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From: Eddie Robertsson [mailto:firstname.lastname@example.org]
Sent: Sun 6/23/2002 6:28 PM
To: Dare Obasanjo
Cc: John Cowan; Rick Taylor; email@example.com
Subject: Re: [xml-dev] XML Schema to relaxNG xslt
>The above looks perfectly valid at
>a first glance but when you pick up the magnifier glass you will find
>that the base type has a required attribute "firstSubscribed" which is
>made optional in the derived type. This is not a valid restriction
>because you can never remove anything that is required in the base type.
>I'm not sure if this was a simple typo by Dare or if he wasn't aware
>that this was indeed an illegal derivation.
It was a typo/mixup. The schema violated the "child validates a subset of what the parent can validate" informal rule that I use for remembering how to derivation by restriction works. I should have attempted to validate it instead of composing it inline. :)
>XML Spy4.4 and MSXML4 both (incorrectly) says the above type derivation is valid
Thanks for the heads up, I'll file a bug about this.