Add markdown output format

Author: ileitch

CHANGELOG.md

@@ -7,6 +7,7 @@
 ##### Enhancements
 
 - Added `--write-results <file>` option.
+- Added `markdown` output format.
 
 ##### Bug Fixes
 

Sources/BUILD.bazel

@@ -158,6 +158,7 @@ swift_library(
         "PeripheryKit/Results/CsvFormatter.swift",
         "PeripheryKit/Results/GitHubActionsFormatter.swift",
         "PeripheryKit/Results/JsonFormatter.swift",
+        "PeripheryKit/Results/MarkdownFormatter.swift",
         "PeripheryKit/Results/OutputDeclarationFilter.swift",
         "PeripheryKit/Results/OutputFormatter.swift",
         "PeripheryKit/Results/XcodeFormatter.swift",

Sources/Configuration/OutputFormat.swift

@@ -7,6 +7,7 @@ public enum OutputFormat: String, CaseIterable {
     case checkstyle
     case codeclimate
     case githubActions = "github-actions"
+    case markdown
 
     public static let `default` = OutputFormat.xcode
 

Sources/PeripheryKit/Results/MarkdownFormatter.swift

@@ -0,0 +1,30 @@
+import Configuration
+import SystemPackage
+
+final class MarkdownFormatter: OutputFormatter {
+    let configuration: Configuration
+    lazy var currentFilePath: FilePath = .current
+
+    init(configuration: Configuration) {
+        self.configuration = configuration
+    }
+
+    func format(_ results: [ScanResult], colored: Bool) throws -> String? {
+        guard !results.isEmpty else {
+            return "No unused code detected."
+        }
+
+        let formattedResults = results.flatMap { result in
+            describe(result, colored: colored).map { location, description in
+                "| \(locationDescription(location)) | \(description) |"
+            }
+        }
+        .joined(separator: "\n")
+
+        return """
+        | Location | Result |
+        | :- | :- |
+        \(formattedResults)
+        """
+    }
+}

Sources/PeripheryKit/Results/OutputFormatter.swift

@@ -110,6 +110,8 @@ public extension OutputFormat {
             CheckstyleFormatter.self
         case .githubActions:
             GitHubActionsFormatter.self
+        case .markdown:
+            MarkdownFormatter.self
         }
     }
 }