Add support for Doxygen discussion/note tags (#159)

* Fix DoxygenReturns doc comments

* Add support for parsing Doxygen \discussion and \note block-level commands

* Add some tests

* Update CMakeLists.txt

Author: j-f1

Sources/Markdown/Base/Markup.swift

@@ -71,6 +71,10 @@ func makeMarkup(_ data: _MarkupData) -> Markup {
         return SymbolLink(data)
     case .inlineAttributes:
         return InlineAttributes(data)
+    case .doxygenDiscussion:
+        return DoxygenDiscussion(data)
+    case .doxygenNote:
+        return DoxygenNote(data)
     case .doxygenParam:
         return DoxygenParameter(data)
     case .doxygenReturns:

Sources/Markdown/Base/RawMarkup.swift

@@ -52,6 +52,8 @@ enum RawMarkupData: Equatable {
     case tableRow
     case tableCell(colspan: UInt, rowspan: UInt)
 
+    case doxygenDiscussion
+    case doxygenNote
     case doxygenParam(name: String)
     case doxygenReturns
 }
@@ -334,6 +336,14 @@ final class RawMarkup: ManagedBuffer<RawMarkupHeader, RawMarkup> {
         return .create(data: .tableCell(colspan: colspan, rowspan: rowspan), parsedRange: parsedRange, children: children)
     }
 
+    static func doxygenDiscussion(parsedRange: SourceRange?, _ children: [RawMarkup]) -> RawMarkup {
+        return .create(data: .doxygenDiscussion, parsedRange: parsedRange, children: children)
+    }
+
+    static func doxygenNote(parsedRange: SourceRange?, _ children: [RawMarkup]) -> RawMarkup {
+        return .create(data: .doxygenNote, parsedRange: parsedRange, children: children)
+    }
+
     static func doxygenParam(name: String, parsedRange: SourceRange?, _ children: [RawMarkup]) -> RawMarkup {
         return .create(data: .doxygenParam(name: name), parsedRange: parsedRange, children: children)
     }

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

@@ -0,0 +1,56 @@
+/*
+ This source file is part of the Swift.org open source project
+
+ Copyright (c) 2024 Apple Inc. and the Swift project authors
+ Licensed under Apache License v2.0 with Runtime Library Exception
+
+ See https://swift.org/LICENSE.txt for license information
+ 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
+/// `\discussion description`, where `description` continues until the next blank
+/// line or parsed command.
+///
+/// ```markdown
+/// \discussion This object can give other objects in your program magical powers.
+/// ```
+public struct DoxygenDiscussion: BlockContainer {
+    public var _data: _MarkupData
+
+    init(_ raw: RawMarkup) throws {
+        guard case .doxygenDiscussion = raw.data else {
+            throw RawMarkup.Error.concreteConversionError(from: raw, to: DoxygenDiscussion.self)
+        }
+        let absoluteRaw = AbsoluteRawMarkup(markup: raw, metadata: MarkupMetadata(id: .newRoot(), indexInParent: 0))
+        self.init(_MarkupData(absoluteRaw))
+    }
+
+    init(_ data: _MarkupData) {
+        self._data = data
+    }
+
+    public func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
+        return visitor.visitDoxygenDiscussion(self)
+    }
+}
+
+public extension DoxygenDiscussion {
+    /// Create a new Doxygen discussion definition.
+    ///
+    /// - Parameter children: Block child elements.
+    init<Children: Sequence>(children: Children) where Children.Element == BlockMarkup {
+        try! self.init(.doxygenDiscussion(parsedRange: nil, children.map({ $0.raw.markup })))
+    }
+
+    /// Create a new Doxygen discussion definition.
+    ///
+    /// - Parameter children: Block child elements.
+    init(children: BlockMarkup...) {
+        self.init(children: children)
+    }
+}

