Spec: 4.3.8 VALUE LIST: HS_VLIST

HS_VLIST allows referencing a list of elements in other identifiers, and allows the referenced elements to be updated without requiring an update of the referring identifier record. An HS_VLIST element is one whose is HS_VLIST and whose consists of a 4-byte unsigned integer followed by a list of references to other elements. The integer specifies the number of references in the list. The references may refer to elements under the same identifier or elements from other identifiers. Each reference is encoded as an UTF8-string followed by a 4-byte unsigned integer that identifies the referenced identifier and its index.

HS_VLIST elements may be used to define administrator groups for identifiers. Each administrator (as defined in 4.3.1) in the HS_VLIST includes is a member of the administrator group. Each element reference is defined in terms of an : pair. An administrator group may also contain other administrator groups as its members. This allows administrator groups to be defined in a hierarchical fashion. Care must be taken, however, to avoid a cyclic definition of administrators or administrator groups. Multiple levels of administrator groups should be avoided due to their lack of efficiency, but will not be signaled as an error. Client software should be prepared to detect any potential cyclic definition of administrators that refer to non-existent elements and treat them as errors.

A reference to the element is as a pair of the identifier and the index of the element within the identifier record; in the DO-IRP specification this is often written with a colon as :.