Utilities and samples to aid in using Swift with the Scripting Bridge
Generating Swift API for a Target Application
The scripting approach leveraged here is a Swift layer on top of the Scripting Bridge.
Xcode ships with a pair of utilities,
sdp, to aid Objective-C programmers in using the Scripting Bridge.
sdef tool is used to extract the scripting definition from an application. It emits the scripting
definition to standard output in XML format. The
sdp tool can be used to convert the XML emitted by
sdef to an Objective-C header file. This header file defines the scripting interface for a target application
exposed to Objective-C by the Scripting Bridge.
When scripting applications using Swift, it is possible to leverage the same Objective-C headers emitted by
However, due to the dynamically generated classes involved in realizing the Scripting Bridge interface, this approach
can be cumbersome and forces the use of
AnyObject types even in areas when more specific types are known to
The approach here is to generate a set of Swift protocols based on the Objective-C header emitted by
sdp. In most cases,
the generated file can be used without modification. There are some corner cases where manual editing is required to
correct issues or workaround bugs in the Swift compiler.
The basic recipe for generating the Swift protocols and enums for a fictitious application called App.app is as follows
sdef /Applications/App.app > App.sdef
sdp -fh --basename App App.sdef
Step 1 will create the
App.sdef file in the current directory. Step 2 will create a file
App.h, also in the current
directory. Step 3 will create
App.swift in the current directory. This is the primary file describing the scripting interface. The final step will create the file
AppScripting.swift which contains an enum with values appropriate for class creation.
Note that the sbhc.py script leverages the Python bindings for libclang.
You must install these bindings before running the script. You'll also need to install the Xcode command line tools (
See https://majestysoftware.wordpress.com/2015/03/31/swift-scripting-part-1/ for part one of a four-part series that gives a bit of explanation related to SwiftScripting.