PureXML/Sources/Schema/TypeDerivation.swift
Mihaela Mihaljevic 4fad612281 feat(schema): XSD derivation control (abstract, block, final, redefine)
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
2026-06-08 14:14:23 +02:00

18 lines
730 B
Swift

public extension PureXML.Schema {
/// How a named complex type is derived from its base: the base type's local
/// name and whether the derivation is an extension or a restriction. This is
/// the backbone the `block`, `final`, and `xsi:type`-substitution checks walk
/// to decide whether a derivation is permitted.
struct TypeDerivation: Sendable, Equatable {
/// The local name of the base type this type derives from.
public var base: String
/// Whether this type extends or restricts its base.
public var method: DerivationMethod
public init(base: String, method: DerivationMethod) {
self.base = base
self.method = method
}
}
}