Make XSD validation namespace-aware and enforce the form defaults and
xs:all structural constraints that were previously ignored:
- targetNamespace is tracked: a schema's global elements are in its
target namespace, and an instance's root element must be in it.
- elementFormDefault / attributeFormDefault (and per-declaration form)
qualify local element and attribute declarations. The content-model
matcher already compares namespace URIs, so qualified declarations
now match only same-namespace instance nodes; attribute matching
became namespace-aware too.
- xs:all groups are checked at compile time: every member must be an
element occurring at most once, the group may occur at most once, and
nested model groups inside an all are rejected (a SchemaError).
When a schema has no target namespace the stamping is a no-op, so
unqualified schemas validate exactly as before.
Cross-namespace type references through xs:import resolve by local name
only; full multi-namespace type tables are not modeled.
Closes#78
Read and enforce the XSD 1.0 derivation controls that were previously
ignored:
- abstract elements may not appear in an instance directly, only through
a substitution member; an element of an abstract complex type must
supply an xsi:type naming a concrete derived type.
- block on a type forbids the disallowed xsi:type substitutions; block on
an element drops substitution-group members that derive by a blocked
method.
- final on a type rejects, at compile time, any type that derives from it
by a final method.
- xs:redefine requires the redefined type to derive from itself.
Track each named complex type's base and derivation method as the
backbone these checks walk. Also compose complexContent extension and
restriction content models, which were previously dropped: an extension
now inherits its base's attributes and content (base first, then the
extension, in sequence).
Complex-type restriction is not verified to be a structurally valid
subset of its base (Particle Valid (Restriction)); that limit is
documented at its sites.
Closes#76
