[sc34wg3] TMCL issue: regex?

[Lars Marius Garshol]

* Patrick Durusau
>
> Well, I made the connection because we just went through this in ODF  
> and realized you were mis-quoting the XML Schema Appendix, which  
> reads: [...]

Hmmmm. Actually, the draft isn't quoting XML Schema at all. The draft  
says what it means for a string (s) to match a regular expression (r).

It needs to say this because throughout the draft there are statements  
like this one:

> For each instance i of t the set of its subject identifiers which  
> match r is referred to as S.


To understand what this means, you need to see the definition in 3.8,  
which says that a subject identifier (s) matches (r) if (s) "is a  
member of the set of strings L(r) denoted by r as defined in [XML  
Schema-2]." In other words, XML Schema is what defines the matching.

> "A ·regular expression· <http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/#dt-regex 
> > /R/ is a sequence of characters that denote a *set of strings*  /L 
> (R)/."

Yep. So L(R) is the set of all strings which match (R). Therefore, if  
our string (s) is a member of L(R) it matches (R). So the text works  
just fine.

> Defining what it means to match a regular expression isn't the same  
> thing as defining a regular expression language.

True, but XML Schema does both.

> If TMCL processor must/should support XML Schema Part 2, Appendix F,  
> then let's simply say that.

Clause 11 says you are conformant if you can "validate topic maps  
against valid TMCL schemas as defined in Clause 4", and there's no way  
to do that without supporting XML Schema Part 2, Appendix F, because  
that's where the regexp syntax we use is defined, and clause 3.8 says  
that it's defined there.

We could say it again in clause 11, but personally I feel that would  
be redundant.

If this is the key point (whether to say in clause 11 that  
implementations must support that regexp language) I can add an issue.

--Lars M.
http://www.garshol.priv.no/tmphoto/
http://www.garshol.priv.no/blog/