Add compatibility for Embedded Swift

Package.swift

@@ -16,6 +16,7 @@ let cmarkPackageName = ProcessInfo.processInfo.environment["SWIFTCI_USE_LOCAL_DE
 
 let package = Package(
     name: "swift-markdown",
+    platforms: [.macOS(.v10_15)],
     products: [
         .library(
             name: "Markdown",

Sources/Markdown/Base/Document.swift

@@ -8,7 +8,9 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
+#if canImport(Foundation)
 import Foundation
+#endif
 
 /// A markup element representing the top level of a whole document.
 ///
@@ -41,7 +43,7 @@ public extension Document {
     /// - parameter options: options for parsing Markdown text.
     /// - parameter source: an explicit source URL from which the input `string` came for marking source locations.
     ///   This need not be a file URL.
-    init(parsing string: String, source: URL? = nil, options: ParseOptions = []) {
+    init(parsing string: String, source: SourceIdentifier? = nil, options: ParseOptions = []) {
         if options.contains(.parseBlockDirectives) {
             self = BlockDirectiveParser.parse(string, source: source,
                                               options: options)
@@ -50,6 +52,7 @@ public extension Document {
         }
     }
 
+    #if canImport(Foundation)
     /// Parse a file's contents into a `Document`.
     ///
     /// - parameter file: a file URL from which to load Markdown text to parse.
@@ -63,6 +66,7 @@ public extension Document {
             self = MarkupParser.parseString(string, source: file, options: options)
         }
     }
+    #endif
 
     /// Create a document from a sequence of block markup elements.
     init(_ children: some Sequence<BlockMarkup>) {
@@ -77,7 +81,9 @@ public extension Document {
 
     // MARK: Visitation
 
+    #if !hasFeature(Embedded)
     func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitDocument(self)
     }
+    #endif
 }

Sources/Markdown/Base/Markup.swift

@@ -89,11 +89,13 @@ func makeMarkup(_ data: _MarkupData) -> Markup {
 /// > Note: All supported markup elements are already implemented in the framework.
 /// Use this protocol only as a generic constraint.
 public protocol Markup {
+    #if !hasFeature(Embedded)
     /// Accept a `MarkupVisitor` and call the specific visitation method for this element.
     ///
     /// - parameter visitor: The `MarkupVisitor` visiting the element.
     /// - returns: The result of the visit.
     func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result
+    #endif
 
     /// The data backing the markup element.
     /// > Note: This property is an implementation detail; do not use it directly.
@@ -122,7 +124,7 @@ extension Markup {
     ///
     /// - Complexity: `O(1)`
     var subtreeCount: Int {
-        return raw.markup.header.subtreeCount
+        return raw.markup.subtreeCount
     }
 
     /// Return this element without ``SoftBreak`` elements, or `nil` if this
@@ -178,7 +180,7 @@ extension Markup {
     ///
     /// - Complexity: `O(1)`
     public var childCount: Int {
-        return raw.markup.header.childCount
+        return raw.markup.childCount
     }
 
     /// `true` if this element has no children.

Sources/Markdown/Base/RawMarkup.swift

@@ -8,7 +8,9 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
+#if canImport(Foundation)
 import Foundation
+#endif
 
 /// The data specific to a kind of markup element.
 ///
@@ -93,6 +95,54 @@ public struct RawMarkupHeader {
     var parsedRange: SourceRange?
 }
 
