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   Re: [xml-dev] ASN.1 is an XML Schema Language (Fix those lists!)and Bina

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Michael Champion wrote:

> Trouble is, you can't make sense of an ASN.1 message without having the 
> schema, and I mean the EXACT schema, used to generate it. 

That depends what encoding you use!

PER (packed encoding) doesn't make any sense without the schema, just 
like you say.

BER (basic encoding, the most popular) makes some sense: The data is 
annotated with field boundaries and types, so a tool can split it into a 
tree and show strings as strings and integers as integers and so on, but 
without variable names.

XER (XML encoding) makes some sense: The data is annotated with field 
boundaries and names, so a tool can split it into a tree and show 
everything as strings, but without knowledge of types.

 > That's (oops,
> smell of impending flames <grin>) the value proposition for XML in a 
> nutshell, IMHO, and why it is used in all those projects Simon mentioned 
> where ASN.1 is, on paper, better suited.

I doubt many people who use XML for a project really consider the 
alternatives. When asked, the average XML user tends to list the reason 
for using XML as:

"I can share information with other programs, with any structure I want"

...because much of the XML hype has been "WOW! Now it's possible to 
COMMUNICATE BETWEEN BITS OF SOFTWARE using the Internet rather than just 

Many Internet developers came straight into Web development, and have 
never really seen the 'big picture'. Until XML came along, their code 
talked to:

1) Backend server apps written by remote, distant, clever people: SQL 
servers, DNS servers, LDAP servers, etc. The thought of writing one's 
own "server" and "protocol" was unthinkable.

2) Users, via HTML in their browser, which was easy.

XML's biggest contribution to the Web has been to get these developers 
thinking about how easy it is to set up communications between 
components, rather than really making it easier, IMHO ;-)



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