More doc for Swift target.

doc/swift-target.md

@@ -15,11 +15,44 @@ $ antlr4 -Dlanguage=Swift MyGrammar.g4
 For a full list of antlr4 tool options, please visit the [tool documentation page](tool-options.md).
 
 #### 3. Get the Swift ANTLR runtime
-You will find Swift runtime (framework project) in
 
-```
-antlr4/runtime/Swift 
-```
+Due to unstable ABI of Swift language, there will not be a single "library" for the Swift ANTLR runtime for now.
+
+The following instructions are assuming Xcode as the IDE:
+
+* __Create parser/lexer__. Make sure the parsers/lexers generated in __step 2__ are added to the project. To do this, you can drag
+the generated files from Finder to the Xcode IDE. Remember to check __Copy items if needed__ to make sure
+the files are actually moved into the project folder instead of symbolic links (see the screenshot below). After moving you will be
+able to see your files in the project navigator. But when you open one of the files, you will see Xcode 
+complaining the module "Antlr4" could not be found at the import statement. This is expected, since we still need the ANTLR Swift runtime for
+those missing symbols.
+
+<img src=images/dragfile.png>
+
+* __Download ANTLR runtime__. Clone the ANTLR repository. Open it in finder. From the root directory of the repo, go to runtime/Swift folder. You will be
+able to see the Xcode project manifest file: __Antlr4.xcodeproj__. 
+
+* __Import ANTLR Swift runtime into project__. Drag Antlr4.xcodeproj into your project, after this is done, your Xcode project navigator will be something
+like the screenshot below. In this case, your own project is "Smalltalk", and you will be able to see the Antlr4.xcodeproj
+shown as a contained project. 
+
+<img src=images/xcodenav.png>
+
+* __Build ANTLR runtime__. And by opening the "Products" folder in the inner project (Antlr4.xcodeproj), you will see
+two Antlr4.framework files. ".framework" file is the swift version of ".jar", ".a" as in JAVA, C/C++
+Initially those two files should be red, that's because they are not built. To build, click the "target selection" button
+right next to your Xcode run button. And in the drop down select the target you want to build. And you will see the two 
+Antlr4.framework files are for iOS and OSX. As shown below. After target selection, press "CMD+B", and Xcode will build
+the framework for you. Then you will see one of the frameworks become black.
+
+<img src=images/targetselection.png>
+
+** __Add dependencies__. Simply adding ANTLR Swift runtime and build the artifact is not enough. You still need to specify
+dependencies. Click your own project (Smalltalk), and you will see project setting page. Go to "Build Phase", and inside it
+make sure your ANTLR Swift runtime framework is added to both "__Target Dependencies__" and "__Link Binary With Libraries__"
+sections. As shown below.
+
+<img src=images/xcodedep.png>
 
 #### 4. Example playground