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Re: C.4 Undeclared entities?



On Mon, 28 Oct 1996 11:13:57 -0800 (PST), Bill Smith <bill.smith@eng.sun.com>
wrote:

>Stipulating that only valid XML documents may be interchanged is heavy handed 
>and will limit acceptance. This requirement could preclude a variety of 
>applications since it would effectively prevent the interchange of 
>works-in-progress. Rather than exchanging documents in their "current state", 
>some intermediate, "valid state" would have to be artifically created. We could 
>specifiy mechanisms for going from invalid to valid and back again, or we could 
>just let documents be exchanged.
>
>This level of formalism isn't needed.
>

If we took your point literally, Bill, it would require an XML processor to
accept any character string and make sense of it. There has to be some
definition of "input that an XML processor is expected to handle".

Tim has made the distinction between "valid", meaning "conforming to an explicit
DTD", and "well-formed", meaning "processable without reference to an explicit
DTD". An interchanged XML document has to be one or the other, not just an
arbitrary string.

For "valid" documents, there would be a DOCTYPE declaration with an explicit
external and/or internal subset. Such a document would clearly conform to SGML
as well.

As Eliot has pointed out, merely "well-formed" XML documents could announce
themselves and also be SGML conforming if they were introduced by the following
declaration:

<!DOCTYPE doctypename SYSTEM>

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Charles F. Goldfarb * Information Management Consulting * +1(408)867-5553
           13075 Paramount Drive * Saratoga CA 95070 * USA
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