Updated README

README.md

@@ -2,15 +2,16 @@
 
 ![Icon](http://johnholdsworth.com/Syringe_128.png)
 
-This start-over implementation on [Injection for Xcode](https://github.com/johnno1962/injectionforxcode)
-has been built into an app: InjectionIII.app included in the repo which runs in the status bar.
 Code injection allows you to update the implementation of methods of a class incrementally
-in the iOS simulator without having to rebuild or restart your application saving developer time.
-You can avoid code signing complications by using the binary from the mac app store.
- Injection also expects to find your current Xcode at path /Appplications/Xcode.app.
-Finally, you'll need to add one of the following to your application's applicationDidFinishLaunching:
+in the iOS simulator without having to rebuild or restart your application saving the developer a significant amount of time.
+This start-over implementation of [Injection for Xcode](https://github.com/johnno1962/injectionforxcode)
+has been built into a standalone app: `InjectionIII.app` which runs in the status bar and is [available from the Mac App Store](https://itunes.apple.com/app/injectioniii/id1380446739?mt=12).
 
-Xcode 10.2 and later:
+`InjectionII.app` expects to find your current Xcode at path `/Applications/Xcode.app` , works for `Swift` and `Objective-C` and can be used with [AppCode](https://www.jetbrains.com/objc/features/swift.html) but you need to have built your project using Xcode first to provide the logs used to determine how to compile the project.
+
+To use injection, download and run the app then all you need to add one of the following to your application delegate's `applicationDidFinishLaunching:`
+
+Xcode 10.2 and later (Swift 5+):
 
 ```Swift
 #if DEBUG
@@ -21,7 +22,7 @@ Bundle(path: "/Applications/InjectionIII.app/Contents/Resources/tvOSInjection.bu
 Bundle(path: "/Applications/InjectionIII.app/Contents/Resources/macOSInjection.bundle")?.load()
 #endif
 ```
-Xcode 10.1:
+Xcode 10.1 (Swift 4.2):
 
 ```Swift
 #if DEBUG
@@ -33,51 +34,82 @@ Bundle(path: "/Applications/InjectionIII.app/Contents/Resources/macOSInjection10
 #endif
 ```
 
-Once injection is connected, a file watcher is started in the InjectionIII app and whenever
-you save a Swift or Objective-C source the target app is messaged to update the implementation.
-The file watcher can be disabled & enabled while the app is running using the status bar menu.
-While the file watcher is disabled you can force injection's through manually using a hotkey ctrl-=.
-If you inject a subclass of XCTest it will try running that individual test inside your application.
+Adding one of these lines loads a bundle included in the `InjectionIII.app`'s
+resources which connects over a local socket to the macOS app.
+Once injection is connected, you'll be prompted to select the project directory for the app you wish to inject. This starts a `file watcher` in the Mac app and whenever
+you save a Swift (or Objective-C) source in the project, the target app is messaged through the socket to compile, link, dynamically load and update the implementation of _classes_ in the file being injected. 
+The file watcher can be disabled & enabled while the app is running using the status bar menu and
+if the file watcher is disabled you can still force injections through manually using a hotkey `ctrl-=` (remember to save the file first!)
+If you inject a subclass of `XCTest` it will try running that individual test inside your application provided it does not require test specific support code,
 When you run your application without rebuilding (^⌘R), recent injections will be re-applied.
 
-Included is a manual implementation of ["code injection"](InjectionBundle/SwiftInjection.swift).
-If you are stopped in a class, you can edit the class' implementation, save it and type
-"p inject()". Your changes will be applied without having to restart the application.
-To detect this in your code to reload a view controller for example, add an @objc
-injected() method or subscribe to the `"INJECTION_BUNDLE_NOTIFICATION"`.
+If you get an error from the compiler saying your source file is not found this is typically due to upper/lower case differences as in injection filenames are case sensitive. The easiest way to resolve this is to remove and re-add the file concerned to your project and rebuild. 
+
+To detect when a class has been injected in your code (to reload a view controller for example) add an `@objc func
+injected()` class or instance method. The instance `@objc
+func injected()` method relies on a "sweep" of all objects in your application to find those of
+the class you have just injected which can be unreliable using `unowned` instance variables in particular. If you encounter problems, subscribe to the `"INJECTION_BUNDLE_NOTIFICATION"` instead.
 
