Mihaela Mihaljevic
3ea4e6f37d
PureXML.XSLT.transform accepts parameters overriding xsl:param globals by name; xsl:variable globals are never overridable, with parameter names recorded across imports and includes. The conformance runner honors the xalan harness contract, reading <case>.param files (CRLF is one Character in Swift, so the runner splits on newline graphemes, which the param files exposed). Closes #141. Xalan baseline 128 -> 127.
389 lines
18 KiB
Swift
389 lines
18 KiB
Swift
typealias XSLTTree = PureXML.Model.TreeNode
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// The accumulating declarations of a stylesheet as its top-level elements are
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// compiled, plus the folding of an included or imported sub-stylesheet. File
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// scope and private.
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/// XSLTTree helpers for the XSLT parser. File-scope and private.
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enum XSLTNode {
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static let namespace = "http://www.w3.org/1999/XSL/Transform"
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static func localName(_ node: XSLTTree) -> String? {
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node.name?.localName
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}
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static func isXSL(_ node: XSLTTree) -> Bool {
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node.kind == .element && (node.name?.namespaceURI == namespace || node.name?.prefix == "xsl")
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}
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static func attribute(_ node: XSLTTree, _ name: String) -> String? {
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node.attributes.first { $0.name.localName == name }?.value
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}
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static func elementChildren(_ node: XSLTTree) -> [XSLTTree] {
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node.children.filter { $0.kind == .element }
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}
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static func children(_ node: XSLTTree, named name: String) -> [XSLTTree] {
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elementChildren(node).filter { localName($0) == name }
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}
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}
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public extension PureXML.XSLT {
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/// Errors compiling or running a stylesheet.
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enum XSLTError: Swift.Error, Equatable, Sendable, CustomStringConvertible {
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case notAStylesheet
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/// An `xsl:message terminate="yes"` ended the transformation with this text.
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case terminated(String)
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public var description: String {
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switch self {
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case .notAStylesheet: "the document is not an xsl:stylesheet"
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case let .terminated(message): "transformation terminated: \(message)"
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}
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}
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}
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}
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extension PureXML.XSLT {
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/// Parses an XSLT 1.0 stylesheet document into a ``Stylesheet``: its template
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/// rules (with computed default priorities) and global variables. The XSLT
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/// vocabulary is recognized by namespace or the `xsl` prefix; other elements
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/// are literal result elements.
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enum XSLTParser {
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/// Compiles a stylesheet element, folding in `xsl:include`/`xsl:import`.
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/// Compiles one stylesheet unit. Import precedences are assigned in
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/// post-order over the import tree (each import lower than its
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/// importer, later sibling imports higher than earlier ones), and a
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/// unit's templates carry the [low, precedence) range of its own
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/// import subtree, the set apply-imports searches. An included
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/// stylesheet's declarations join the including unit at its
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/// precedence; its imports join the including unit's import list.
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static func compile(_ top: XSLTTree, loader: (String) -> String?, counter: inout Int, base: String = "") -> Stylesheet {
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var parts = Parts()
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let low = counter
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var collector = XSLTUnitCollector(counter: counter)
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collectUnit(top, loader: loader, base: base, into: &collector, imports: &parts)
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counter = collector.counter
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let precedence = counter
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counter += 1
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for (child, _) in collector.declarations {
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_ = absorbDeclaration(child, into: &parts, precedence: precedence, low: low)
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}
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return parts.stylesheet
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}
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// Walks a unit's xsl children: imports compile immediately (in
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// document order, so later ones take higher precedence), includes
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// flatten recursively, other declarations are queued for the unit's
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// own precedence.
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private static func collectUnit(
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_ top: XSLTTree,
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loader: (String) -> String?,
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base: String,
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into collector: inout XSLTUnitCollector,
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imports parts: inout Parts,
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) {
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for child in XSLTNode.elementChildren(top) where XSLTNode.isXSL(child) {
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switch XSLTNode.localName(child) {
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case "import":
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parts.fold(load(child, loader: loader, counter: &collector.counter, base: base), isImport: true)
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case "include":
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if let (tree, resolved) = loadTree(child, loader: loader, base: base) {
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collector.retainedRoots.append(tree)
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collectUnit(tree, loader: loader, base: resolved, into: &collector, imports: &parts)
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}
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default:
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collector.declarations.append((child, base))
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}
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}
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}
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/// Absorbs a non-composition top-level declaration, returning whether it
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/// was one (so the caller can then try `include`/`import`).
