A script text file
is exactly that: it's an ordinary text file, such as can be opened by any word processor, consisting of the uncompiled text of your script. Any script editor application will typically offer an option for saving a script as text. No bytecode is saved into the file, and the script need not be capable of compilation in order to be saved as text—as opposed to a compiled script file
, which by definition can't be saved unless the script can be compiled. (Apple's Script Editor does also attempt to compile the script when you save it as text, and will report any compilation errors even though saving succeded; this seems like a bug.) The conventional extension for a script text file on Mac OS X is .applescript, but it is still of type 'TEXT'.
Most script runners will refuse to execute a script text file; they generally expect a compiled script file, whereas a script text file is not compiled (and the script runner is not willing to do the compilation).
A script text file is described by Apple's documentation as a kind of low-grade, last-resort alternative to a compiled script file. But it does have certain advantages. For one thing, obviously, you can save it even though you can't compile the script, so if you're developing a script that won't compile or that you'd rather not compile just now, you have a way to save it. Also there are matters of compatibility and portability. Recall that Apple's Script Editor can't create a compiled script file that will work on early versions of Mac OS 9 or before. And (as I'll discuss later in this chapter) a compiled script file can face difficulties if AppleScript can't locate a needed external referent, which can happen particularly when the script is moved to another computer. A script text file overcomes all these difficulties; it's just text, and therefore is absolutely portable to any machine running any system. Some version of AppleScript and the Script Editor will be present on just about any machine running Mac OS, so the file can be opened and, if the code is valid, the script can be compiled there.
A valuable feature of Script Debugger is that it saves the original text (as a resource) even into a compiled script file. It's like having two files in one, a compiled script file and a script text file, with all the advantages of both. If there's a problem with the compiled script file (for example, if external referents can't be located or are incorrectly identified by AppleScript), the script text can still be recovered.