CocoaConf DC - Automate with Swift - Tony Ingraldi

Automate with Swift
CocoaConf DC, April 10, 2015
Tony Ingraldi
GitHub: tingraldi • Twitter: @TonyIngraldi

Itinerary
• Motivation: Why Automate?
• A bit of history
• Why Swift?
• Nuts and bolts

Show of Hands?
• Have you used…
• AppleScript?
• Automator?
• Other form of application scripting?

Why Automate?
• Improve productivity
• Avoid repetitive tasks
• Streamline workﬂows
• Opportunities for experimentation
• Add missing features to OS X apps!

Open Scripting Architecture
• Introduced way back in October 1993
• The state of the Mac looked like this
Beige!

Open Scripting Architecture
• Survived the transition to OS X
• Leveraged by OS X to launch applications, open
documents, etc.
• A standard mechanism for interapplication
communication

Language Options
• AppleScript (there from the beginning)
• JavaScript for Automation (as of Yosemite)
• Python (PyObjC, py-appscript)
• Ruby (RubyCocoa, RubyOSA)
• And now Swift!

AppleScript
• A “natural language” programming model
• Primarily geared toward being the “glue”
between apps
• Limited inherent functionality

AppleScript
• Can be frustrating to people who are ﬂuent in
“normal” programming languages
• Verbosity is a hallmark
set fileName to "name.jpg"
set sansExtension to text 1 thru ((offset of "." in fileName) - 1) of fileName

Swift
• A “primary” language
• Ready access to Cocoa
• Can run Swift scripts using #! convention
• A familiar coding style
let fileName = "name.jpg"
let sansExtension = fileName.stringByDeletingPathExtension

Scripting Bridge
• Introduced in Mac OS X Leopard (version 10.5)
• Provides high-level Objective-C access to
scriptable applications
• Can be leveraged in Swift, with a bit of extra
work

Scripting Bridge Recipe
• 1 part sdef
• 1 part sdp
• A pinch of manual intervention
• Automate to taste

Scripting Deﬁnition
• Scriptable applications include resources that
describe their scripting interface
• Can be in a variety of forms
• The sdef command-line utility extracts the
scripting deﬁnition
• Writes to standard output in XML format

• Using sdef
sdef /path/to/App.app > App.sdef
• For the most part, using sdef is “run and forget”
• Until you ﬁnd out what’s wrong when you run sdp
• Some sdp warnings can be ignored

• Using sdp
sdp -fh --basename App App.sdef

Kicking the Tires
• Xcode
• Swift and ObjC command line targets
• Includes the header generated by sdp
• Experiment in main.swift and main.m

Demo
Kicking the tires in Xcode

Don’t Run with Scissors
• Using Objective-C header leads to pervasive
AnyObject typing
• Works, but can lead to ambiguity
• For properties, sometimes have to resort to
using valueForKey
• Sometimes leads to awkward method
invocation

An Alternative
• Create Swift protocols that cover the generated
Objective-C API
• 👍 Supports rich set of types
• 👍 API translation can be automated
• 👎 Requires optional declaration of all
properties and methods

Objective-C Excerpt
@interface AcornApplication : SBApplication
@property (copy, readonly) NSString *name;
- (SBElementArray *) windows;
- (NSString *) taunt;
@end

SBObject
@objc public protocol SBObjectProtocol:
NSObjectProtocol {
func get() -> AnyObject!
}

SBApplication
@objc public protocol SBApplicationProtocol:
SBObjectProtocol {
func activate()
var delegate:SBApplicationDelegate! { get set }
}

Application Protocol
@objc public protocol AcornApplication:
SBApplicationProtocol {
optional var name: String { get }
optional func windows() -> SBElementArray
optional func taunt() -> String
}
extension SBApplication : AcornApplication {}

Putting it Together
import ScriptingBridge
@objc public protocol AcornApplication : … {…}
let acorn = SBApplication
.applicationWithBundleIdentifier(
“com.flyingmeat.Acorn4"
) as! AcornApplication
acorn.taunt!()

Plan of Attack
• Create frameworks for target applications
• Install in /Library/Frameworks
• Write scripts instead of compiled code

By the Way
• Playgrounds don’t ﬁt well
• The Swift REPL could spontaneously combust at
any moment
• What’s a scripter to do?
• Use a text editor
• Edit, run, repeat

Script Invocation
• Hash-bang on the ﬁrst line
#!/usr/bin/xcrun swift -F /Library/Frameworks
• chmod +x SomeScript.swift

A Little Help
https://github.com/tingraldi/SwiftScripting
• Header conversion utilities
• Sample Application Scripting Frameworks
• Sample Scripts
• Scripting Utilities Framework

A Little More Help
@objc public protocol AcornApplication {…}
"com.flyingmeat.Acorn4"
acorn.taunt!()

A Little More Help
import AcornScripting // Acorn Swift protocols
"com.flyingmeat.Acorn4"
acorn.taunt!()

A Little More Help
import ScriptingUtilities // Helper framework
import AcornScripting // Acorn Swift protocols
let acorn = Application(name: "Acorn")
as! AcornApplication
acorn.taunt!()

Where to Put Scripts?
• Short answer: anywhere
• Some applications have special script folders
• Scripting Menu
• Invoke via an Automator Service

Summary
• Automate for productivity
• Add “missing features”
• Reinforce/leverage Swift expertise

CocoaConf DC - Automate with Swift - Tony Ingraldi

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