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Library Infrastructure for LilyPond add-ons

oll-core is the heart of openLilyLib and provides common functionality that any ”openLilyLib” package uses. However, it is also useful for inclusion in arbitrary LilyPond files.

Note: this code (and documentation) is currently in a conceptual state of pre-alpha quality.

Overview for files using oll-core directly

This is only a short outline of the functionality that is automatically provided as soon as oll-core is loaded (implicitly or explicitly).

Option handling

openLilyLib packages support configuration with the \setOption command. Users can make use of that mechanism as well to make their files easily configurable.


A number of logging commands can be used in conjunction with a settable log level.

Miscellaneous internals

LilyPond version predicates

oll-core provides predicates to match against the currently running LilyPond version. This makes it possible to write code that supports multiple LilyPond versions, which can be particularly appropriate for libraries.

Simplified and extended access to association lists

oll-core provides functions to get and set values from association lists, with specific concern of nested lists or “trees”.

OS independent path handling

The os-path module (naming inspired by Python) provides a number of commands that simplify dealing with paths and file names.


Library Infrastructure for LilyPond add-ons






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