Brief Explanation Please

Question

Hello,
I was recently given some good advise here pertaining to a script. In case you don't check the link I do not need a workable script here, that has been taken care of but thank you anyway (is not necessary to answer this question).
https://discussions.apple.com/message/26354845#26354845
However, I understand the change in the dictionary portion of QuickTime Player I am still unclear as to why there is a specifier error with the fixes that I came up with myself. Could someone explain to me please why there is a specifier error with this script;
set this_sound to (((path to folder from System domain) as string) & "Sounds:Submarine.aiff") as alias
tell app "QuickTime Player"
open this_sound
set close after completion of document 1 to true
play document 1
end tell
Hope you all have a great day!
dofromon

Answer 1

Hello
Just for the record, there has never been a property named "close after completion" of "movie" object or "document" object in QuickTime Player (7 or X).
In QuickTime Player 7, there're "close when done" and "quit when done" properties of "document" object, which is indeed "movie" object.
In QuickTime Player 7, the term "movie" is defined as synonym for "document" in its AppleScript dictionary (this synonym definition is hidden in aete resource), that is why the term "movie" in source code in context of QuickTime Player 7 is compiled as "document" in AppleScript editor.
And the reason why the expression such as:
set close after completion of document 1 to true
does not throw compilation error in context of QuickTime Player X is that AppleScript compiler parses it NOT as
(set
    ("close after completion"
        (of (document (1))))
    (to (true)))
but as
(set
    (close
        (after
            (completion
                (of (document (1))))))
    (to (true)))
where
(close (after (completion (of (document (1))))))
is interpreted as
(close ("insertion point" (after (completion (of (document (1)))))))
and this (close ...) construct is expected to return something to be set to true.
Of course this should fail at run-time with various reasons, which include the said coercion error (provided that "completion" is not mere user variable name but defined as constant in QuickTime Player X), but compiler doesn't care and happily yields a non-sense byte-code.
Hope this may help you understand the situation better,
H