Next: Style sheets, Previous: Large projects, Up: Suggestions for writing LilyPond input files
By this point, you've seen this kind of thing:
hornNotes = \relative c'' { c4 b dis c } \score { { \hornNotes } }
You may even realize that this could be useful in minimalist music:
fragmentA = \relative c'' { a4 a8. b16 } fragmentB = \relative c'' { a8. gis16 ees4 } violin = \new Staff { \fragmentA \fragmentA \fragmentB \fragmentA } \score { { \violin } }
However, you can also use these variables (also known as variables, macros, or (user-defined) command) for tweaks:
dolce = \markup{ \italic \bold dolce } padText = { \once \override TextScript #'padding = #5.0 } fthenp=_\markup{ \dynamic f \italic \small { 2nd } \hspace #0.1 \dynamic p } violin = \relative c'' { \repeat volta 2 { c4._\dolce b8 a8 g a b | \padText c4.^"hi there!" d8 e' f g d | c,4.\fthenp b8 c4 c-. | } } \score { { \violin } \layout{ragged-right=##t} }
These variables are obviously useful for saving typing. But they're worth considering even if you only use them once – they reduce complexity. Let's look at the previous example without any variables. It's a lot harder to read, especially the last line.
violin = \relative c'' { \repeat volta 2 { c4._\markup{ \italic \bold dolce } b8 a8 g a b | \once \override TextScript #'padding = #5.0 c4.^"hi there!" d8 e' f g d | c,4.\markup{ \dynamic f \italic \small { 2nd } \hspace #0.1 \dynamic p } b8 c4 c-. | } }
So far we've seen static substitution – when LilyPond
sees \padText
, it replaces it with the stuff that
we've defined it to be (ie the stuff to the right of
padtext=
).
LilyPond can handle non-static substitution, too (you can think of these as functions).
padText = #(define-music-function (parser location padding) (number?) #{ \once \override TextScript #'padding = #$padding #}) \relative c''' { c4^"piu mosso" b a b \padText #1.8 c4^"piu mosso" d e f \padText #2.6 c4^"piu mosso" fis a g }
Using variables is also a good way to reduce work if the
LilyPond input syntax changes (see Updating old input files). If
you have a single definition (such as \dolce
) for all your
input files (see Style sheets), then if the syntax changes, you
only need to update your single \dolce
definition,
instead of making changes throughout every .ly
file.
This page is for LilyPond-2.11.58 (development-branch).
Report errors to http://post.gmane.org/post.php?group=gmane.comp.gnu.lilypond.bugs.
Your suggestions for the documentation are welcome.