Add delete highlights

Sources/SwiftDocC/Model/Rendering/References/FileReference.swift

@@ -39,6 +39,9 @@ public struct FileReference: RenderReference, Equatable {
  /// The line highlights for this file.
  public var highlights: [LineHighlighter.Highlight] = []
 
+ /// The delete line highlights for this file.
+ public var deleteHighlights: [LineHighlighter.Highlight] = []
+
  /// Creates a new file reference.
  ///
  /// - Parameters:
@@ -54,14 +57,16 @@ public struct FileReference: RenderReference, Equatable {
  fileType: String,
  syntax: String,
  content: [String],
- highlights: [LineHighlighter.Highlight] = []
+ highlights: [LineHighlighter.Highlight] = [],
+ deleteHighlights: [LineHighlighter.Highlight] = []
  ) {
  self.identifier = identifier
  self.fileName = fileName
  self.fileType = fileType
  self.syntax = syntax
  self.content = content
  self.highlights = highlights
+ self.deleteHighlights = deleteHighlights
  }
 
  public init(from decoder: Decoder) throws {
@@ -73,6 +78,7 @@ public struct FileReference: RenderReference, Equatable {
  syntax = try values.decode(String.self, forKey: .syntax)
  content = try values.decode([String].self, forKey: .content)
  highlights = try values.decodeIfPresent([LineHighlighter.Highlight].self, forKey: .highlights) ?? []
+ deleteHighlights = (try? values.decodeIfPresent([LineHighlighter.Highlight].self, forKey: .deleteHighlights)) ?? []
  }
 }
 

Sources/SwiftDocC/Model/Rendering/RenderNodeTranslator.swift

@@ -129,6 +129,7 @@ public struct RenderNodeTranslator: SemanticVisitor {
  // Add the highlights to the file references.
  for result in highlightsPerFile {
  fileReferences[result.file.path]?.highlights = result.highlights
+ fileReferences[result.file.path]?.deleteHighlights = result.deleteHighlights
  }
 
  return TutorialSectionsRenderSection.Section(title: tutorialSection.title, contentSection: introduction, stepsSection: stepsContent, anchor: urlReadableFragment(tutorialSection.title))

Sources/SwiftDocC/Model/Rendering/Tutorial/LineHighlighter.swift

@@ -56,6 +56,9 @@ public struct LineHighlighter {
 
  /// The highlights to apply when displaying this file.
  let highlights: [Highlight]
+
+ /// The delete highlights to apply when displaying this file.
+ let deleteHighlights: [Highlight]
  }
 
  /**
@@ -121,7 +124,7 @@ public struct LineHighlighter {
  private func lineHighlights(old: ResourceReference, new: ResourceReference) -> Result {
  // Retrieve the contents of the current file and the file we're comparing against.
  guard let oldLines = lines(of: old), let newLines = lines(of: new) else {
- return Result(file: new, highlights: [])
+ return Result(file: new, highlights: [], deleteHighlights: [])
  }
 
  let diff = newLines.difference(from: oldLines)
@@ -134,22 +137,29 @@ public struct LineHighlighter {
  return Highlight(line: offset + 1)
  }
 
- return Result(file: new, highlights: highlights)
+ let deleteHighlights = diff.removals.compactMap { removal -> Highlight? in
+ guard case .remove(let offset, _, _) = removal else { return nil }
+ // Use 1-based indexing for line numbers.
+ // TODO: Collect intra-line diffs.
+ return Highlight(line: offset + 1)
+ }
+
+ return Result(file: new, highlights: highlights, deleteHighlights: deleteHighlights)
  }
 
  /// Returns the line highlights between two ``Code`` elements.
  private func lineHighlights(old: Code?, new: Code) -> Result {
  if let previousFileOverride = new.previousFileReference {
  guard !new.shouldResetDiff else {
- return Result(file: new.fileReference, highlights: [])
+ return Result(file: new.fileReference, highlights: [], deleteHighlights: [])
  }
  return lineHighlights(old: previousFileOverride, new: new.fileReference)
  }
 
  guard let old = old,
  old.fileName == new.fileName,
  !new.shouldResetDiff else {
- return Result(file: new.fileReference, highlights: [])
+ return Result(file: new.fileReference, highlights: [], deleteHighlights: [])
  }
 
  return lineHighlights(old: old.fileReference, new: new.fileReference)