XML Schema Standard 1.0 - W3C - Regular Expressions - Patterns

Dear XML Schema WG members,



I’m currently working on XML schemas to be used for a financial  
application.

There is a specific requirement aiming to provide a data type where:

1)      all strings must be length at least 1 and at most 35;

2)      the sequence “//” is not allowed within the first 16  
characters of each string;

3)      the sequence “//” is allowed within the substring [17..35] of  
each string.

The general idea was to use regular expressions as defined in:

XML Schema Part 2: Datatypes

W3C Recommendation 02 May 2001

F Regular Expressions

and then, to find a suitable “regular expression” to define a proper  
“pattern”, more or less

as in the following:

<xs:simpleType name="First16TextCheck">

<xs:restriction base="xs:string">

<xs:pattern value="????"/>

</xs:restriction>

</xs:simpleType>

However, after several attempts, seems not so simple to define a  
suitable

“regular expression” that matches all the above features (1), (2) and  
(3).

The presence (or absence) of "//" seems to remain a problem when  
using regular

expressions and patterns (mainly because … in my understanding … the  
NOT operator

applies only to single characters and the "-" operator applies to  
group of characters and not

to sets of strings).



Could you kindly provide me any hint about the above issue?



Thank you in advance for your cooperation.



Kind Regards

------------------------------------------------------------------------ 
-

Giovanni Carchesio
Banca d'Italia
Largo Guido Carli 1 - 00044 Frascati (Rome) - Italy
ICT Department
Institutional Applications Development Division
Telephone: +39 06 4792 6689
Fax:          +39 06 4792 6641
E-mail:      giovanni.carchesio@bancaditalia.it
URL:         www.bancaditalia.it




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