Specifications for matching alternatives in a regexgroup?

[Michael Kay]

There is also a rule:
 
If two alternatives within the pattern both match at the same position in
the $input, then the match that is chosen is the one matched by the first
alternative. (Though the example is a bit different from this case).
 
Regards,

Michael Kay
http://www.saxonica.com/
http://twitter.com/michaelhkay 


  _____  

From: http://x-query.com/mailman/listinfo/talk [mailto:http://x-query.com/mailman/listinfo/talk] On Behalf
Of David
Sent: 07 May 2010 19:49
To: http://x-query.com/mailman/listinfo/talk
Subject: Re:  Specifications for matching alternatives in a
regexgroup?


Excellennt question !
The only rule I can find here
http://www.w3.org/TR/xpath-functions/#func-replace

Is 

"If two overlapping substrings of $input both match the $pattern, then only
the first one (that is, the one whose first character comes first in the
$input string) is replaced."

Which to my novice eyes would imply either is equally correct.



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

David A. Lee

http://x-query.com/mailman/listinfo/talk

http://www.calldei.com

http://www.xmlsh.org

On 5/7/2010 2:34 PM, David Sewell wrote: 

Given this query:



let $string := "This is an introduction to XQuery"

return (

  replace($string, '(introduction|intro)', 'XXX'),

  replace($string, '(intro|introduction)', 'XXX')

)



where both parts of the grouped expression are potential matches, is the

alternative to be matched defined by specification, or

implementation-dependent?



Trying in using three different XQuery parsers, two return



  "This is an XXX to XQuery",  "This is an XXXduction to XQuery"



(choosing the first alternative matched), while one returns



  "This is an XXX to XQuery",  "This is an XXX to XQuery"



(choosing the longest alternative matched).



  

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