[Bug 1909] RQ21: BNF, regex, etc for special types (anySimpleType, anyAtomicType)

http://www.w3.org/Bugs/Public/show_bug.cgi?id=1909


cmsmcq@w3.org changed:

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------- Additional Comments From cmsmcq@w3.org  2006-01-04 13:21 -------
A draft wording proposal was sent to the Working Group 15 Dec 2005
for consideration.  It makes explicit that the lexical mapping
relation for the special types is not a function.  The relevant part
of the proposal for anySimpleType reads as follows; similar text
is provided for anyAtomicType.


3.2.1.1 Value space

The .value space. of anySimpleType is the union of the .value
spaces. of all the .primitive. datatypes defined here, and of all
sets of lists formed from the members of the
.primitive. datatypes.

At least in theory, the .value space. of anySimpleType also
includes all values of anything that might in future be added to
the set of .primitive. datatypes, as well as lists including
those values. That is, users of the datatypes defined here should
not assume that the .value space. of anySimpleType is limited to
values in the .primitive. datatypes defined in this version of
this specification. They might be values from other datatypes not
defined here.


3.2.1.2 Lexical mapping

The .lexical space. of anySimpleType is the set of all
finite-length sequences of characters (as defined in [XML]) that
.match. the Char production from [XML]. This is equivalent to the
union of the .lexical spaces. of all .primitive. datatypes.

The .lexical mapping. of anySimpleType is the union of the
.lexical mappings. of all .primitive. datatypes and all list
datatypes. It will be noted that this mapping is not a function:
a given literal may map to one value or to several values of
different .primitive. datatypes, and it may be indeterminate
which value is to be preferred in a particular context. When the
datatypes defined here are used in the context of [XML Schema
Part 1: Structures], the xsi:type attribute defined by that
specification in section xsi:type can be used to indicate which
value a literal which is the content of an element should map
to. In other contexts, other rules (such as type coercion rules)
may be employed to determine which value is to be used.


3.2.1.3 Facets

When a new datatype is defined by .facet-based restriction.,
anySimpleType must not be used as the .base type.. So no
.constraining facets. are directly applicable to anySimpleType.

Received on Wednesday, 4 January 2006 13:21:09 UTC