Groups > comp.lang.java.programmer > #11862

Re: Interplatform (interprocess, interlanguage) communication

From	BGB <cr88192@hotmail.com>
Newsgroups	comp.lang.java.programmer
Subject	Re: Interplatform (interprocess, interlanguage) communication
Date	2012-02-08 18:49 -0700
Organization	albasani.net
Message-ID	<jgv8og$6ac$1@news.albasani.net> (permalink)
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On 2/8/2012 3:02 PM, Lew wrote:
> BGB wrote:
>> ...
>> an example is this:
>> <foo>  <bar value="3"/>  </foo>
>> and:
>> (foo (bar 3))
>>
>> now, consider one wants to add a new field to 'foo' (say 'ln').
>> <foo ln="15">  <bar value="3"/>  </foo>
>> and:
>> (foo 15 (bar 3))
>>
>> a difference here is that existing code will probably not even notice
>> the new XML attribute, whereas the positional nature of most
>
> Ahem. You mean other than failing schema validation?
>

many of us don't use schemas with our XML.

I think the issue is that one particular technology, XML, is used in 
significantly different ways by different people and for different reasons.

many people use XML for data-binding, and many other people who use it 
could care less about data-binding.

some people may use XML for similar purposes to how people using Lisp 
would use lists (never-mind if this is kind of awkward, it does work).

like, doing Lisp type stuff in Java using DOM-nodes in place of 
cons-based lists... +1 now that Java also (sort of) has closures.

>> S-Expressions makes the latter far more likely to break something (and
>
> More likely than failing schema validation was for that well-designed XML-based
> application?
>

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.

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?

http://en.wikipedia.org/wiki/Abstract_syntax_tree

>> there is no good way to "annotate" an S-Exp, whereas with XML it is
>> fairly solidly defined that one can simply add new attributes).
>
> Attributes in XML are not annotation (with or without quotes). That role is  filled by the actual 'annotation' element
> http://www.w3schools.com/schema/el_annotation.asp
>

they can be used for annotating the nodes in many sane use cases...

a lot depends on how one is using the XML in a given context.

>> note: my main way of working with XML is typically via DOM-style
>> interfaces (if I am using it, it is typically because I am directly
>> working with the data structure, and not as the result of some dumb-ass
>> "data binding" crud...).
>
> Sorry, "dumb-ass 'data-binding' crud"?
>
> Why the extreme pejoratives? I would not say that there's anything wrong with
> XML data-binding /per se/, although as with documented-oriented approaches it
> can be done very badly.
>

yeah, this may have been stated overly strongly.

personally, IMO, data-binding is probably one of the worse and 
technically more pointless ways of using XML (as, IMO, it leads to such 
similarly ill-designed technologies as SOAP and similar...).

not that data-binding is itself necessarily itself pointless, but doing 
it via overly verbose namespace-ridden XML is probably one of the worse 
ways of doing it (vs either specialized file-formats, or the use of 
binary data-binding formats, which IMO should also not be used for data 
interchange).

admittedly, I also partly dislike traditional ways of using data-binding 
as it often exposes things which are theoretically internal to the app, 
namely structural data representation (via classes/...), with things 
which should theoretically be isolated from the internal data 
representation: file formats.

or, IOW: a file-format (or protocol/...) should express the data in 
itself, and not express how it is physically represented within the 
application.

likewise, data going into or coming out of a piece of code should be 
ideally documented and defined in a form separate from the component in 
question.

otherwise, data-binding is not that much different than a more modern 
variant of writing raw structures and arrays to files.

>> typically, the "internal representation" and "concrete serialization"
>> are different:
>
> I don't understand what you mean here. You cite these terms in quotes as though
> they are a standard terminology for some specific things, but use them in their
> ordinary meaning. The internal representation of what? The serialization
> ("concrete" or otherwise) of what? I don't mean to be obtuse here, but I am not
> grokking the referents.
>

the internal representation of the data within the application code.

if one knows which objects or classes exist, what sorts of members they 
contain, ... then one is essentially exposing data which should not be 
visible, or for that matter relied upon for data interchange (or, for 
that matter, relevant).

ideally, any data represented externally should be defined in terms of 
its semantics: something will be present if it is relevant to the 
meaning of the data. the serialization will then be defined in terms of 
expressing the structure and semantics of the data, which may bear very 
little resemblance to how the data is represented in the actual 
classes/arrays/whatever which make up how the data is represented 
internally to the application.

similarly, file formats should be as much abstracted from the 
application code as is reasonably possible, with a "concrete" 
specification for the file-format or data-representation being written 
instead.

both XML and S-Expressions can be used as structured ways of 
representing semantics, rather than as ways of representing the contents 
of given a data-object.

>> I may use a textual XML serialization, or just as easily, I could use a
>> binary format;
>> likewise for S-Exps (actually, I probably far more often represent
>> S-Exps as a binary format of one form or another than I use them in a
>> form externally serialized as text).
>>
>> all hail the mighty DOM-node or CONS-cell...
>
> WTF?
>

DOM nodes can be very powerful (and are probably a much better way of 
using XML than using it as some sort of data-binding thing).

cons-cells are pairs of dynamically-typed values, typically called "car" 
and "cdr" and used to implement lists and similar (and are the main 
building block of "everything" in languages like Lisp and Scheme, well, 
along with "symbols" and "fixnums" and similar).

http://en.wikipedia.org/wiki/Cons_cell

they can also be implemented in C, C++, and Java without too much 
trouble, and can be a fairly useful way of building various sorts of 
data structures (although, sadly, they aren't nearly as efficient in 
Java as they could be, but OTOH it is also sort of a pain to build a 
dynamic type-system in C, so it probably evens out...).

then one can proceed to build logic based mostly on building and 
processing lists.

or, conceptually, they can be regarded as a type of linked-list based 
containers, however the ways they are traditionally used are 
significantly different from traditional ways of using containers (they 
are typically used as ways of building tree-structures, rather than 
usually as ways of storing a collection of items).

it may be worthwhile to look-up information regarding Lisp and Scheme 
and similar, not that there is necessarily much reason to actually use 
the languages, but there are some ideas and ways of doing things which 
can be mapped fairly nicely onto other, more common, languages.

Thread

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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