Set up diff command line inputs.

Author: emilyychenn

Sources/SwiftDocCUtilities/ArgumentParsing/Subcommands/Diff.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 ArgumentParser
+import Foundation
+import SwiftDocC
+
+extension Docc.ProcessArchive {
+    struct Diff: ParsableCommand {
+        
+        // MARK: - Configuration
+        
+        static var configuration = CommandConfiguration(
+            commandName: "diff",
+            abstract: "Produce the symbol diff between two Render JSON files.",
+            shouldDisplay: true)
+        
+        // MARK: - Command Line Options & Arguments
+        
+        @Argument(
+            help: ArgumentHelp(
+                "The path to a Render JSON file to be compared.",
+                valueName: "renderJSON1"),
+            transform: URL.init(fileURLWithPath:))
+        var firstRenderJSON: URL
+        
+        @Argument(
+            help: ArgumentHelp(
+                "The path to a second Render JSON file to be compared.",
+                valueName: "renderJSON2"),
+            transform: URL.init(fileURLWithPath:))
+        var secondRenderJSON: URL
+        
+        // MARK: - Execution
+        
+        public mutating func run() throws {
+            let firstRenderJSONData = try Data(contentsOf: firstRenderJSON)
+            let secondRenderJSONData = try Data(contentsOf: secondRenderJSON)
+            
+            let decoder = RenderJSONDecoder.makeDecoder()
+            let firstRenderNode = try decoder.decode(RenderNode.self, from: firstRenderJSONData)
+            let secondRenderNode = try decoder.decode(RenderNode.self, from: secondRenderJSONData)
+            
+            let difference = firstRenderNode._difference(from: secondRenderNode)
+            print(difference)
+        }
+        
+    }
+}

Sources/SwiftDocCUtilities/ArgumentParsing/Subcommands/ProcessArchive.swift

@@ -18,7 +18,7 @@ extension Docc {
         static var configuration = CommandConfiguration(
             commandName: "process-archive",
             abstract: "Perform operations on documentation archives ('.doccarchive' directories).",
-            subcommands: [TransformForStaticHosting.self, Index.self])
+            subcommands: [TransformForStaticHosting.self, Index.self, Diff.self])
 
     }
 }