AppleScript for the rest of us

Of all the programming languages I have learned, there are two that have consistently made me feel stupid.

Prolog and AppleScript.

At least with Prolog, I found I could provide it with enough random facts and it would eventually barf back an answer of ‘yes’ for whether or not my assignment was done. And, of course, Prolog has good jokes (thanks, Ray!):

Q: How many prolog programmers does it take to change a light bulb?
A: No.

AppleScript, on the other hand, continues to baffle me. All those english like sentences just confuse me. I constantly try to write code that is, well, like code and it doesn’t work.

Fortunately, there is appscript, a python module that makes any AppleScriptable application into something I can talk to just like any other Python object. This quite effectively reduces AppleScript programming to a programming exercise that my tiny little mind can effectively metabolize.

Furthermore, I can use appscript from within the command line interpreter (read this first to make sure the command line python interpreter is actually useful).

While grabbing appscript, you might also want to download HTMLDictionary. It dumps an appscript compatible HTML document describing any random application’s scripting dictionary.

After installing appscript, fire up the python interpreter and grab a reference to the iTunes application (yes, start it with pythonw — appscript requires a windowmanager connection):

[albbum:~] bbum% pythonw
Python 2.3.5 (#1, Jan 13 2006, 20:13:11) 
[GCC 4.0.1 (Apple Computer, Inc. build 5250)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import appscript
>>> iTunes = appscript.app("iTunes")
>>> print iTunes
app(u'/Applications/iTunes.app')

Great! Now what?

Fortunately, appscript has a built in help() command that will answer exactly that question:

>>> iTunes.help()
================================================================================
Appscript Help (-t)

Reference: app(u'/Applications/iTunes.app') 

-------------------------------------------------------------------------------- 
Description of reference

Terminology for application class

Class: application -- The application program 
    Properties: 
        current_encoder : k.encoder -- the currently selected encoder (MP3, AIFF, WAV, etc.) 
        current_EQ_preset : k.EQ_preset -- the currently selected equalizer preset 
        current_playlist : k.playlist (r/o) -- the playlist containing the currently targeted track 
.....
        visual_size : k.small | k.medium | k.large -- the size of the displayed visual 
    Elements: 
        browser_windows -- index | name | id 
....
        windows -- index | name | id 

================================================================================ 
app(u'/Applications/iTunes.app')

Oddly, help() doesn’t seem to show the commands available on the application reference. Fortunately, HTMLDictionary does.

Now I can can poke around the library a bit:

>>> pl = iTunes.playlists[3]
>>> for p in iTunes.playlists():
...   print p.name()
... 
Library
Party Shuffle
Purchased
90’s Music
My Top Rated
Recently Added
Recently Played
Top 25 Most Played
Videos
burny burny
Podcasts

Including diving all the way down to the tracks:

>>> for t in pl.tracks():
...   print t.name()
... 
Munich
Who Will Love Me Now (Jimmy Gomez Mix)
Cover Me (Trouser Enthusiasts Remix)
Change (Angelic Remix)
....

You get the idea. There are tons of cool things that could be done with this tool in hand. Obviously, combining AppleScript with something like Twisted to build a network enabled gateway to your desktop.

Or you could use PyObjC to build standard Cocoa apps that interact with other apps via AppleScript directly in your app’s code. Of course, this would allow access to any random framework on the system either through the Objective-C APIs directly from Python or by compiling simple wrapper classes in Obj-C around any C or C++ API.

Fun.

This entry was posted on Friday, March 24th, 2006 at 1:31 am and is filed under Mac OS X, Software, Technology. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.