 Included in this release is "Xprobe" which allows you to browse the objects in
-you application as a graph and execute code against them. If you want to build
+you application through a web-like interface and execute code against them.
+
+If you want to build this project
 from source you'll need to use:
 
  git clone https://github.com/johnno1962/InjectionIII --recurse-submodules
 
 ### Available downloads
 
-| Xcode 10.1, Xcode 10.2* |
+| Xcode 10.1, Xcode 10.2+ |
 | ------------- |
 | [Mac app store](https://itunes.apple.com/app/injectioniii/id1380446739?mt=12) |
 
 ### Limitations
 
 To work, [method dispatch](https://www.raizlabs.com/dev/2016/12/swift-method-dispatch/)
-must be through the classes "vtable" and not be "direct" i.e. statically linked. This means
-injection will not work for final methods or methods in final classes or structs. The `@objc
-func injected()` method relies on a sweep of all objects in your application to find those of
-the class you have just injected which can fail. If you encounter problems, use the notification.
+must be through the class' "vtable" and not be "direct" i.e. statically linked. This means
+injection will not work for final methods or methods in final classes or structs. Injecting a file containing protocol definitions will likely not work.
+
+The App Tracing functionality uses the trampoline implementation from [
 
 If you are using Code Coverage, you will need to disable it or you may receive a:
 > `Symbol not found: ___llvm_profile_runtime` error.`
 
 Go to `Edit Scheme -> Test -> Info -> Code Coverage` and (temporarily) disable.
 
-Be mindful of global state -- If the file you're injecting as non instance-level variables e.g. singletons
-they will be reset when you inject the code as the new implementations will refer to the newly loaded
+Be mindful of global state -- If the file you're injecting as non instance-level variables e.g. singletons, static or global vars
+they will be reset when you inject the code as the new method implementations will refer to the newly loaded
 version of the class.
 
 As injection needs to know how to compile swift files individually it is incompatible with building using
-whole module optimisation. A workaround for this is to build with WMO switched off so there are
-logs of individual compiles then switching it back on if it suits your project best.
+`Whole Module Optimisation`. One workaround for this is to build with `WMO` switched off so there are
+logs of individual compiles available then switching `WMO` back on if it suits your project better.
+
+### Storyboard injection
+
+Sometimes when you are iterating over a UI it is useful to be able to inject storyboards. This works slightly differently from code injection. To inject changes to a storyboard scene, make you changes than build the project instead of saving the storyboard. The "nib" of the currently displayed view controlled should be reloaded and viewDidLoad etc. will be called.
+
+### SwiftUI injection
+
+Single file SwiftUI interfaces can be injected to give you an interactive preview experience even if you don't have `macOS Catalina` installed. First, you need to add one of the bundle loading commands above to your AppDelegate. Then, add the following to the #if DEbUD'd preview section of the SwiftUI file you are injecting:
+
+```Swift
+class Refresher {
+ @objc class func injected() {
+ UIApplication.shared.windows.first?.rootViewController =
+ UIHostingController(rootView: ContentView())
+ }
+}
+```
+`ContentView()` in this code needs to be replaced with the same initial view as is used in your `SceneDelegate.swift` to initialise the `UIHostingController`. Even though ContentView is a struct and is therefore statically liked, if it is defined in the file being injected containing the `Refresher` class, the new implementation will take precedence when the interface reloads.
+
+### Vaccine
+
+Injection now includes the higher level `Vaccine` functionality, for more information consult the [project README](https://github.com/zenangst/Vaccine) or one of the [following](https://medium.com/itch-design-no/code-injection-in-swift-c49be095414c) [references](https://medium.com/@robnorback/the-secret-to-1-second-compile-times-in-xcode-9de4ec8345a1).
+
+### App Tracing
+
+The InjectionIII menu contains an item "Trace (Beta)" which can be used to enable logging of all Objective-C and non-final class method calls. This feature is experimental. Selecting the menu item again will turn the feature back off.
 
 ## SwiftEval - Yes, it's eval() for Swift
 
@@ -116,7 +148,7 @@ An example of how it is used can be found in the EvalApp example.
  }
 ```
 
-### implementation
+### eval() implementation
 
 The code works by adding an extension to your class source containing the expression.
 It then compiles and loads this new version of the class "swizzling" this extension onto
@@ -135,6 +167,8 @@ This project includes code from [rentzsch/mach_inject](https://github.com/rentzs
 [davedelong/DDHotKey](https://github.com/davedelong/DDHotKey) under their
 respective licenses.
 
+The App Tracing functionality uses the [OliverLetterer/imp_implementationForwardingToSelector](https://github.com/OliverLetterer/imp_implementationForwardingToSelector) trampoline implementation via the [SwiftTrace](https://github.com/johnno1962/SwiftTrace) project under an MIT license.
+
 This release includes a very slightly modified version of the excellent
 [canviz](https://code.google.com/p/canviz/) library to render "dot" files
 in an HTML canvas which is subject to an MIT license. The changes are to pass