Mihaela Mihaljevic
b19e48a6eb
Add the RELAX NG pattern algebra (Pattern, NameClass), a parser for the XML syntax into a grammar of start plus named defines, and James Clark's derivative validation algorithm. The pattern is derived through each start-tag, attribute, text, and end-tag event with simplifying constructors; the document is valid when the residual pattern is nullable. Supports element, attribute, text, empty, notAllowed, group, choice, interleave, optional, zeroOrMore, oneOrMore, mixed, list, ref/define, data, value, and the name classes; handles interleave and recursive grammars, reusing the XSD datatype library for data and value. Closes #11 Closes #12
43 lines
1.6 KiB
Swift
43 lines
1.6 KiB
Swift
public extension PureXML.Schema {
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/// A RELAX NG name class: which element or attribute names a pattern matches.
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indirect enum NameClass: Sendable {
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case anyName
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case anyNameExcept(NameClass)
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case name(namespace: String, localName: String)
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case nsName(String)
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case choice(NameClass, NameClass)
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/// Whether `name` is in this class.
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func contains(_ name: PureXML.Model.QualifiedName) -> Bool {
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let namespace = name.namespaceURI ?? ""
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switch self {
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case .anyName: return true
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case let .anyNameExcept(except): return !except.contains(name)
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case let .name(wantedNamespace, wantedLocal): return namespace == wantedNamespace && name.localName == wantedLocal
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case let .nsName(wantedNamespace): return namespace == wantedNamespace
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case let .choice(left, right): return left.contains(name) || right.contains(name)
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}
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}
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}
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/// A RELAX NG pattern (the simplified algebra used by the derivative
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/// algorithm). `optional`, `zeroOrMore`, and `mixed` are expressed through
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/// these constructors; `after` is internal to derivation.
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indirect enum Pattern: Sendable {
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case empty
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case notAllowed
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case text
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case choice(Pattern, Pattern)
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case interleave(Pattern, Pattern)
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case group(Pattern, Pattern)
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case oneOrMore(Pattern)
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case element(NameClass, Pattern)
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case attribute(NameClass, Pattern)
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case data(BuiltinType)
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case value(String)
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case list(Pattern)
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case ref(String)
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case after(Pattern, Pattern)
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}
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}
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