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

@@ -0,0 +1,56 @@
+/*
+ This source file is part of the Swift.org open source project
+
+ Copyright (c) 2024 Apple Inc. and the Swift project authors
+ Licensed under Apache License v2.0 with Runtime Library Exception
+
+ See https://swift.org/LICENSE.txt for license information
+ 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
+/// `\note description`, where `description` continues until the next blank
+/// line or parsed command.
+///
+/// ```markdown
+/// \note This method is only meant to be called an odd number of times.
+/// ```
+public struct DoxygenNote: BlockContainer {
+    public var _data: _MarkupData
+
+    init(_ raw: RawMarkup) throws {
+        guard case .doxygenNote = raw.data else {
+            throw RawMarkup.Error.concreteConversionError(from: raw, to: DoxygenNote.self)
+        }
+        let absoluteRaw = AbsoluteRawMarkup(markup: raw, metadata: MarkupMetadata(id: .newRoot(), indexInParent: 0))
+        self.init(_MarkupData(absoluteRaw))
+    }
+
+    init(_ data: _MarkupData) {
+        self._data = data
+    }
+
+    public func accept<V: MarkupVisitor>(_ visitor: inout V) -> V.Result {
+        return visitor.visitDoxygenNote(self)
+    }
+}
+
+public extension DoxygenNote {
+    /// Create a new Doxygen note definition.
+    ///
+    /// - Parameter children: Block child elements.
+    init<Children: Sequence>(children: Children) where Children.Element == BlockMarkup {
+        try! self.init(.doxygenNote(parsedRange: nil, children.map({ $0.raw.markup })))
+    }
+
+    /// Create a new Doxygen note definition.
+    ///
+    /// - Parameter children: Block child elements.
+    init(children: BlockMarkup...) {
+        self.init(children: children)
+    }
+}

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

@@ -40,17 +40,15 @@ public struct DoxygenReturns: BlockContainer {
 }
 
 public extension DoxygenReturns {
-    /// Create a new Doxygen parameter definition.
+    /// Create a new Doxygen returns definition.
     ///
-    /// - Parameter name: The name of the parameter being described.
     /// - Parameter children: Block child elements.
     init<Children: Sequence>(children: Children) where Children.Element == BlockMarkup {
         try! self.init(.doxygenReturns(parsedRange: nil, children.map({ $0.raw.markup })))
     }
 
-    /// Create a new Doxygen parameter definition.
+    /// Create a new Doxygen returns definition.
     ///
-    /// - Parameter name: The name of the parameter being described.
     /// - Parameter children: Block child elements.
     init(children: BlockMarkup...) {
         self.init(children: children)

Sources/Markdown/CMakeLists.txt

@@ -17,6 +17,8 @@ add_library(Markdown
   Base/MarkupData.swift
   Base/PlainTextConvertibleMarkup.swift
   Base/RawMarkup.swift
+  "Block Nodes/Block Container Blocks/Doxygen Commands/DoxygenDiscussion.swift"
+  "Block Nodes/Block Container Blocks/Doxygen Commands/DoxygenNote.swift"
   "Block Nodes/Block Container Blocks/Doxygen Commands/DoxygenParameter.swift"
   "Block Nodes/Block Container Blocks/Doxygen Commands/DoxygenReturns.swift"
   "Block Nodes/Block Container Blocks/BlockDirective.swift"

Sources/Markdown/Parser/BlockDirectiveParser.swift

@@ -224,11 +224,17 @@ struct PendingBlockDirective {
 
 struct PendingDoxygenCommand {
     enum CommandKind {
+        case discussion
+        case note
         case param(name: Substring)
         case returns
 
         var debugDescription: String {
             switch self {
+            case .discussion:
+                return "'discussion'"
+            case .note:
+                return "'note'"
             case .param(name: let name):
                 return "'param' Argument: '\(name)'"
             case .returns:
@@ -745,6 +751,10 @@ private enum ParseContainer: CustomStringConvertible {
             let children = ParseContainer.lineRun(lines, isInCodeFence: false)
                 .convertToRawMarkup(ranges: &ranges, parent: self, options: options)
             switch pendingDoxygenCommand.kind {
+            case .discussion:
+                return [.doxygenDiscussion(parsedRange: range, children)]
+            case .note:
+                return [.doxygenNote(parsedRange: range, children)]
             case .param(let name):
                 return [.doxygenParam(name: String(name), parsedRange: range, children)]
             case .returns:
@@ -873,7 +883,12 @@ struct ParseContainerStack {
         }) else { return nil }
         remainder.lexWhitespace()
 
