Group-based operators

These operators use a scope based on a group. From v5.6.0 they can work with sets or lists, retaining data type, or may use expressions evaluating as lists or sets.

The group may be:

• any designator from {children,descendants,sibling,ancestor,all}
• a find() (from v5.6.0)
• a list-based group designator (from v5.6.0)

Such operators are:

• any(group,value)
• avg(group,value)
• collect(group,attribute)
• every(group,value)
• linkFrom("[item|group]"[,linkType])
• linkTo("[item|group]"[,linkType])
• sum(group, value)
• unlinkFrom("[item|group]"[,linkType])
• unlinkTo("[item|group]"[,linkType])