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I wrote:
>
>
> Bob Wyman wrote:
> >
> > I argue that if something is
> > marked to be an attribute when converted to XML, then it
> > should be marked as an attribute when it is passed through an
> > interface like SAX which is commonly used to process XML-like
> > data. If this were not the case, then binary data would look
> > different to the user of SAX when it was read directly via
> > SAX rather than being read from a chunk of XML written by the
> > XML encoder. This would be silly and unproductive.
>
>
> I absolutely agree. Another way of saying this is that the
> stream of SAX
> callbacks coming from parsing/decoding an encoding of ASN.1 (BER, PER,
> EXTENDED-XER) has to be exactly the same stream, for a given
> schema and a
> given instance, regardless of the encoding rules in use (BER, PER,
> EXTENDED-XER), and has to be the same stream as would be
> generated by a
> "normal" SAX parser parsing the XML document. It must be possible to
> replace a normal SAX parser used by an application with an ASN.1
> parser/decoder for either XML or binary encodings with
> minimum changes to
> the application code. This will give us the interoperability we need
> between the two worlds.
And it is not just about attributes vs. elements. It is also about:
- mixed content,
- variable-order sequences (those consisting in a group of elements whose
order in the instance "doesn't matter" (*)),
- removing wrappers around multiple occurrences of things,
- CHOICEs corresponding to XSD's type derivation hierarchies,
- CHOICEs corresponding to XSD's element substitution groups,
- CHOICEs corresponding to XSD's unions,
- "SEQUENCE OF"s corresponding to XSD's lists,
- support of wildcards,
and so on.
All these features (and others) are supported by an XER-specific notation in
the ASN.1 schema, which affects EXTENDED-XER encodings but does not affect
BER/PER encodings. However, a SAX XMLReader over BER/PER should behave *as
if* BER/PER encodings contained some representation of the above things as
EXTENDED-XER does.
Alessandro Triglia
(*) or "matters", depending on people's views and use cases (ASN.1 supports
both views/use cases).
>
> Alessandro Triglia
>
>
>
>
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