+        let kind: PendingDoxygenCommand.CommandKind
         switch name.text.lowercased() {
+        case "discussion":
+            kind = .discussion
+        case "note":
+            kind = .note
         case "param":
             guard let paramName = remainder.lex(until: { ch in
                 if ch.isWhitespace {
@@ -883,26 +898,21 @@ struct ParseContainerStack {
                 }
             }) else { return nil }
             remainder.lexWhitespace()
-            var pendingCommand = PendingDoxygenCommand(
-                atLocation: at.range!.lowerBound,
-                atSignIndentation: indent?.text.count ?? 0,
-                nameLocation: name.range!.lowerBound,
-                kind: .param(name: paramName.text),
-                endLocation: name.range!.upperBound)
-            pendingCommand.addLine(remainder)
-            return (pendingCommand, remainder)
+            kind = .param(name: paramName.text)
         case "return", "returns", "result":
-            var pendingCommand = PendingDoxygenCommand(
-                atLocation: at.range!.lowerBound,
-                atSignIndentation: indent?.text.count ?? 0,
-                nameLocation: name.range!.lowerBound,
-                kind: .returns,
-                endLocation: name.range!.upperBound)
-            pendingCommand.addLine(remainder)
-            return (pendingCommand, remainder)
+            kind = .returns
         default:
             return nil
         }
+
+        var pendingCommand = PendingDoxygenCommand(
+            atLocation: at.range!.lowerBound,
+            atSignIndentation: indent?.text.count ?? 0,
+            nameLocation: name.range!.lowerBound,
+            kind: kind,
+            endLocation: name.range!.upperBound)
+        pendingCommand.addLine(remainder)
+        return (pendingCommand, remainder)
     }
 
     /// Accept a trimmed line, opening new block directives as indicated by the source,

Sources/Markdown/Visitor/MarkupVisitor.swift

@@ -275,6 +275,22 @@ public protocol MarkupVisitor {
      */
      mutating func visitInlineAttributes(_ attributes: InlineAttributes) -> Result
 
+    /**
+     Visit a `DoxygenDiscussion` element and return the result.
+
+     - parameter doxygenDiscussion: A `DoxygenDiscussion` element.
+     - returns: The result of the visit.
+     */
+    mutating func visitDoxygenDiscussion(_ doxygenDiscussion: DoxygenDiscussion) -> Result
+
+    /**
+     Visit a `DoxygenNote` element and return the result.
+
+     - parameter doxygenNote: A `DoxygenNote` element.
+     - returns: The result of the visit.
+     */
+    mutating func visitDoxygenNote(_ doxygenNote: DoxygenNote) -> Result
+
     /**
      Visit a `DoxygenParam` element and return the result.
 
@@ -389,6 +405,12 @@ extension MarkupVisitor {
     public mutating func visitInlineAttributes(_ attributes: InlineAttributes) -> Result {
         return defaultVisit(attributes)
     }
+    public mutating func visitDoxygenDiscussion(_ doxygenDiscussion: DoxygenDiscussion) -> Result {
+        return defaultVisit(doxygenDiscussion)
+    }
+    public mutating func visitDoxygenNote(_ doxygenNote: DoxygenNote) -> Result {
+        return defaultVisit(doxygenNote)
+    }
     public mutating func visitDoxygenParameter(_ doxygenParam: DoxygenParameter) -> Result {
         return defaultVisit(doxygenParam)
     }

Tests/MarkdownTests/Parsing/DoxygenCommandParserTests.swift

@@ -14,6 +14,42 @@ import XCTest
 class DoxygenCommandParserTests: XCTestCase {
     let parseOptions: ParseOptions = [.parseMinimalDoxygen, .parseBlockDirectives]
 
+    func testParseDiscussion() {
+        func assertValidParse(source: String) {
+            let document = Document(parsing: source, options: parseOptions)
+            XCTAssert(document.child(at: 0) is DoxygenDiscussion)
+
+            let expectedDump = """
+            Document
+            └─ DoxygenDiscussion
+               └─ Paragraph
+                  └─ Text "The thing."
+            """
+            XCTAssertEqual(document.debugDescription(), expectedDump)
+        }
+
+        assertValidParse(source: "@discussion The thing.")
+        assertValidParse(source: #"\discussion The thing."#)
+    }
+
+    func testParseNote() {
+        func assertValidParse(source: String) {
+            let document = Document(parsing: source, options: parseOptions)
+            XCTAssert(document.child(at: 0) is DoxygenNote)
+
+            let expectedDump = """
+            Document
+            └─ DoxygenNote
+               └─ Paragraph
+                  └─ Text "The thing."
+            """
+            XCTAssertEqual(document.debugDescription(), expectedDump)
+        }
+
+        assertValidParse(source: "@note The thing.")
+        assertValidParse(source: #"\note The thing."#)
+    }
+
     func testParseParam() throws {
         let source = """
         @param thing The thing.