2.5.4 Organizing pieces with identifiers

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 identifiers.

With identifiers (also known as variables or macros), we can break up complex music expressions. An identifier is assigned as follows

namedMusic = { ... }

The contents of the music expression namedMusic can be used later by placing a backslash in front of the name (\namedMusic, just like a normal LilyPond command). Identifiers must be defined before the main music expression.

     
     violin = \new Staff { \relative c'' {
       a4 b c b
     }}
     cello = \new Staff { \relative c {
       \clef bass
       e2 d
     }}
     {
       <<
         \violin
         \cello
       >>
     }

The name of an identifier must have alphabetic characters only: no numbers, underscores, or dashes.

It is possible to use variables for many other types of objects in the input. For example,

width = 4.5\cm
name = "Wendy"
aFivePaper = \paper { paperheight = 21.0 \cm }

Depending on its contents, the identifier can be used in different places. The following example uses the above variables:

\paper {
  \aFivePaper
  line-width = \width
}
{ c4^\name }

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