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

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Amelia A. Lewis wrote:
> On Sat, 1 Nov 2003 23:16:03 -0500
> "Alessandro Triglia" <sandro@mclink.it> wrote:
>>Rich Salz ha scritto:
>>>I think you misunderstand Simon.  Does ASN.1/X.694 have the 
>>>equivalent of a "text node"?  For example:
>>>	<foo>this is <item>1<item> line of text with
>>>        <item>2</item> numbers in it.</foo>
>>>What about
>>>	<foo>A second line with <item>1<item>, <item>2</item>, no,
>>>        <item>3</item> numbers.</foo>
>>>In XML Schema, those match the same definition of foo.  How 
>>>do you write the equivalent in ASN.1/X.694?
> Please note the question.  The answer doesn't address it.
>>ASN.1 supports mixed content in the "Extended XML encoding rules"
>>You can write a type definition such as the following:
>>MyElementTypeWithMixedContent ::= [EMBED-VALUES] SEQUENCE {
>>	embed-values SEQUENCE OF UTF8String,
>>	an-attribute [ATTRIBUTE] INTEGER,
>>	another-attribute [ATTRIBUTE] UTF8String,
>>	a-child-element AnotherElementType,
>>	another-child-element INTEGER
>>[EMBED-VALUES] and [ATTRIBUTE] are examples of "XER encoding
>>The [EMBED-VALUES] encoding instruction assigned to the SEQUENCE type
>>causes the multiple strings of the "embed-values" component (the first
>>component of the SEQUENCE) to provide the text that is interleaved
>>with the child elements (before the first one, between each pair, and
>>after the last one). In this example, there are two (mandatory) child
>>elements ("a-child-element" and "another-child-element"), so there
>>must be exactly three strings(possibly empty) in the SEQUENCE OF
> But that isn't mixed content.  Not in the XML sense.  If I *must* write
> <p>String <b>emphasized</b> the end.</p>  But I *want* to write
> <p>String <b>some <i>real nonsense</i>, no?</b> Or perhaps
> <b>not</b>.</p>
> Classic document-style mixed content.  Very useful stuff if, for
> instance, you're embedding documentation into a product description. 
> The example provided, if I understand it correctly, cannot support that.

Alessandro was just demonstrating mixed content - allowing arbitrary 
nesting of <i> and <b> is easy, just you define your 'text' type to be 
allowed to containg BoldText and ItalicText types - but BoldText and 
ItalicText are just aliases for Text, meaning they can be nested inside 
each other (or themselves!).

> ASN.1 as a non-mixed-content schema language for XML that has the
> ability to generate [unparsable, disastrously fragile*] compact binary
> structures has interesting use cases. 

Don't confuse "having the ability to generate [unparsable, disastrously 
fragile] compact binary structures" with "only being able to generate ...";

 > An inability to support mixed
> content means it isn't a replacement for DTDs, WXS, or RNG, all of which
> do have that capability.

Good job ASN.1 doesn't have such an inability, then, isn't it?

> Amy!



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