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private static func absorbDeclaration(_ child: XSLTTree, into parts: inout Parts, precedence: Int, low: Int) -> Bool {
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switch XSLTNode.localName(child) {
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case "template": parts.templates.append(template(child, precedence: precedence, low: low))
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case "variable", "param": addGlobal(child, into: &parts)
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case "key": parts.keys.append(key(child))
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case "output": parts.output = parts.output.merged(with: parseOutput(child))
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case "strip-space": parts.stripSpace.formUnion(elementNames(child))
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case "preserve-space": parts.preserveSpace.formUnion(elementNames(child))
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case "attribute-set": addAttributeSet(child, into: &parts)
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case "decimal-format": parts.decimalFormats[XSLTNode.attribute(child, "name") ?? ""] = decimalFormat(child)
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case "namespace-alias": addNamespaceAlias(child, into: &parts)
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default: return false
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}
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return true
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}
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/// A top-level xsl:variable or xsl:param; param names are recorded
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/// so caller-supplied values can override their defaults.
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private static func addGlobal(_ child: XSLTTree, into parts: inout Parts) {
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parts.globals.append(variable(child))
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if XSLTNode.localName(child) == "param", let name = XSLTNode.attribute(child, "name") {
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parts.parameterNames.insert(name)
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}
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}
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/// The whitespace-separated element name tests of an `xsl:strip-space` or
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/// `xsl:preserve-space` element's `elements` attribute.
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private static func elementNames(_ node: XSLTTree) -> Set<String> {
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Set((XSLTNode.attribute(node, "elements") ?? "").split(whereSeparator: \.isWhitespace).map(String.init))
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}
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/// Loads an include/import target's stylesheet element: the href
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/// resolves against the importing stylesheet's own URI, which becomes
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/// the base for the loaded sheet's own includes and imports.
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private static func loadTree(_ node: XSLTTree, loader: (String) -> String?, base: String) -> (XSLTTree, String)? {
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guard let href = XSLTNode.attribute(node, "href") else { return nil }
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let resolved = base.isEmpty ? href : PureXML.XInclude.URIReference.resolve(href, against: base)
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guard let text = loader(resolved),
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let root = try? PureXML.parseTree(text, limits: .init(allowDoctype: true)), let top = stylesheetElement(root)
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else {
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return nil
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}
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return (top, resolved)
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}
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private static func load(_ node: XSLTTree, loader: (String) -> String?, counter: inout Int, base: String) -> Stylesheet? {
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guard let (top, resolved) = loadTree(node, loader: loader, base: base) else { return nil }
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return compile(top, loader: loader, counter: &counter, base: resolved)
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}
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private static func parseOutput(_ node: XSLTTree) -> Output {
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Output(
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method: XSLTNode.attribute(node, "method"),
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indent: XSLTNode.attribute(node, "indent").map { $0 == "yes" },
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omitXMLDeclaration: XSLTNode.attribute(node, "omit-xml-declaration").map { $0 == "yes" },
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encoding: XSLTNode.attribute(node, "encoding"),
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version: XSLTNode.attribute(node, "version"),
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standalone: XSLTNode.attribute(node, "standalone").map { $0 == "yes" },
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doctypePublic: XSLTNode.attribute(node, "doctype-public"),
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doctypeSystem: XSLTNode.attribute(node, "doctype-system"),
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cdataSectionElements: Set((XSLTNode.attribute(node, "cdata-section-elements") ?? "").split(whereSeparator: \.isWhitespace).map(String.init)),
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)
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}
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private static func key(_ node: XSLTTree) -> Key {
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Key(
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name: XSLTNode.attribute(node, "name") ?? "",
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match: XSLTNode.attribute(node, "match") ?? "",
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use: XSLTNode.attribute(node, "use") ?? ".",
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)
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}
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// MARK: Templates
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private static func template(_ node: XSLTTree, precedence: Int, low: Int) -> Template {
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let match = XSLTNode.attribute(node, "match")
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let priority = XSLTNode.attribute(node, "priority").flatMap(Double.init)
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?? match.map(defaultPriority) ?? 0
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let parameters = XSLTNode.children(node, named: "param").map(binding)
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let body = node.children
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.filter { !(XSLTNode.isXSL($0) && XSLTNode.localName($0) == "param") }
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.compactMap(instruction)
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return Template(
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match: match,
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name: XSLTNode.attribute(node, "name"),
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mode: XSLTNode.attribute(node, "mode"),
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priority: priority,
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importPrecedence: precedence,
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importRangeLow: low,
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parameters: parameters,
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body: body,
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namespaces: inScopeNamespaces(node).filter { !$0.key.isEmpty },
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)
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}
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private static func binding(_ node: XSLTTree) -> Binding {
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Binding(
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name: XSLTNode.attribute(node, "name") ?? "",
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select: XSLTNode.attribute(node, "select"),
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body: body(node),
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)
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}
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private static func withParameters(_ node: XSLTTree) -> [Binding] {
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XSLTNode.children(node, named: "with-param").map(binding)
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}
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/// The XSLT default-priority rules for a match pattern.
