Adding support for abstract headerdoc tag so the methods or properties with abstract headerdoc tag retains documentation

Author: binamaniar

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

@@ -17,7 +17,7 @@ import Foundation
 /// line or parsed command.
 ///
 /// ```markdown
-/// \discussion This object can give other objects in your program magical powers.
+/// \abstract This object can give other objects in your program magical powers.
 /// ```
 public struct DoxygenAbstract: BlockContainer {
     public var _data: _MarkupData
@@ -40,14 +40,14 @@ public struct DoxygenAbstract: BlockContainer {
 }
 
 public extension DoxygenAbstract {
-    /// Create a new Doxygen discussion definition.
+    /// Create a new Doxygen abstract definition.
     ///
     /// - Parameter children: Block child elements.
     init<Children: Sequence>(children: Children) where Children.Element == BlockMarkup {
         try! self.init(.doxygenAbstract(parsedRange: nil, children.map({ $0.raw.markup })))
     }
 
-    /// Create a new Doxygen discussion definition.
+    /// Create a new Doxygen abstract definition.
     ///
     /// - Parameter children: Block child elements.
     init(children: BlockMarkup...) {

Sources/Markdown/Markdown.docc/Markdown/DoxygenCommands.md

@@ -44,6 +44,7 @@ Doxygen commands are not parsed within code blocks or block directive content.
 
 ### Commands
 
+- ``DoxygenAbstract``
 - ``DoxygenDiscussion``
 - ``DoxygenNote``
 - ``DoxygenParameter``

Sources/Markdown/Walker/Walkers/MarkupFormatter.swift

@@ -1,7 +1,7 @@
 /*
  This source file is part of the Swift.org open source project
 
- Copyright (c) 2021-2024 Apple Inc. and the Swift project authors
+ Copyright (c) 2021-2025 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
@@ -1178,6 +1178,11 @@ public struct MarkupFormatter: MarkupWalker {
         descendInto(doxygenDiscussion)
     }
 
+    public mutating func visitDoxygenAbstract(_ doxygenAbstract: DoxygenAbstract) {
+        printDoxygenStart("abstract", for: doxygenAbstract)
+        descendInto(doxygenAbstract)
+    }
+
     public mutating func visitDoxygenNote(_ doxygenNote: DoxygenNote) {
         printDoxygenStart("note", for: doxygenNote)
         descendInto(doxygenNote)
@@ -1194,4 +1199,5 @@ public struct MarkupFormatter: MarkupWalker {
         printDoxygenStart("returns", for: doxygenReturns)
         descendInto(doxygenReturns)
     }
+
 }

Tests/MarkdownTests/Parsing/DoxygenCommandParserTests.swift

@@ -469,7 +469,9 @@ class DoxygenCommandParserTests: XCTestCase {
         let expectedDump = #"""
         Document
         ├─ BlockDirective name: "method"
-        ├─ BlockDirective name: "abstract"
+        ├─ DoxygenAbstract
+        │  └─ Paragraph
+        │     └─ Text "Some brief description of this method"
         ├─ DoxygenParameter parameter: number
         │  └─ Paragraph
         │     └─ Text "Some description of the “number” parameter"

Tests/MarkdownTests/Visitors/MarkupFormatterTests.swift

@@ -301,6 +301,26 @@ class MarkupFormatterSingleElementTests: XCTestCase {
         XCTAssertEqual(expectedAt, printedAt)
     }
 
+    func testPrintDoxygenAbstract() {
+            let expected = #"\abstract Another thing."#
+            let printed = DoxygenAbstract(children: Paragraph(Text("Another thing."))).format()
+            print (printed)
+            XCTAssertEqual(expected, printed)
+    }
+
+    func testPrintDoxygenAbstractMultiline() {
+        let expected = #"""
+        \abstract Another thing.
+        This is an extended abstract.
+        """#
+        let printed = DoxygenAbstract(children: Paragraph(
+            Text("Another thing."),
+            SoftBreak(),
+            Text("This is an extended abstract.")
+        )).format()
+        XCTAssertEqual(expected, printed)
+    }
+
     func testPrintDoxygenDiscussion() {
         let expected = #"\discussion Another thing."#
         let printed = DoxygenDiscussion(children: Paragraph(Text("Another thing."))).format()