rb-appscript

4. Getting Help

When developing appscript-based scripts, there are several ways to get information about applications' scripting interfaces: the ASDictionary application, appscript's powerful built-in help method, and introspection.

ASDictionary

ASDictionary, available from the appscript website's Tools page, provides a convenient GUI interface for exporting application terminology resources in plain text and HTML formats. ASDictionary can export HTML dictionaries in both single-file format and a frame-based format similar to rdoc's.

Built-in help method

Appscript's Application and Reference classes include a powerful interactive help system that allows you to explore applications' scripting interfaces from within running scripts and Ruby's interactive irb interpreter. The help method can provide information on any suite, class, command or reference, and display the inheritance and relationships for a selected class or the entire application.

Note that rb-appscript's built-in help system is only available when ASDictionary 0.9.0 or later is installed. If ASDictionary isn't available or is too old, invoking help will simply result in a "No help available" message and the script will continue to run as normal.

Built-in help is invoked by calling an app object's help method, optionally passing it a string indicating the type of information you want. The resulting help message is printed to stderr and script execution continues as normal. For example, to view the help system's own help, call the help method with '-h' as its argument:

app('TextEdit').help('-h')

To print a description of any class or command or view inheritance and relationships, pass the help method a help string containing one or more of the following options:

-h
show help
-o
overview of all suites, classes and commands
-k
list all built-in keywords (type names)
-u [suite-name]
summary of named suite or all suites
-t [class-or-command-name]
terminology for named class/command or current reference
-i [class-name]
inheritance tree for named class or all classes
-r [class-name]
one-to-one and one-to-many relationships for named class or current reference
-s [property-or-element-name]
values of properties and elements of object(s) currently referenced

Arguments (shown in brackets) are optional. Additional information on usage is available via help('-h').

Examples:

app('Finder').help('-o')
app('Finder').help('-t window')
app('Finder').files.help # same as help('-t')
app('Finder').help('-d item -r folder -i container')
app('Finder').files.help('-s')

To print detailed information on a specific reference, call its help method without arguments. Examples:

app('TextEdit').help
app('TextEdit').version.help
app('TextEdit').documents.help

To print detailed information on a specific command, call the help method on an application or reference object with the -t option followed by the command's name. Examples:

app('TextEdit').help('-t open')
app('TextEdit').documents.help('-t count -t close')

Tip: help calls can safely be inserted at any point in a reference without disrupting your script's execution:

c = app('TextEdit').help.help('-o -i -s').documents.help[1].help.count

Introspection

In addition to supporting Ruby's standard #methods and #respond_to? methods, appscript's Application and Reference classes also define several instance methods for obtaining information on the target application:

properties
Returns a list of all property names.
elements
Returns a list of all element names.
commands
Returns a list of all command names.
keywords
Returns a list of all class, enumerator, type and property names.
parameters(commandName)
Takes a command's name as string and returns the names of its parameters.

As with Ruby's Object#methods, all of these methods return a list of strings.

Examples

te = app('TextEdit')

p te.commands
# ["activate", "close", "count", "delete", "duplicate", "exists", ...]

p te.parameters('make')
# ["at", "new", "with_data", "with_properties"]

ASTranslate

ASTranslate, available from the appscript website's tools page, provides a simple tool for translating application commands from AppleScript to Ruby syntax - useful when help is needed in converting existing AppleScript code to Ruby. For example, the following AppleScript selects every file in the Home folder:

tell application "Finder"
	select (every file of home whose name extension is in {"htm", "html"})
end tell

To obtain the appscript equivalent, paste this script into ASTranslate and select Execute from the Document menu. ASTranslate will intercept any Apple events sent by AppleScript and display them appscript format:

app("Finder").home.files[its.name_extension.is_in(["htm", "html"])].select

OK

See ASTranslate's documentation for more information.

Notes

While appscript's documentation systems try to be reasonably forgiving of flawed or faulty terminology resources, there may be a few particularly problematic applications on which they fail. Should this happen, use ASDictionary to export the application's terminology in plain text format instead.

Other sources of help