A mandatory element is
automatically selected if
its parent element is selected.
optional
ps:optional
Optional elements are
selected
independently.
alternative
ps:alternative
Alternative elements are organized in groups.
Exactly one element has to be selected from a group if the parent
element is
selected (although this can be changed using range expressions).
pure::variants
allows only one
ps:alternative
group for the same parent
element.
or
ps:or
Or elements are organized in groups. At least one
element has to be selected from a group if the parent element is
selected (although
this can be changed using range expressions). pure::variants allows
only one
ps:or
group for the same parent element.
