### 2.2.4 Auto_beam_engraver

Generate beams based on measure characteristics and observed Stems. Uses `baseMoment`, `beatStructure`, `beamExceptions`, `measureLength`, and `measurePosition` to decide when to start and stop a beam. Overriding beaming is done through Stem_engraver properties `stemLeftBeamCount` and `stemRightBeamCount`.

Music types accepted:

beam-forbid-event

Properties (read)

> `autoBeaming` (boolean)

>   If set to true then beams are generated automatically.

> `baseMoment` (moment)

>   Smallest unit of time that will stand on its own as a subdivided section.

> `beamExceptions` (list)

>   An alist of exceptions to autobeam rules that normally end on beats.

> `beamHalfMeasure` (boolean)

>   Whether to allow a beam to begin halfway through the measure in triple time, which could look like 6/8.

> `beatStructure` (list)

>   List of `baseMoment`s that are combined to make beats.

> `subdivideBeams` (boolean)

>   If set, multiple beams will be subdivided at `baseMoment` positions by only drawing one beam over the beat.

This engraver creates the following layout object(s):

Beam.

`Auto_beam_engraver` is part of the following context(s): CueVoice, DrumVoice, GregorianTranscriptionVoice, KievanVoice, MensuralVoice, PetrucciVoice, TabVoice, VaticanaVoice and Voice.

#### Internals Reference v2.18.2 (稳定分支).