ASN.1 is an XML Schema Language (Fix those lists!) and Binary XML not needed...

["Bob Wyman" <bob@wyman.us>]

Title: Message

A call for fairness and equal rights...

Now that X.694 has been approved, ASN.1 based systems can generate and consume just about any XML object that can be defined using XML Schema. Thus, there seems to be no reason why ASN.1 wouldn't be considered to be just as much an "XML Schema Language" as any of the other more well-known languages like XML Schema, Relax NG, Schematron, etc. Yet, of hundreds of sites and many books that include lists and/or discussions of languages for describing XML schemas,  virtually none mention ASN.1... This doesn't make sense to me. It seems to me that responsible writers would include references to ASN.1 as an XML schema language. If ASN.1 was limited in its ability to describe XML objects, I could understand its exclusion from discussion, however, such limitations no longer exist.

 

ASN.1 based systems are able to generate not only XML in the full complexity that can be described by XML Schema, but they will also typically be capable of generating binary, compressed formats like PER, BER, DER, etc. This combined with the ability to encode XER, CXER and E-XER and the appearance of XML Schema to ASN.1 translators means that developers have the option of using either or both text-based XML or compact and efficient binary encodings with *a single programming interface!*. This flexibility hasn't been available to the XML community before and essentially makes mute and unnecessary the whole discussion of "Binary XML." (i.e. don't bother with binary XML. If you need something like a "binary XML," then just use ASN.1 as your XML schema language.  By switching encoding modules at runtime, you can switch back and forth between XML and something like PER on a connection-by-connection basis with little or no code impact.) (I know this works. I do it.)

 

Given that ASN.1 is now capable of fully describing XML objects, it should be included in all lists of "XML schema languages." And, we should put to bed the now mute discussion of "Binary XML." XML should stay in the realm it started in -- a text-based language for tagged data exchange. The problem of binary exchange is handled well by others...

 

        bob wyman