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Re: Part 2: problems with 'pattern' spec

From: <zongaro@ca.ibm.com>
Date: Wed, 6 Feb 2002 15:23:58 -0500
To: www-xml-schema-comments@w3.org, rthompson@contivo.com
Message-ID: <OF6BBFDDFE.CDA33F88-ON85256B58.006CBF59@torolab.ibm.com>
Hi Ross,

     In [3], you wrote:

[[
I found two problems, I think, with the specification of the pattern
attribute. 

1) The type of the 'value' attribute of pattern is 'anySimpleType.' [1]
   Should it not be 'string'?

2) The definition of 'atom' in the BNF for regular expressions [2]
   says 

        atom ::= Char | charClass | ( '(' regExp ')' )

   'Char' says

        Char ::= [^.\?*+()|#x5B#x5D]

    Since '()' is included in 'Char', the status of these characters
    is, strictly speaking, ambiguous w.r.t. parsing an atom.

- Roß

[1] http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#element-pattern
[2] http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#nt-atom

]]

     Regarding your second point, the caret (^) at the beginning of the 
regular expression that defines "Char" indicates that that's a 
"negCharGroup", which means roughly "match anything except these 
characters."  So parentheses are actually excluded from Char, and I 
believe there's no ambiguity in parsing "atom".

     I'll leave it for someone else to respond to your first point.

Thanks,

Henry
------------------------------------------------------------------
Henry Zongaro      XML Parsers development
IBM SWS Toronto Lab   Tie Line 969-6044;  Phone (905) 413-6044
mailto:zongaro@ca.ibm.com
Received on Wednesday, 6 February 2002 15:24:22 UTC

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