Mihaela Mihaljevic
10d9525e3e
Whitespace-only text nodes are removed from the source tree for elements named by strip-space before transformation, with preserve-space and a more specific name test winning over *, and xml:space=preserve on a source element or ancestor overriding the stripping. The name sets fold across xsl:include/xsl:import. Refactors the stylesheet compile loop through a Parts accumulator to absorb the new top-level elements within the complexity budget.
50 lines
2.4 KiB
Swift
50 lines
2.4 KiB
Swift
extension PureXML.XSLT {
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/// Applies a stylesheet's `xsl:strip-space` / `xsl:preserve-space` to the
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/// source tree, removing whitespace-only text nodes from stripped elements
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/// before transformation. `xml:space="preserve"` on an element or an ancestor
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/// (until an `xml:space="default"` resets it) forces preservation regardless
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/// of `strip-space`, per the XSLT 1.0 whitespace-stripping rules. CDATA is
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/// significant and never stripped.
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enum Whitespace {
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static func strip(_ root: PureXML.Model.TreeNode, stylesheet: Stylesheet) {
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guard !stylesheet.stripSpace.isEmpty else { return }
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strip(root, stylesheet.stripSpace, stylesheet.preserveSpace, inScopePreserve: false)
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}
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private static func strip(
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_ node: PureXML.Model.TreeNode,
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_ stripSet: Set<String>,
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_ preserveSet: Set<String>,
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inScopePreserve: Bool,
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) {
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let preserveHere = xmlSpace(node).map { $0 == "preserve" } ?? inScopePreserve
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if node.kind == .element, !preserveHere, shouldStrip(node, stripSet, preserveSet) {
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for child in node.children where child.kind == .text && isWhitespace(child.value) {
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node.removeChild(child)
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}
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}
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for child in node.children {
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strip(child, stripSet, preserveSet, inScopePreserve: preserveHere)
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}
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}
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/// Whether an element with this name has its whitespace stripped: a name
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/// test wins over `*`, and `preserve-space` beats `strip-space` on a tie.
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private static func shouldStrip(_ node: PureXML.Model.TreeNode, _ stripSet: Set<String>, _ preserveSet: Set<String>) -> Bool {
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let names = [node.name?.localName, node.name?.description].compactMap(\.self)
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if names.contains(where: preserveSet.contains) { return false }
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if names.contains(where: stripSet.contains) { return true }
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if preserveSet.contains("*") { return false }
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return stripSet.contains("*")
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}
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private static func xmlSpace(_ node: PureXML.Model.TreeNode) -> String? {
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node.attributes.first { $0.name.localName == "space" && $0.name.prefix == "xml" }?.value
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}
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private static func isWhitespace(_ value: String) -> Bool {
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value.allSatisfy(\.isWhitespace)
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}
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}
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}
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