In OS X native text editing apps provide information about the edited text using the accessibility methods. It allows other application to communicate with the application.
Currently Sublime Text does not support anything like that. Including the beta version.
Here is an example. On the screenshot, there is TextMate (popular programmer editor) window and Accessibility Inspector (displays information provided by other applications using accessibility).
The most interesting values are AXValue (editing content) and AXSelectedTextRange (range of the selected text.)
