Use Swift's CommandLine for argc and argv

README.md

@@ -89,9 +89,9 @@ And include the Haskell stub header:
 ## Linking
 
 To link our Haskell library into our Swift app, we'll build it
-as a dynamic library and add it to our Xcode project. Building
-a static library is also possible, but currently requires
-[building your own GHC][pic-ghc].
+as a dynamic library and add it to our Xcode project. Building a
+static library is also possible, but currently requires
+[rebuilding the GHC standard libraries][pic-ghc].
 
 [pic-ghc]: https://github.com/lyokha/nginx-haskell-module#static-linkage-against-basic-haskell-libraries
 
@@ -162,23 +162,17 @@ to copy the libraries into the app bundle:
 ## Runtime Setup
 
 Before using functions from Haskell, we'll need to start its
-runtime. `hs_init` takes pointers to C's argc and argv, however
-since we aren't using command line arguments, we can just pass a
-constant array.
+runtime. `hs_init` takes pointers to C's argc and argv. In
+Swift, these are available as `CommandLine.argc` and
+`CommandLine.unsafeArgv`.
 
 Add this to your app delegate's `applicationDidFinishLaunching`
 method:
 
     func applicationDidFinishLaunching(_ aNotification: Notification) {
-        var argv0 = Array("SwiftHaskell".utf8CString)
-        argv0.withUnsafeMutableBufferPointer { argv0bp in
-            var argv = [argv0bp.baseAddress];
-            var argc = CInt(argv.count)
-            argv.withUnsafeMutableBufferPointer { argvbp in
-                var argvp = argvbp.baseAddress
-                hs_init(&argc, &argvp)
-            }
-        }
+        var argc = CommandLine.argc
+        var argv = Optional.some(CommandLine.unsafeArgv)
+        hs_init(&argc, &argv)
     }
 
 And the corresponding `hs_exit` to `applicationWillTerminate`:
@@ -187,8 +181,6 @@ And the corresponding `hs_exit` to `applicationWillTerminate`:
         hs_exit()
     }
 
-TODO: Explain swift pointer bits.
-
 ## Calling Haskell from Swift
 
 Add a new label to the window in `MainMenu.xib` for us to write

SwiftHaskell/AppDelegate.swift

@@ -15,15 +15,9 @@ class AppDelegate: NSObject, NSApplicationDelegate {
     @IBOutlet weak var label: NSTextField!
 
     func applicationDidFinishLaunching(_ aNotification: Notification) {
-        var argv0 = Array("SwiftHaskell".utf8CString)
-        argv0.withUnsafeMutableBufferPointer { argv0bp in
-            var argv = [argv0bp.baseAddress];
-            var argc = CInt(argv.count)
-            argv.withUnsafeMutableBufferPointer { argvbp in
-                var argvp = argvbp.baseAddress
-                hs_init(&argc, &argvp)
-            }
-        }
+        var argc = CommandLine.argc
+        var argv = Optional.some(CommandLine.unsafeArgv)
+        hs_init(&argc, &argv)
 
         label.stringValue = "\(square(5))"
     }