Mihaela Mihaljevic
6b7853f2d5
Rebuild the XPath engine on the parent-aware tree. Add an XPath node abstraction (tree, attribute, namespace) with document order, and navigate all thirteen axes: child, descendant, parent, ancestor, following-sibling, preceding-sibling, following, preceding, attribute, namespace, self, descendant-or-self, ancestor-or-self. Support the ./../@/// abbreviations and processing-instruction() node tests. Reverse axes number nearest-first for positional predicates; results return de-duplicated in document order. The attribute axis excludes xmlns declarations; the namespace axis surfaces in-scope namespace nodes. Closes #40
39 lines
1.7 KiB
Swift
39 lines
1.7 KiB
Swift
public extension PureXML.XPath {
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/// A compiled XPath location-path query: all thirteen axes (`child`,
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/// `descendant`, `parent`, `ancestor`, `following-sibling`,
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/// `preceding-sibling`, `following`, `preceding`, `attribute`, `namespace`,
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/// `self`, `descendant-or-self`, `ancestor-or-self`) with their abbreviations
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/// (`.`, `..`, `@`, `//`), the node tests (name, `*`, `text()`, `node()`,
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/// `comment()`, `processing-instruction()`), and the predicate subset `[n]`,
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/// `[@a]`, `[@a='v']`, `[child]`, `[child='v']`.
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///
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/// The expression language (operators, the full function library, variables)
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/// arrives in later steps. Reimplemented from the XPath 1.0 specification.
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struct Query: Sendable {
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let absolute: Bool
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let steps: [Step]
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/// Compiles an XPath location path, throwing ``QueryError`` on a path
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/// outside the supported grammar.
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public init(_ path: String) throws {
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(absolute, steps) = try Compiler.compile(path)
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}
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/// Evaluates the query over a node, returning the selected node-set in
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/// document order. The node is the starting context.
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public func evaluate(over node: PureXML.Model.Node) -> [Selection] {
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Evaluator.evaluate(steps: steps, over: node)
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}
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/// Evaluates the query and returns the selected elements only.
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public func elements(over node: PureXML.Model.Node) -> [PureXML.Model.Element] {
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evaluate(over: node).compactMap(\.element)
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}
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/// Evaluates the query and returns the string-value of each selection.
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public func strings(over node: PureXML.Model.Node) -> [String] {
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evaluate(over: node).map(\.stringValue)
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}
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}
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}
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