- From: Joseph Reagle <reagle@w3.org>
- Date: Thu, 29 Nov 2001 13:56:42 -0500
- To: Jeni Tennison <jeni@jenitennison.com>
- Cc: xmlschema-dev@w3.org, henry@w3.org, xenc <xml-encryption@w3.org>
On Thursday 29 November 2001 06:03, Jeni Tennison wrote: > When you extend a type, the start of the content model of the new type > has to be exactly the same as the start of the base type. That means > you can't change the type of an element from the base type when you > derive by extension. Hi Jenni, Thank you for your thoughtful email, your solutions describe what I thought (feared) was the order of magnitude necessary to meet the requirement. We are trying to use schema in two ways. First, to provide a complete/precise definition that a schema validator can use to check instance syntax. Second, to communicate via excerpts in the specification the data structure and processing required of implementations. We can get "complex" with multiple derived types which is fine for the machine, but doesn't really help readers of the spec: creating a whole intermediary type just to restrict-then-expand, or create a type just to remove the nonce would make the spec more confusing... Consequently, I'm thinking Takeshi's solution might be the least awkward of the options available to us, "I agree with you that it is not so easy to remove the Nonce attribute from the CipherData element. So how about containing the attribute not in the [CipherData] element but in the EncryptedData element, though it may be a little weird..." -- Joseph Reagle Jr. http://www.w3.org/People/Reagle/ W3C Policy Analyst mailto:reagle@w3.org IETF/W3C XML-Signature Co-Chair http://www.w3.org/Signature/ W3C XML Encryption Chair http://www.w3.org/Encryption/2001/
Received on Thursday, 29 November 2001 13:56:54 UTC