+#if hasFeature(Embedded)
+/// Embedded Swift variant: uses a plain array for children storage instead of
+/// tail-allocated ManagedBuffer elements, avoiding the self-referential generic
+/// `ManagedBuffer<RawMarkupHeader, RawMarkup>` that causes the compiler's
+/// generic specializer to hang (https://github.com/swiftlang/swift/pull/88296).
+final class RawMarkup {
+    var header: RawMarkupHeader
+    private let _children: [RawMarkup]
+
+    fileprivate static func create(data: RawMarkupData, parsedRange: SourceRange?, children: [RawMarkup]) -> RawMarkup {
+        return RawMarkup(
+            header: RawMarkupHeader(data: data,
+                                    childCount: children.count,
+                                    subtreeCount: 1 + children.subtreeCount,
+                                    parsedRange: parsedRange),
+            children: children)
+    }
+
+    private init(header: RawMarkupHeader, children: [RawMarkup]) {
+        self.header = header
+        self._children = children
+    }
+
+    var data: RawMarkupData { header.data }
+    var childCount: Int { header.childCount }
+    var subtreeCount: Int { header.subtreeCount }
+    var parsedRange: SourceRange? { header.parsedRange }
+
+    func child(at index: Int) -> RawMarkup {
+        precondition(index < header.childCount)
+        return _children[index]
+    }
+
+    func copyChildren() -> [RawMarkup] { _children }
+
+    var children: some Sequence<RawMarkup> { _children }
+
+    enum Error: Swift.Error, CustomStringConvertible {
+        case concreteConversionError(from: RawMarkup, to: Markup.Type)
+        var description: String {
+            switch self {
+            case let .concreteConversionError(raw, to: type):
+                return "Can't wrap a \(raw.data) in a \(type)"
+            }
+        }
+    }
+}
+#else
 final class RawMarkup: ManagedBuffer<RawMarkupHeader, RawMarkup> {
     enum Error: LocalizedError {
         case concreteConversionError(from: RawMarkup, to: Markup.Type)
@@ -103,7 +153,8 @@ final class RawMarkup: ManagedBuffer<RawMarkupHeader, RawMarkup> {
             }
         }
     }
-    private static func create(data: RawMarkupData, parsedRange: SourceRange?, children: [RawMarkup]) -> RawMarkup {
+
+    fileprivate static func create(data: RawMarkupData, parsedRange: SourceRange?, children: [RawMarkup]) -> RawMarkup {
         let buffer = self.create(minimumCapacity: children.count) { _ in
             RawMarkupHeader(data: data,
                             childCount: children.count,
@@ -155,17 +206,21 @@ final class RawMarkup: ManagedBuffer<RawMarkupHeader, RawMarkup> {
     }
 
     /// The children of this element.
-    var children: AnySequence<RawMarkup> {
-        return AnySequence((0..<childCount).lazy.map { Int -> RawMarkup in
-            self.child(at: 0)
-        })
+    var children: some Sequence<RawMarkup> {
+        return (0..<childCount).lazy.map { _ in self.child(at: 0) }
     }
 
     deinit {
         return self.withUnsafeMutablePointerToElements {
             $0.deinitialize(count: header.childCount)
         }
     }
+}
+#endif
+
+// MARK: - Shared API
+
+extension RawMarkup {
 
     // MARK: Aspects
 
@@ -174,11 +229,11 @@ final class RawMarkup: ManagedBuffer<RawMarkupHeader, RawMarkup> {
         if self === other {
             return true
         }
-        guard self.header.childCount == other.header.childCount,
-            self.header.data == other.header.data else {
+        guard self.childCount == other.childCount,
+            self.data == other.data else {
                 return false
         }
-        for i in 0..<header.childCount {
+        for i in 0..<childCount {
             guard self.child(at: i).hasSameStructure(as: other.child(at: i)) else {
                 return false
             }
@@ -197,16 +252,16 @@ final class RawMarkup: ManagedBuffer<RawMarkupHeader, RawMarkup> {
 
         let parsedRange: SourceRange?
         if preserveRange {
-            parsedRange = header.parsedRange
+            parsedRange = self.parsedRange
         } else {
-            parsedRange = newChild.header.parsedRange
+            parsedRange = newChild.parsedRange
         }
 
-        return RawMarkup.create(data: header.data, parsedRange: parsedRange, children: newChildren)
+        return RawMarkup.create(data: data, parsedRange: parsedRange, children: newChildren)
     }
 
     func withChildren<Children: Collection>(_ newChildren: Children) -> RawMarkup where Children.Element == RawMarkup {
-        return .create(data: header.data, parsedRange: header.parsedRange, children: Array(newChildren))
+        return .create(data: data, parsedRange: parsedRange, children: Array(newChildren))
     }
 
     // MARK: Block Creation

Sources/Markdown/Block Nodes/Block Container Blocks/BlockDirective.swift

@@ -174,7 +174,9 @@ public extension BlockDirective {
 
     // MARK: Visitation
 
+    #if !hasFeature(Embedded)
     func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitBlockDirective(self)
     }
+    #endif
 }

Sources/Markdown/Block Nodes/Block Container Blocks/BlockQuote.swift

@@ -41,7 +41,9 @@ public extension BlockQuote {
 
     // MARK: Visitation
 
+    #if !hasFeature(Embedded)
     func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitBlockQuote(self)
     }
+    #endif
 }

