### 1.1.30 GraceMusic

Interpret the argument as grace notes.

Properties:

> `iterator-ctor` (procedure):

>   `ly:grace-iterator::constructor`

>   Function to construct a `music-event-iterator` object for this music.

> `length` (moment):

>   `#<Mom 0>`

>   The duration of this music.

> `name` (symbol):

>   `'GraceMusic`

>   Name of this music object.

> `start-callback` (procedure):

>   `ly:grace-music::start-callback`

>   Function to compute the negative length of starting grace notes. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `types` (list):

>   `'(grace-music music-wrapper-music general-music)`

>   The types of this music object; determines by what engraver this music expression is processed.

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