Mihaela Mihaljevic
1ae6680d94
Add PureXML.XPath: a compiled location-path query engine reimplemented from the XPath 1.0 specification; no upstream code copied. - Compiler parses a path into steps; Evaluator walks the tree returning a Selection node-set (node or attribute) in document order. - Forward axes only (child, descendant //, self ., attribute @), since the value model has no parent pointers. Node tests: name, *, text(), node(), comment(). Predicates: [n], [@a], [@a='v'], [child], [child='v']. - Public surface: XPath.Query (init compiles, evaluate/elements/strings), the Selection enum (element / stringValue), QueryError, and the one-shot PureXML.xpath(_:over:). Upward/sibling axes and the full expression language are explicitly out of scope. - 12 XPath tests; 61 total.
18 lines
789 B
Swift
18 lines
789 B
Swift
extension PureXML.XPath {
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/// A step predicate (`[...]`). A supported, practical subset: a position, an
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/// attribute existence or equality test, or a child-element existence or
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/// equality test.
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enum Predicate: Equatable {
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/// A one-based position, as in `book[1]`.
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case position(Int)
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/// `[@id]`: the context element has the named attribute.
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case hasAttribute(String)
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/// `[@id='x']`: the named attribute equals the value.
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case attributeEquals(name: String, value: String)
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/// `[title]`: the context element has a child element with the name.
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case hasChild(String)
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/// `[title='x']`: a child element with the name has the string value.
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case childEquals(name: String, value: String)
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}
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}
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