Sources/Markdown/Block Nodes/Block Container Blocks/CustomBlock.swift

@@ -41,7 +41,9 @@ public extension CustomBlock {
 
     // MARK: Visitation
 
+    #if !hasFeature(Embedded)
     func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitCustomBlock(self)
     }
+    #endif
 }

Sources/Markdown/Block Nodes/Block Container Blocks/Doxygen Commands/DoxygenAbstract.swift

@@ -8,8 +8,6 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
-
 /// A parsed Doxygen `\abstract` command.
 ///
 /// The Doxygen support in Swift-Markdown parses `\abstract` commands of the form
@@ -34,9 +32,11 @@ public struct DoxygenAbstract: BlockContainer {
         self._data = data
     }
 
+    #if !hasFeature(Embedded)
     public func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitDoxygenAbstract(self)
     }
+    #endif
 }
 
 public extension DoxygenAbstract {

Sources/Markdown/Block Nodes/Block Container Blocks/Doxygen Commands/DoxygenDiscussion.swift

@@ -8,8 +8,6 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
-
 /// A parsed Doxygen `\discussion` command.
 ///
 /// The Doxygen support in Swift-Markdown parses `\discussion` commands of the form
@@ -34,9 +32,11 @@ public struct DoxygenDiscussion: BlockContainer {
         self._data = data
     }
 
+    #if !hasFeature(Embedded)
     public func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitDoxygenDiscussion(self)
     }
+    #endif
 }
 
 public extension DoxygenDiscussion {

Sources/Markdown/Block Nodes/Block Container Blocks/Doxygen Commands/DoxygenNote.swift

@@ -8,8 +8,6 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
-
 /// A parsed Doxygen `\note` command.
 ///
 /// The Doxygen support in Swift-Markdown parses `\note` commands of the form
@@ -34,9 +32,11 @@ public struct DoxygenNote: BlockContainer {
         self._data = data
     }
 
+    #if !hasFeature(Embedded)
     public func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitDoxygenNote(self)
     }
+    #endif
 }
 
 public extension DoxygenNote {

Sources/Markdown/Block Nodes/Block Container Blocks/Doxygen Commands/DoxygenParameter.swift

@@ -8,8 +8,6 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
-
 /// A parsed Doxygen `\param` command.
 ///
 /// The Doxygen support in Swift-Markdown parses `\param` commands of the form
@@ -37,9 +35,11 @@ public struct DoxygenParameter: BlockContainer {
         self._data = data
     }
 
+    #if !hasFeature(Embedded)
     public func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitDoxygenParameter(self)
     }
+    #endif
 }
 
 public extension DoxygenParameter {

Sources/Markdown/Block Nodes/Block Container Blocks/Doxygen Commands/DoxygenReturns.swift

@@ -8,8 +8,6 @@
  See https://swift.org/CONTRIBUTORS.txt for Swift project authors
 */
 
-import Foundation
-
 /// A parsed Doxygen `\returns`, `\return`, or `\result` command.
 ///
 /// The Doxygen support in Swift-Markdown parses `\returns` commands of the form
@@ -34,9 +32,11 @@ public struct DoxygenReturns: BlockContainer {
         self._data = data
     }
 
+    #if !hasFeature(Embedded)
     public func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitDoxygenReturns(self)
     }
+    #endif
 }
 
 public extension DoxygenReturns {

Sources/Markdown/Block Nodes/Block Container Blocks/ListItem.swift

@@ -64,7 +64,9 @@ public extension ListItem {
 
     // MARK: Visitation
 
+    #if !hasFeature(Embedded)
     func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitListItem(self)
     }
+    #endif
 }

Sources/Markdown/Block Nodes/Block Container Blocks/OrderedList.swift

@@ -54,7 +54,9 @@ public extension OrderedList {
 
     // MARK: Visitation
 
+    #if !hasFeature(Embedded)
     func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitOrderedList(self)
     }
+    #endif
 }

Sources/Markdown/Block Nodes/Block Container Blocks/UnorderedList.swift

@@ -35,7 +35,9 @@ public extension UnorderedList {
 
     // MARK: Visitation
 
+    #if !hasFeature(Embedded)
     func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitUnorderedList(self)
     }
+    #endif
 }

Sources/Markdown/Block Nodes/Inline Container Blocks/Paragraph.swift

@@ -41,7 +41,9 @@ public extension Paragraph {
 
     // MARK: Visitation
 
+    #if !hasFeature(Embedded)
     func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
         return visitor.visitParagraph(self)
     }
+    #endif
 }