PureXML/Sources/XSLT/XSLTMatchCache.swift
Mihaela Mihaljevic da8bb6b92a feat(xslt): key() over attribute nodes, key/id match patterns, doctyped sources
key() and document() read the string value of attribute and namespace
node arguments instead of dropping them, so the Muenchian grouping
idiom works; match patterns evaluate with the XSLT function table,
making key('k','v') and id('x') patterns match; and the XSLT entry
points parse sources, stylesheets, and document() loads with doctypes
allowed, as the conformance corpora require. Xalan baseline
292 -> 263 (idkey 39 -> 16).
2026-06-10 13:29:27 +02:00

60 lines
2.9 KiB
Swift

/// What one match pattern selected: tree-node and attribute identities.
private struct PatternMatches {
var trees: Set<ObjectIdentifier> = []
var attributes: Set<PureXML.XSLT.AttributeIdentity> = []
}
extension PureXML.XSLT {
/// An attribute node's identity: its owner's identity plus its name.
struct AttributeIdentity: Hashable {
let owner: ObjectIdentifier
let name: String
}
/// Caches, per transform, the node set each match pattern selects over the
/// source tree (tree nodes and attribute nodes), so a pattern is compiled
/// and evaluated once per document rather than once per (node, template)
/// pair during template selection.
final class MatchCache {
private var matched: [String: PatternMatches] = [:]
/// The identities of the tree nodes `pattern` selects over `root`.
func nodes(matching pattern: String, over root: PureXML.Model.TreeNode, functions: PureXML.XPath.FunctionTable = .init()) -> Set<ObjectIdentifier> {
compute(pattern, root, functions).trees
}
/// The identities of the attribute nodes `pattern` selects over `root`.
func attributes(matching pattern: String, over root: PureXML.Model.TreeNode, functions: PureXML.XPath.FunctionTable = .init()) -> Set<AttributeIdentity> {
compute(pattern, root, functions).attributes
}
/// Computed and cached on first use; a branch that fails to compile
/// selects nothing. The function table makes `key()` and `id()`
/// patterns work.
private func compute(_ pattern: String, _ root: PureXML.Model.TreeNode, _ functions: PureXML.XPath.FunctionTable) -> PatternMatches {
if let cached = matched[pattern] { return cached }
var result = PatternMatches()
for branch in pattern.split(separator: "|") {
let trimmed = branch.trimmingXMLWhitespace()
let path = trimmed.hasPrefix("/") || trimmed.hasPrefix("key(") || trimmed.hasPrefix("id(") ? trimmed : "//" + trimmed
guard let query = try? PureXML.XPath.Query(path),
let value = try? query.value(atNode: .tree(root), position: 1, size: 1, variables: [:], functions: functions),
let selected = value.nodes
else { continue }
for node in selected {
switch node {
case let .tree(tree):
result.trees.insert(ObjectIdentifier(tree))
case let .attribute(owner, attribute):
result.attributes.insert(AttributeIdentity(owner: ObjectIdentifier(owner), name: attribute.name.description))
case .namespace:
break
}
}
}
matched[pattern] = result
return result
}
}
}