<scalar>
Defines a variable object that stores a single data element of any data type.
If a list of values is assigned to the scalar object's default field, the list elements will be collapsed into a single text element if this produces a valid result, otherwise invalid will be assigned to the scalar object.
Since a scalar's job is to store data rather than display it directly, a scalar object does not itself return its contents or display data as a markup element would, however you can create a reference to a vector instance in order to get and/or manipulate the data element stored inside.
Unlike a vector, which can be entirely empty of elements, a scalar always contains exactly one value. This will be null if the scalar is cleared.