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Re: Interplatform (interprocess, interlanguage) communication

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BGB wrote:
> Lew wrote:
> > Arne Vajhøj wrote:
> >> BGB wrote:
> >>> as noted, many people neither use schemas nor any sort of schema
> >>> validation. in many use-cases, schemas are overly constraining to the
> >>> ability of using XML to represent free-form data, or using them
> >>> otherwise would offer little particular advantage.
> >>
> >> xsd:any do provide some flexibility in schemas.
> >>
> >>> say, if one is using XML for compiler ASTs or similar (say, the XML is
> >>> used to represent a just-parsed glob of source-code), do they really
> >>> need any sort of schema?
> >>
> >> I would expect syntax trees to follow certain rules and not be free
> >> form.
> >
> > In one breath we're singing the praises of binary formats, in the next we
> > complain that XML isn't sufficiently flexible.
> >
> 
> it is not like one can't have both:

XML is much easier to modify and maintain when flexibility is a requirement.

> have a format which is at the same time is a compressed binary format, 
> and can also retain the full flexibility of representing free-form XML 
> semantics, ideally without a major drop in compactness (this happens 
> with WBXML, and IIRC should also happen with EXI about as soon as one 
> starts encoding nodes which lie outside the schema).
> 
> this is partly why I was advocating a sort of pattern-building adaptive 
> format: it can build the functional analogue of a schema as it encodes 

That rather defeats the purpose of having a schema.

A schema is a contract that the various processes or other stakeholders use to 
guarantee correctness of the XML and guide processing. If you develop it /ad 
hoc/ you lose that contract.

> the data, and likewise does not depend on a schema to properly decode 
> the document. it is mostly a matter of having the format predict when it 
> doesn't need to specify tag and attribute names (it is otherwise similar 
> to a traditional data-compressor).

I'm sure that's very clever, but it defeats the purpose of XML schema.

> this is functionally similar to the sliding-window as used in deflate 
> and LZMA (7zip) and similar (in contrast to codebook-based data 
> compressors). functionally, it would have a little more in common with 
> LZW+MTF than with LZ77 though.

... and now you're off on some weird tangential topic.

> granted, potentially a binary format could incorporate both support for 
> schemas and the use of adaptive compression.
> 
> 
> is XML really the text, or is it actually the structure?

Huh?

> I had operated under the premise that it was the data-structure (tags, 
> attributes, namespaces, ...), which allows for pretty much anything 
> which can faithfully encode the structure (without imposing too many 
> arbitrary restrictions).

Huh?

XML is a formal specification for structured documents that is devoid of 
semantics.

> > "Do they really need any sort of schema?" with XML is usually a "yes".
> >
> > But only if you're interested in clear, unambiguous, readily-parsable and
> > maintainable XML document formats.
> >
> 
> fair enough, I have mostly been using it "internally", and as noted, for 
> some of my file-formats, I had used a custom binary coded variant 
> (roughly similar to WBXML, but generally more compact and supporting 
> more features, such as namespaces and similar, which I had called SBXE). 
> it didn't make use of schemas, and worked by simply encoding the tag 
> structure into the file, and using basic contextual modeling strategies.

Bully.  Good on ye.

> it also compared favorably with XML+GZ in my tests (which IIRC was also 
> generally smaller than WBXML). remotely possible would also be XML+BZip2 
> or XML+LZMA.

Compared "favorably" according to what criteria?

> I had considered the possibility of a more "advanced" format (with more 
> advanced predictive modeling), but didn't bother (couldn't see much 
> point at the time of trying to shave off more bytes at the time, as it 
> was already working fairly well).

Huh?

> > People often excoriate the supposed verbosity of XML as though it were the only
> > criterion to measure utility.
> >
> 
> well, a lot depends...
> 
> for disk files, really, who cares?...
> for a link where a several kB message might only take maybe 250-500ms 
> and is at typical "user-interaction" speeds (say, part of a generic "web 
> app"), likewise, who cares?...
> 
> 
> it may matter a little more in a 3D interactive world where everything 
> going on in the visible scene has to get through at a 10Hz or 24Hz 
> clock-tick, and if the connection bogs down the user will be rather 
> annoyed (as their game world has essentially stalled).

And that's a use case for XML how, exactly?

Saying "XML is bad because it doesn't keep bananas ripe" would be equally 
relevant.

> one may have to make due with about 16-24kB/s (or maybe less) to better 
> ensure a good user experience (little is to say that the user has a 
> perfect internet connection either).
> 
> so, some sort of compression may be needed in this case.
> (yes, XML+GZ would probably be sufficient).

Back in the universe where we're discussing XML's suitability, please.

> if it were dial-up, probably no one would even consider using XML for 
> the network protocol in a 3D game.

Oh, you're talking about inter-node communication in a distributed game. Thanks 
for finally making that clear. XML would be just fine as a transmission protocol for such a thing. I'm not saying ideal, but just fine.

If you're talking about network protocols you certainly are not talking about 
frame-by-frame transmission of data with reply at 10 Hz, no matter what the 
protocol, so your entire argument against XML for such a thing is moot.

