george.profenza

I have noticed that max's javascript interpreter has E4X support. The problem is it seems to be limited. I don't know if the limitation comes the size of the js file or it's something else. I'm completely lost.

Here is a basic path to illustrate the idea:

contents of globals.js used in the patcher:

inlets = 1;
outlets = 0;
autowatch = 1;

var g = new Global("g_xml");
g.xml = 

    
    
    


    
    
    


    
    
    


    
    
    


    
    
    


        
        
         


        
        
        


    
    
    


    


    
    
    


    
    
    


    
    
    


    
    


    
    
    
    
    
        
        
    

        
        
        
    
    
        
        



function bang(){
    post(g.xml.toString());
}

function create() {}

A friend is trying to use xml for it's tree structure to play some videos non-linearly. Here is an example of a basic function that also uses E4X:

function get_video(){
    var path = xml.section.(@name == arguments[0]).video.(@key ==
arguments[1]).@path.toString();
    section = xml.section.(@name == arguments[0]).video.(@key ==
arguments[1]).@section.toString();
    //post('your next section is ' + section);
    outlet(0,"path",path);
    outlet(0,"section",section);
}

arguments[0] is a string, the name of a section and arguments[1] is a key.

The HUGE problem is once I bang that globals.js object, Max crashes. That happens all the time, tested on 2 different machines. If I leave just half of the section nodes in, Max doesn't crash.

Does anyone have an idea why that happens and what can I do go around the issue ?

max-crashes-when-using-js-and-xml

I think the problem is in your XML. Starting with "checkpoint_7a" you are using a different formatting.

I think the problem is in your XML.  Starting with "checkpoint_7a" you are using a different formatting.

I wished you were right, it would've been so simple.

I formatted the js file using TextMate, no luck.

The crash is pretty consistent.
If I use this much nodes:

If I add another node, like so:
'
xml = 
'
Max crashes :(


Try reformatting "checkpoint_5a" to conform to the pattern in the previous entries:

I did try that, and even removed all returns and tabs...just wrote the xml as one long line:

That behaves exactly like the before, crashing :(

Max uses the SpiderMonkey javascript engine (by Mozilla). Try checking their lists and docs for bugs related to XML.

I had a quick look at the SpiderMonkey, but I find it hard to track down if indeed my problem is a listed bug:

https://bugzilla.mozilla.org/buglist.cgi?bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&component=Javascript+Engine

This would be a major bug in SpiderMonkey though. Not sure if SpiderMonkey is used under the hood by actionscript, but the same code works well/doesn't crash flash player.

Maybe there's a problem with the text editor in Max and E4X.

I had a quick look at the SpiderMonkey, but I find it hard to track down if indeed my problem is a listed bug:
https://bugzilla.mozilla.org/buglist.cgi?bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&component=Javascript+Engine
I've looked for 'limit' and 'E4X'

https://cycling74.com/docs/max5/vignettes/js/jsintro.html)

https://developer.mozilla.org/en/New_in_JavaScript_1.6

I guess that the pre 1.6 versions of SpiderMonkey contained an experimental implementation of E4X, and what you encountered is actually a bug in that version that was later fixed for the 1.6 release.

A workaround could be to use the Rhino interpreter instead, through an mxj object.

Hm. According to the docs (https://cycling74.com/docs/max5/vignettes/js/jsintro.html) Max supports version 1.5 of JavaScript. 

But E4X was added in 1.6, right?
https://developer.mozilla.org/en/New_in_JavaScript_1.6

A workaround could be to use the Rhino interpreter instead, through an mxj object.
http://www.mozilla.org/rhino/


Btw, Flash Player use Tamarin, not SpiderMonkey.

i'm curious... what happens if you construct the XML object by doing 

i'm curious... what happens if you construct the XML object by doing new XML('the xml as as string') instead?


@Hans You are perfectly right. There is not support for Javascript 1.6 yet and the code worked here and there because of the experimental E4X implementation.

I will follow the documentation and try to see how I get along with Rhino :)

Let me also recommend against using XML - it's a sucky format for data interchange for numerous reasons.

If you have the choice, strongly consider using JSON. It's far easier to read in Javascript (you can just paste it into your code, it's valid Javascript) and doesn't have the "two sorts of containment" issue that makes XML such a drag.

If you have the choice, strongly consider using JSON.  It's far easier to read in Javascript (you can just paste it into your code, it's valid Javascript) and doesn't have the "two sorts of containment" issue that makes XML such a drag.


Max Crashes when using js and xml