the input files can become very
+confusing. We can reduce this confusion by using
+@emph{variables}.
+
+With variables (also known as identifiers or macros), we can break
+up complex music expressions. A variable is assigned as
+follows:
+
+@example
+namedMusic = @{ @dots{} @}
+@end example
+
+The contents of the music expression @code{namedMusic} can be used
+later by placing a backslash in front of the name
+(@code{\namedMusic}, just like a normal LilyPond command).
+
+@lilypond[verbatim,quote,ragged-right]
+violin = \new Staff { \relative c'' {
+ a4 b c b
+}}
+cello = \new Staff { \relative c {
+ \clef bass
+ e2 d
+}}
+{
+ <<
+ \violin
+ \cello
+ >>
+}
+@end lilypond
+
+@noindent
+The name of a variable must have alphabetic characters only, no
+numbers, underscores, or dashes.
+
+Variables must be defined @emph{before} the main music
+expression, but may be used as many times as required anywhere after
+they have been defined. They may even be used in a later definition
+of another variable, giving a way of shortening the input if a
+section of music is repeated many times.
+
+@lilypond[verbatim,quote,ragged-right]
+tripletA = \times 2/3 { c,8 e g }
+barA = { \tripletA \tripletA \tripletA \tripletA }
+
+\relative c'' {
+ \barA \barA
+}
+@end lilypond
+
+Variables may be used for many other types of objects in
+the input. For example,
+
+@example
+width = 4.5\cm
+name = "Wendy"
+aFivePaper = \paper @{ paperheight = 21.0 \cm @}
+@end example
+
+Depending on its contents, the variable can be used in different
+places. The following example uses the above variables:
+
+@example
+\paper @{
+ \aFivePaper
+ line-width = \width
+@}
+@{ c4^\name @}
+@end example
+
+
projects / lilypond.git / blobdiff