Add preceding newlines before Doxygen commands

Author: a7medev

Sources/Markdown/Walker/Walkers/MarkupFormatter.swift

@@ -1174,27 +1174,47 @@ public struct MarkupFormatter: MarkupWalker {
     }
 
     public mutating func visitDoxygenDiscussion(_ doxygenDiscussion: DoxygenDiscussion) {
+        if doxygenDiscussion.indexInParent > 0 {
+            ensurePrecedingNewlineCount(atLeast: 2)
+        }
+
         printDoxygenStart("discussion", for: doxygenDiscussion)
         descendInto(doxygenDiscussion)
     }
 
     public mutating func visitDoxygenAbstract(_ doxygenAbstract: DoxygenAbstract) {
+        if doxygenAbstract.indexInParent > 0 {
+            ensurePrecedingNewlineCount(atLeast: 2)
+        }
+
         printDoxygenStart("abstract", for: doxygenAbstract)
         descendInto(doxygenAbstract)
     }
 
     public mutating func visitDoxygenNote(_ doxygenNote: DoxygenNote) {
+        if doxygenNote.indexInParent > 0 {
+            ensurePrecedingNewlineCount(atLeast: 2)
+        }
+
         printDoxygenStart("note", for: doxygenNote)
         descendInto(doxygenNote)
     }
 
     public mutating func visitDoxygenParameter(_ doxygenParam: DoxygenParameter) {
+        if doxygenParam.indexInParent > 0 {
+            ensurePrecedingNewlineCount(atLeast: 2)
+        }
+
         printDoxygenStart("param", for: doxygenParam)
         print("\(doxygenParam.name) ", for: doxygenParam)
         descendInto(doxygenParam)
     }
 
     public mutating func visitDoxygenReturns(_ doxygenReturns: DoxygenReturns) {
+        if doxygenReturns.indexInParent > 0 {
+            ensurePrecedingNewlineCount(atLeast: 2)
+        }
+
         // FIXME: store the actual command name used in the original markup
         printDoxygenStart("returns", for: doxygenReturns)
         descendInto(doxygenReturns)

Tests/MarkdownTests/Visitors/MarkupFormatterTests.swift

@@ -1626,4 +1626,31 @@ class MarkupFormatterMixedContentTests: XCTestCase {
         ]
         zip(expected, printed).forEach { XCTAssertEqual($0, $1) }
     }
+
+    func testDoxygenCommandsWithPrecedingNewlines() {
+        let expected = #"""
+            Does something.
+
+            \abstract abstract
+
+            \param x first param
+
+            \returns result
+
+            \note note
+
+            \discussion discussion
+            """#
+
+        let printed = Document(
+            Paragraph(Text("Does something.")),
+            DoxygenAbstract(children: Paragraph(Text("abstract"))),
+            DoxygenParameter(name: "x", children: Paragraph(Text("first param"))),
+            DoxygenReturns(children: Paragraph(Text("result"))),
+            DoxygenNote(children: Paragraph(Text("note"))),
+            DoxygenDiscussion(children: Paragraph(Text("discussion")))
+        ).format()
+
+        XCTAssertEqual(expected, printed)
+    }
 }