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static func defaultPriority(_ pattern: String) -> Double {
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if pattern.contains("/") || pattern.contains("[") { return 0.5 }
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if ["*", "@*", "node()", "text()", "comment()"].contains(pattern) { return -0.5 }
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if pattern.hasSuffix(":*") { return -0.25 }
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return 0
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}
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// MARK: Bodies and instructions
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static func body(_ node: XSLTTree) -> [Instruction] {
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node.children.compactMap(instruction)
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}
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static func instruction(_ node: XSLTTree) -> Instruction? {
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switch node.kind {
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case .text, .cdata:
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let value = node.value
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return value.allSatisfy { $0 == " " || $0 == "\t" || $0 == "\n" || $0 == "\r" } ? nil : .literalText(value)
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case .element:
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return XSLTNode.isXSL(node) ? xslInstruction(node) : literalElement(node)
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default:
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return nil
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}
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}
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private static func xslInstruction(_ node: XSLTTree) -> Instruction? {
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if let known = simpleInstruction(node) ?? structuralInstruction(node) { return known }
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// An unrecognized XSLT element instantiates its xsl:fallback children
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// (forwards-compatible processing); with none, it is dropped.
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let fallback = XSLTNode.children(node, named: "fallback").flatMap(body)
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return fallback.isEmpty ? nil : .fallback(body: fallback)
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}
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private static func simpleInstruction(_ node: XSLTTree) -> Instruction? {
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switch XSLTNode.localName(node) {
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case "value-of": .valueOf(
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select: XSLTNode.attribute(node, "select") ?? "",
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raw: XSLTNode.attribute(node, "disable-output-escaping") == "yes",
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)
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case "apply-templates": .applyTemplates(
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select: XSLTNode.attribute(node, "select"),
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mode: XSLTNode.attribute(node, "mode"),
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sorts: sorts(node),
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parameters: withParameters(node),
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)
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case "copy-of": .copyOf(select: XSLTNode.attribute(node, "select") ?? "")
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case "call-template": .callTemplate(
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name: XSLTNode.attribute(node, "name") ?? "",
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parameters: withParameters(node),
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)
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case "text": .literalText(
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XSLTNode.attribute(node, "disable-output-escaping") == "yes"
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? PureXML.XSLT.RawText.marked(node.stringValue)
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: node.stringValue,
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)
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case "variable", "param": variable(node)
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case "copy": .copy(useAttributeSets: useAttributeSets(node), body: body(node))
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case "message": .message(terminate: XSLTNode.attribute(node, "terminate") == "yes", body: body(node))
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case "apply-imports": .applyImports
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default: nil
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}
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}
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private static func variable(_ node: XSLTTree) -> Instruction {
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.variable(name: XSLTNode.attribute(node, "name") ?? "", select: XSLTNode.attribute(node, "select"), body: body(node))
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}
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static func choose(_ node: XSLTTree) -> Instruction {
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let whens = XSLTNode.children(node, named: "when").map { branch in
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Branch(test: XSLTNode.attribute(branch, "test") ?? "", body: body(branch))
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}
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let otherwise = XSLTNode.children(node, named: "otherwise").first.map(body) ?? []
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return .choose(whens: whens, otherwise: otherwise)
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}
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private static func literalElement(_ node: XSLTTree) -> Instruction {
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guard let name = node.name else { return .literalText("") }
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// xmlns declarations and the special xsl:* attributes (use-attribute-sets,
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// version, exclude-result-prefixes …) are not copied to the output.
