> URL: http://www.w3.org/TR/2005/WD-xpath-functions-20050211/#ERRFORX0002
                                 ^^^
Note that is an early working draft, not the final version.

You want

http://www.w3.org/TR/xpath-functions/#regex-syntax

XSD/XPath regex are not the same as perl's.

> I want to separate the string at each white-space if the string before 
> is longer than 70 signs


why not
substring(.,1,70),tokenize(substring(.,71),'\s+')

David

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