Right now, without having done anything yet with X:S:Machines, the problem that I envision is the issue of synch vs asynch operation. My understanding is that with Machines, say you chain 100 filters on it with one generator object. When I send any SAX event from the generator object, that event has to be handled by each filter in order, assuming that those filters process and resend the event upstream. But now that I type this out (don't you just hate that? :-), I realize that one can have filters that get sax events but don't do anything until certain conditions are met. This would be necessarily in a case where one might have a Machine that worked line-by-line on a file, but diverged at some point to two different processing paths, and then remerged back to a single path. At some point, at the merge, you need to make sure that you don't send the data upstream until you get a matching set of elements from the divergant point. Again, here's where XML comes in handy, because these bits of XML that 'flow' around would contain history of where they came from and where they're going.

I was thinking about FBP earlier this week and saw the Machines article on perl.com, so I'm considering trying it this weekend to see if something reasonable can be done.

-----------------------------------------------------
Dr. Michael K. Neylon - mneylon-pm@masemware.com || "You've left the lens cap of your mind on again, Pinky" - The Brain
"I can see my house from here!"
It's not what you know, but knowing how to find it if you don't know that's important

public class ProcXML extends Network {

    
    protected void define() throws Throwable {
        connect(component("Read", ReadText.class),
            port("OUT"),
            component("XMLToObj", XMLToObj.class),
            port("IN"));

        connect(component("XMLToObj"),
            port("OUT"),
            component("Discard", Discard.class),
            port("IN"));        
        
           initialize(new FileReader("c:\\com\\jpmorrsn\\eb2engine\\te
+st\\data\\myXML3.txt"),
            component("Read"),
            port("SOURCE")); 

        
        }


    public static void main(String[] argv) {
        new ProcXML().go();
        }
}
[download]

It names 3 components, and links them together using named ports. It is actually not too dissimilar from the SAX machine syntax, but your network can be as complex as you like.

XMLToObj is an XML parser I wrote that runs in the JFBP environment.

Your comment in the second para seems to suggest that you can use such a specification to link components written in different languages - I didn't know you could do that in Java. Where would I look to find out?

I don't know how you would do it in Java. But if your components live in different processes that communicate through IPC, there is no reason that you can't implement each component in a different language.

In Perl you can lift the requirement of separate processes through liberal use of the Inline module.

I don't understand what a SAX event is. To me, an event is something happening at a point in time - in FBP, it's usually the arrival of a data chunk (IP) at a network node, but it could be an external event, like completion of I/O. Also, sending anything upstream is un-FBP-like!

Last comment: most of the SAX:Machine functions have counterparts in FBP, but in a more general way. I don't see a need for special functions like Manifold....