Subj : Re: [SpiderMonkey] Serializing JSObject
To   : netscape.public.mozilla.jseng
From : ggadwa@charter.net
Date : Wed Jun 23 2004 05:42 pm

Brendan Eich wrote:

>> Question two:  Why does JSTYPE's have JSTYPE_NUMBER, but in reality 
>> it's either a DOUBLE or an INT (easy enough to figure out.)  Nothing 
>> else drills down like that.  Just wondering.
>
>
> This API corresponds to the typeof operator in the language, which 
> does not distinguish between double and int (that distinction is an 
> implementation detail, from the language user and spec points of view).
>
> Since you are dealing with an implementation of the language here, 
> namely SpiderMonkey, you might rather use JSVAL_IS_INT, 
> JSVAL_IS_DOUBLE, etc., than JS_TypeOfValue.

Ah ... okey dokey.  I use JS_TypeOfValue to filter out the things I 
don't want to serialize (i.e., functions, and currently, objects, though 
that will change.)  I use the _IS_ to filter it down further.  That 
makes sense to me.

>
>> I'll post up the code (in case it's useful to anybody, it would be 
>> quite easy to modify it to save objects and recurse through them.)  
>> Might be something useful for core.
>
>
> Generally, serialization is domain-specific.

If you did it a compact way, it would be.  I'm basically generating 
strings that are ... to a point ... human readable.  I never serialize 
into bytes (which would blow away different machines) - but serialize 
into strings.  Length bytes are all text, etc.  This should be crossable 
to all domains.  It'd be an interesting way to pass off objects between 
load-balanced servers (not that anybody would do that!)

For instance, if you had a object that had three properties, and int, a 
double, a boolean, and a string, it could look like:

I        myIntProperty               67
D       myDoubleProperty        1.345+E00
B       myBooleanProperty       T
S       myStringProperty           10         My String!

When I add objects, they will just be tabbed in after the start of the 
'O' object definition.  So be pretty portable.

>
> Did you look at the XDR stuff? 

Yeah, but everything seems to be more complex then it needs to be :)  
Surely, there's good reason, but what I think is useful is just two 
function calls that take a JSObject, return a string, and the opposite.  
Nothing else to be done.

[>] Brian

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