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Re: why (Q re well-formedness constraints)

From: C. M. Sperberg-McQueen <cmsmcq@uic.edu>
Date: Mon, 04 May 1998 18:34:26 +0200
Message-Id: <3.0.32.19980504183425.006c5638@nora.hit.uib.no>
To: "Richard L. Goerwitz III" <richard@goon.stg.brown.edu>, xml-editor@w3.org
At 15:00 01.05.98 -0400, Richard L. Goerwitz III wrote:
>Why is the following condition added to paragraph 3.1 of the XML
>spec?
>
>===
>
>Well-Formedness Constraint: No External Entity References 
>  Attribute values cannot contain direct or indirect entity references
>  to external entities.

I'll answer the question you ask, not the implicit ones.  It's there
because the normalization of attribute values and presentation of the
normalized values to downstream applications needs to be cheap and
fast, and a large majority of the WG felt and feels that expansion of
references to external entities is not cheap and is often not fast.

Like a number of constraints relating to entity structure and declaration,
this one is complicated by the fact that non-validating processors are
not required to read the external portions of the DTD.  This complication
has two consequences:  first, yours is not a dumb question.  Second,
I will need to check the wording carefully to see whether your
implicit questions point to a problem that needs fixing.

Thanks for the comments; keep 'em coming.

-C. M. Sperberg-McQueen
 University of Illinois at Chicago
Received on Monday, 4 May 1998 12:28:00 GMT

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