AppleScript: The Definitive Guide

Using Terms From

A terms block (as I call it) has the following structure:

using terms from application
        -- code
end using terms from

A terms block dictates what application’s dictionary AppleScript should get the enclosed terminology from, without actually targeting that application. On the usual principle that the innermost block takes precedence, if multiple terms blocks are nested, only the innermost terms block containing a given line of code has any effect on that line. Similarly, a terms block overrides the dictionary-seeking function of an enclosing tell block. A terms block doesn’t override an enclosed tell, but if an enclosed tell would not permit AppleScript to obtain a dictionary that it needs, a terms block may do so.

Thus, this will not compile:

tell application "Finder"
        using terms from application "Mailsmith"
                get name of folder 1 -- compile-time error
        end using terms from
end tell

The problem there is that AppleScript must seek folder in Mailsmith’s dictionary, and doesn’t find it. But this will compile:

using terms from application "Finder"
        tell application someVariable
                get name of folder 1
        end tell
end using terms from

AppleScript has no idea what someVariable will be at runtime, so it follows the instructions of the terms block and thus is able at compile time to obtain a dictionary that resolves the enclosed terminology. This, however, does not guarantee that the code will run. Perhaps someVariable will specify an application that knows what a folder is; perhaps ...