### 1.1.71 SequentialMusic

Music expressions concatenated.

Syntax: `\sequential { … }` or simply `{ … }`

Properties:

> `elements-callback` (procedure):

>   `#<procedure #f (m)>`

>   Return a list of children, for use by a sequential iterator. Takes a single music parameter.

> `iterator-ctor` (procedure):

>   `ly:sequential-iterator::constructor`

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

> `length-callback` (procedure):

>   `ly:music-sequence::cumulative-length-callback`

>   How to compute the duration of this music. This property can only be defined as initializer in ‘`scm/define-music-types.scm`’.

> `name` (symbol):

>   `'SequentialMusic`

>   Name of this music object.

> `start-callback` (procedure):

>   `ly:music-sequence::first-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):

>   `'(general-music sequential-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).