<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.
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.