6.1 Interpretation context

• Creating contexts
• Default contexts
• Context properties
• Context evaluation
• Defining contexts
• Engravers and performers
• Defining new contexts

Interpretation contexts are objects that only exist during program run. During the interpretation phase (when interpreting music is printed on the standard output), the music expression in a \score block is interpreted in time order, the same order in which we hear and play the music. During this phase, the interpretation context holds the state for the current point within the music, for example:

• What notes are playing at this point?
• What symbols will be printed at this point?
• What is the current key signature, time signature, point within the measure, etc.?

Contexts are grouped hierarchically: A Voice (lilypond-internals) context is contained in a Staff (lilypond-internals) context (because a staff can contain multiple voices at any point), a Staff (lilypond-internals) context is contained in Score (lilypond-internals), StaffGroup (lilypond-internals), or ChoirStaff (lilypond-internals) context.

Contexts associated with sheet music output are called notation contexts, those for sound output are called performance contexts. The default definitions of the standard notation and performance contexts can be found in ly/engraver-init.ly and ly/performer-init.ly, respectively.

This page is for LilyPond-2.0.3 (stable-branch). Report errors to <bug-lilypond@gnu.org>.