Ladislav Lhotka <[email protected]> wrote:
> Martin Bjorklund <[email protected]> writes:
>
> > Ladislav Lhotka <[email protected]> wrote:
> >> Hi,
> >>
> >> I can't find any text in 6020bis that deals with the following issue:
> >>
> >> leaf foo {
> >> when "false()";
> >> mandatory true;
> >> type empty;
> >> }
> >>
> >> Now, sec. 7.6.5 (The leaf's mandatory Statement) says:
> >>
> >> o Otherwise, the leaf MUST exist if the ancestor node exists in the
> >> data tree.
> >>
> >> So, if we assume the ancestor node exists in the data tree, the leaf MUST
> >> exist.
> >>
> >> But sec. 8.1 (Constraints on Data) says:
> >>
> >> The following properties are true in all data trees:
> >>
> >> …
> >>
> >> o There MUST be no nodes tagged with "when" present if the "when"
> >> condition evaluates to "false" in the data tree.
> >>
> >> The "mandatory" and "when" statements contradict each other. How is
> >> this resolved?
> >
> > The idea is that a false when works like if-feature - if the when
> > evaluates to false then the mandatory constraint doesn't apply.
>
> I would personally prefer if "mandatory" was harder than "when"
But then it would never be possible augment mandatory nodes (see that
other thread).
> because
> it is a schema constraint that can be determined upfront (so is
> "if-feature"), whereas "when" needs in principle a complete data tree to
> perform the evaluation.
>
> But either way, there should be a text that states that false "when"
> wins over mandatory, or the other way around. I can't find any in -08,
> section 8 doesn't mention "mandatory" at all.
Ok. It needs to be added for "min-elements" as well:
OLD:
o The "min-elements" and "max-elements" constraints are enforced for
lists and leaf-lists.
NEW:
o The "mandatory" constraint is enforced for leafs, unless the node
or any of its ancestors has a "when" condition or "if-feature"
expression that evaluates to "false".
o The "min-elements" and "max-elements" constraints are enforced for
lists and leaf-lists, unless the node or any of its ancestors has
a "when" condition or "if-feature" expression that evaluates to
"false".
/martin
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