> > There is no inherent advantage of a LISP/list-like format over any other, nor vice versa; it's all accordin'. If the convention is agreeable to all parties,
> > it will work. If all projects were one-off and isolated from the larger world,
> > we'd never need to adhere to a standard. If we don't mind inventing our own
> > tools for anything, we'd never have to adopt a standard with extensive tools
> > support.
> >
> 
> it is possible, it all depends.
> 
> a swaying factor in my last choice was the effort tradeoff of writing 
> the code (because working with DOM is kind of a pain...). IIRC, I may 

Huh? again. There's very little effort in writing XML code, whether DOM, JAXB, 
SAX or StAX, given the wide availability of libraries to do so.

> have also been worrying about performance (mostly passing around lots of 
> numeric data as ASCII strings, ...).

Based on what measurements?

> but, I may eventually need to throw together a basic encoding scheme for 
> this case (a binary encoder for list-based data), that or just reuse an 
> existing data serializer of mine (mostly intended for generic data 
> serialization, which supports lists). it lacks any sort of prediction or 
> context modeling though, and is used in my stuff mostly as a container 
> format for bytecode for my VM and similar.
> 
> 
> > Where are the *real* costs of a software system?
> >
> 
> who knows?...

Anyone who thinks about it realistically.

> probably delivering the best reasonable user experience?...

That's not a cost, that's a goal.

> for a game:
> reasonably good graphics;
> reasonably good performance (ideally, consistently over 30fps);
> hopefully good gameplay, plot, story, ...
> 
> well, that and "getting everything done" (this is the hard one).

Those aren't costs. Those are goals.

Clear conclusions require clear reasoning on actual facts with relevance.

-- 
Lew

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Re: Interplatform (interprocess, interlanguage) communication jebblue <n@n.nnn> - 2012-02-07 12:11 -0600
  Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-07 16:38 -0700
    Re: Interplatform (interprocess, interlanguage) communication Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-07 20:26 -0400
      Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-08 01:41 -0700
        Re: Interplatform (interprocess, interlanguage) communication Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-08 07:19 -0400
          Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-08 12:07 -0700
            Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-08 21:16 -0500
              Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-08 19:50 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-09 06:24 -0400
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-09 09:15 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-09 18:58 -0400
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-09 16:15 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-09 18:50 -0500
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-09 21:40 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-11 14:47 -0500
                Re: Interplatform (interprocess, interlanguage) communication Lew <lewbloch@gmail.com> - 2012-02-11 12:06 -0800
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-11 15:18 -0500
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-11 23:03 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-12 09:27 -0500
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-12 13:33 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-12 15:50 -0500
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-12 14:34 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-09 18:48 -0500
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-09 21:46 -0700
                Re: Interplatform (interprocess, interlanguage) communication Lew <lewbloch@gmail.com> - 2012-02-10 08:51 -0800
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-10 10:43 -0700
                Re: Interplatform (interprocess, interlanguage) communication Lew <lewbloch@gmail.com> - 2012-02-10 13:15 -0800
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-10 14:50 -0700
                Re: Interplatform (interprocess, interlanguage) communication Lew <lewbloch@gmail.com> - 2012-02-10 14:32 -0800
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-10 17:10 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-10 22:08 -0400
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-11 00:49 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2012-02-11 14:04 -0400
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-11 14:55 -0500
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-11 14:52 -0500
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-11 20:06 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-11 22:41 -0500
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-12 00:46 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-12 09:29 -0500
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-12 09:31 -0500
                Re: Interplatform (interprocess, interlanguage) communication Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-12 16:02 +0000
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-12 11:16 -0500
                Re: Interplatform (interprocess, interlanguage) communication Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-12 22:46 +0000
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-12 11:33 -0700
                Re: Interplatform (interprocess, interlanguage) communication Lew <lewbloch@gmail.com> - 2012-02-11 20:18 -0800
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-12 01:36 -0700
                Re: Interplatform (interprocess, interlanguage) communication Joshua Cranmer <Pidgeot18@verizon.invalid> - 2012-02-12 13:52 -0600
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-12 14:43 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-11 14:49 -0500
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-09 18:46 -0500
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-09 18:45 -0500
        Re: Interplatform (interprocess, interlanguage) communication Lew <lewbloch@gmail.com> - 2012-02-08 14:02 -0800
          Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-08 18:49 -0700
            Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-08 21:14 -0500
              Re: Interplatform (interprocess, interlanguage) communication Lew <lewbloch@gmail.com> - 2012-02-08 20:07 -0800
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-08 23:29 -0700
                Re: Interplatform (interprocess, interlanguage) communication Lew <lewbloch@gmail.com> - 2012-02-09 09:40 -0800
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-09 17:02 -0700
              Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-08 21:10 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-09 18:54 -0500
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-10 10:25 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-11 14:45 -0500
                Re: Interplatform (interprocess, interlanguage) communication Lew <lewbloch@gmail.com> - 2012-02-11 12:14 -0800
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-11 15:20 -0500
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-11 22:20 -0700
                Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-12 09:23 -0500
                Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-12 12:13 -0700
    Re: Interplatform (interprocess, interlanguage) communication Arne Vajhøj <arne@vajhoej.dk> - 2012-02-07 20:24 -0500
    Re: Interplatform (interprocess, interlanguage) communication Martin Gregorie <martin@address-in-sig.invalid> - 2012-02-08 01:31 +0000
      Re: Interplatform (interprocess, interlanguage) communication BGB <cr88192@hotmail.com> - 2012-02-08 00:55 -0700

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