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let attributes = node.attributes
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.filter { $0.name.prefix != "xmlns" && !($0.name.prefix == nil && $0.name.localName == "xmlns") && $0.name.prefix != "xsl" }
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.map { LiteralAttribute(name: $0.name, value: valueTemplate($0.value)) }
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return .literalElement(
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name: name,
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attributes: attributes,
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namespaces: copiedNamespaces(node),
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useAttributeSets: useAttributeSets(node),
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body: body(node),
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)
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}
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/// The whitespace-separated names of `[xsl:]use-attribute-sets` on `node`.
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static func useAttributeSets(_ node: XSLTTree) -> [String] {
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(XSLTNode.attribute(node, "use-attribute-sets") ?? "").split(whereSeparator: \.isWhitespace).map(String.init)
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}
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private static func caseOrder(_ node: XSLTTree) -> PureXML.XSLT.CaseOrder? {
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switch XSLTNode.attribute(node, "case-order") {
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case "upper-first": .upperFirst
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case "lower-first": .lowerFirst
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default: nil
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}
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}
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static func sorts(_ node: XSLTTree) -> [Sort] {
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XSLTNode.children(node, named: "sort").map { sort in
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Sort(
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select: XSLTNode.attribute(sort, "select") ?? ".",
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descending: XSLTNode.attribute(sort, "order") == "descending",
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numeric: XSLTNode.attribute(sort, "data-type") == "number",
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caseOrder: caseOrder(sort),
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)
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}
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}
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}
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}
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/// Top-level declaration helpers for ``XSLTParser``, kept in an extension so the
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/// parser enum stays within the type-body length budget.
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private extension PureXML.XSLT.XSLTParser {
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/// Records an `xsl:namespace-alias`: the namespace bound to `stylesheet-prefix`
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/// is rewritten to the one bound to `result-prefix` (with that prefix) on output.
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static func addNamespaceAlias(_ child: XSLTTree, into parts: inout Parts) {
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let stylePrefix = XSLTNode.attribute(child, "stylesheet-prefix") ?? "#default"
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let resultPrefix = XSLTNode.attribute(child, "result-prefix") ?? "#default"
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let key = resolvePrefix(stylePrefix, at: child) ?? ""
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parts.namespaceAliases[key] = PureXML.XSLT.NamespaceAlias(
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uri: resolvePrefix(resultPrefix, at: child),
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prefix: resultPrefix == "#default" ? nil : resultPrefix,
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)
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}
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/// Resolves a namespace prefix (or `#default`) to its URI from the `xmlns`
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/// declarations in scope at `node`, walking up to the stylesheet element.
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static func resolvePrefix(_ prefix: String, at node: XSLTTree) -> String? {
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var current: XSLTTree? = node
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while let element = current {
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for attribute in element.attributes {
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let isDefault = prefix == "#default" && attribute.name.prefix == nil && attribute.name.localName == "xmlns"
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let isPrefixed = attribute.name.prefix == "xmlns" && attribute.name.localName == prefix
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if isDefault || isPrefixed { return attribute.value }
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}
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current = element.parent
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}
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return nil
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}
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static func addAttributeSet(_ child: XSLTTree, into parts: inout Parts) {
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guard let name = XSLTNode.attribute(child, "name") else { return }
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// Same-name attribute sets merge (7.1.4) as ordered definitions:
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// each expands its used sets before its own attributes, and a later
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// definition's attributes override earlier same-named ones.
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let addition = PureXML.XSLT.AttributeSet(attributes: body(child), use: useAttributeSets(child))
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parts.attributeSets[name, default: []].append(addition)
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}
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/// Reads an `xsl:decimal-format`'s symbol overrides; each unset attribute
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/// keeps the XSLT standard default.
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static func decimalFormat(_ node: XSLTTree) -> PureXML.XSLT.DecimalFormat {
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var format = PureXML.XSLT.DecimalFormat()
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func char(_ name: String, _ keyPath: WritableKeyPath<PureXML.XSLT.DecimalFormat, Character>) {
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if let value = XSLTNode.attribute(node, name)?.first { format[keyPath: keyPath] = value }
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}
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char("decimal-separator", \.decimalSeparator)
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char("grouping-separator", \.groupingSeparator)
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char("percent", \.percent)
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char("per-mille", \.perMille)
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char("zero-digit", \.zeroDigit)
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char("digit", \.digit)
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char("pattern-separator", \.patternSeparator)
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char("minus-sign", \.minusSign)
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if let infinity = XSLTNode.attribute(node, "infinity") { format.infinity = infinity }
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if let notANumber = XSLTNode.attribute(node, "NaN") { format.notANumber = notANumber }
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return format
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}
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}
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