[TxMt] Simple textmate applescripting question

[William Scott]

Hi:

I am trying to write a simple osascript command-line utility that  
acquires the directory of the file displayed in the frontmost  
TextMate editor window, and am having trouble.

I've been trying to use applescript syntax such as this:

osascript<< END
tell application "TextMate"
	activate
	do shell script "echo $TM_DIRECTORY"
end tell
END

but the variable $TM_DIRECTORY is apparently empty.

Is there another way to accomplish this, with or without  
applescripting? (I'd prefer a less pathological scripting language.)

Thanks.

Bill