获取 applescript 文件的当前路径

想执行一段脚本，对该文件内的内容进行操作。所以需要知道当前路径。

tell application "Xcode"
    set CurrentActiveDocument to document 1 whose name ends with (word -1 of (get name of   window 1))
    set WhatYouWant to path of CurrentActiveDocument
end tell