Subj : Re: Function.toString - Silly Idea
To   : netscape.public.mozilla.jseng
From : Martin Honnen
Date : Fri Aug 05 2005 08:09 pm



Baconbutty wrote:


> A further idea I has was this.  If I call toString() on a function
> reference in the JScript engine, it will include all of the comments
> originally contained within the JS code, including  /*  */ comments.

> I could then access this using:-
> 
> myDataStore.toString()
> 
> and extract the test using RegExp or other like methods.
> 
> However, unlike the JScript engine, I have found that the Mozilla
> engine strips out comments in toString().

As far as I remember from previous discussions on this Mozilla's 
JavaScript engine compiles a function to byte code (which is not likely 
to store anything not executable like comments) and decompiles the byte 
code stored for a function when you call toString.

As for your idea, the ECMAScript edition 3 specification says on the 
toString method of Function objects: "An implementation-dependent 
representation of the function is returned. This representation has the
syntax of a FunctionDeclaration. Note in particular that the use and 
placement of white space, line
terminators, and semicolons within the representation string is 
implementation-dependent."

So you can try to use your approach if you want but you have to be aware 
that the result is implementation dependent and you can't complain if 
some implementation does not give you the same result as another 
implementation.

I think if you want to store and load data then you need to look at host 
specific ways to do that, e.g. in the browser by now you can use 
XMLHttpRequest in Mozilla, Opera 8, Safari 1.2, Konqueror 3.3, IE 5 and 
later to load XML data from a URL.


-- 

	Martin Honnen
	http://JavaScript.FAQTs.com/

.