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ISP problem [was Union types derived by restriction ]

From: Bryan Rasmussen <brs@itst.dk>
Date: Mon, 20 Sep 2004 13:14:29 +0200
Message-ID: <2292448FDD501C4594181CA35CBA172003B821C0@its42.itst.local>
To: xmlschema-dev@w3.org



-----Oprindelig meddelelse-----
Fra: Michael Kay [mailto:mhk@mhk.me.uk]
Sendt: 20. september 2004 12:03
Til: Bryan Rasmussen
Emne: RE: Union types derived by restriction 


Yes, I'm sorry about this. My ISP did this to me one day last week, the
problem appeared to be solved, and now it's happening again. I'm listening
to the musak fromm their support desk as I write. In the interests of
sanity, I am not sending this message to the list - perhaps you could
forward it.

Michael Kay

> -----Original Message-----
> From: Bryan Rasmussen [mailto:brs@itst.dk] 
> Sent: 20 September 2004 10:48
> To: 'Michael Kay'
> Cc: xmlschema-dev@w3.org
> Subject: SV: Union types derived by restriction 
> 
> I don't know if somethings up with your mailer, mine or the 
> list, but I've
> now received 10+ copies of this mail. I guess we'll see with 
> this if it's
> the list. 
> 
> -----Oprindelig meddelelse-----
> Fra: Michael Kay [mailto:mhk@mhk.me.uk]
> Sendt: 20. september 2004 11:40
> Til: xmlschema-dev@w3.org
> Emne: Union types derived by restriction 
> 
> 
> 
> In Schema Part 1 (PER 18 Mar 2004), section 3.14.6, Schema Component
> Constraint: Derivation Valid (Restriction, Simple), is the rule:
> 
> 3.3.2.3 The {member type definitions}, in order, must be 
> validly derived
> from the corresponding type definitions in the {base type 
> definition}'s
> {member type definitions} given the empty set, as defined in ...
> 
> However, I'm having trouble seeing how one can define a union as a
> restriction of another union in which the member type 
> definitions differ in
> any way from those of the base type definition. 
> <xs:restriction> only allows
> me to change the pattern and enumeration facets, not the member types.
> 
> For example:
> 
> (a) if the base type is a union of decimal and string, can I make the
> derived type be a union of integer and string? Unless I'm 
> missing something,
> I think not.
> 
> (b) if the base type is a union of dateTime, date, and time, 
> can I make the
> derived type be a union of dateTime and date? Again, I think not.
> 
> So what does rule 3.3.2.3 mean? My suspicion is that it is vacuous.
> 
> Michael Kay
> 
> 
> 
> 
> 
Received on Monday, 20 September 2004 11:15:10 UTC

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