Body:
| (Description, FormalExpression*, Alias*) |
Attributes:
Contained in:
A MethodDef defines how a data value can be obtained from a collection of other data values. The Description element must be provided and should include a prose description. This is the normative content of the MethodDef.
If a FormalExpression is provided, it must contain a machine-readable expression that implements the Description and will return a value. Multiple FormalExpressions can be provided if each has a different Context attribute, allowing the same expression to be represented in forms appropriate to multiple systems.