- From: Michael Anderson <michael@research.canon.com.au>
- Date: Tue, 30 Jan 2001 18:06:49 +1100
- To: "Henry S. Thompson" <ht@cogsci.ed.ac.uk>
- Cc: francis@redrice.com, Adalbert Wysocki <waldi@imediation.com>, xmlschema-dev@w3.org
"Henry S. Thompson" wrote: > <snip> > > There is no difference between absent and empty. The infoset for that > element has no children. So following clauses [1] [2] will apply, > _provided_ the element has a simple type definition, e.g. you need to > modify your example slightly to > > <xs:element name="weather" type="xs:token" fixed="wet"/> > > If the declaration has a {value constraint}, then provided clause > 1.2.2 has not obtained . . . > 3.2 > If the {value constraint} is fixed, the element information item > must have no element information item [children], and the > normalized value must be either empty or match the string of the > {value constraint}; > > If an element information item is valid with respect to an element > declaration as per Element Locally Valid (Element) (§3.3) and the > {value constraint} is present, but clause 1.2.2 of Element Locally > Valid (Element) (§3.3) above does not obtain and the element > information item has no element or character information item > [children], the post-schema-validation infoset has the {value > constraint}'s string as the item's [schema normalized value] > property and its [specified] is set to schema. Otherwise, the > item's [specified] is set to instance. > > ht > > [1] http://www.w3.org/TR/xmlschema-1/#cvc-elt > [2] http://www.w3.org/TR/xmlschema-1/#sic-eltDefault sigh, one day i'll get my terminology correct. I realize there is no difference between absence, empty content and empty. But is there a difference between absence and an _empty_string_? In this thread is appears that <weather></weather> represents absence, but in another post [ http://lists.w3.org/Archives/Public/xmlschema-dev/2001Jan/0145.html ], it implies <weather></weather> has actual content, ie is _not_ absent, and the child character information item is an empty string. So if I change the example to: <xs:element name="weather" type="condition" default="wet"/> <xs:simpleType name = "condition"> <xs:restriction base="xs:string"> <xs:enumeration value = "wet"/> <xs:enumeration value = ""/> <xs:enumeration value = "dry"/> </xs:restriction> </xs:simpleType> And the instance is <weather></weather>. What is the value of the weather? is is "wet" or ""? thanks for your patience, mick.
Received on Tuesday, 30 January 2001 02:07:04 UTC