XQuery - RegEx Pattern Matcher

[derstubbi at gmx.de]

Hi,
thanks for your answer, and even more thanks for your solution ;)

I have to admit that it took some minutes to understand your way, because I didnt even recognize that this could be a way.
The idea is quite simple (now, after I understand it), and seems to work for the most cases.
Thanks for your help !

P.S.:
It is quite interesting to see the differences between XSLT and XQuery. I should not insist on using only XQuery ;)



-------- Original-Nachricht --------
> Datum: Fri, 19 Jun 2009 08:44:31 -0400
> Von: "David A. Lee" <http://x-query.com/mailman/listinfo/talk>
> An: http://x-query.com/mailman/listinfo/talk
> CC: http://x-query.com/mailman/listinfo/talk
> Betreff: Re:  XQuery - RegEx Pattern Matcher

> 
> This may not be the best way to do it, but it works. and no regex.
> This wont trap "quoted quotes"  but it works on the example given and is 
> more readable then regexes to my caveman brain.
> 
> 
> --------------------
> declare variable $data := 
> 'foo;bar;"spam;bletch";another;"set;of;embedded";strings';
> 
> declare function local:nextstr( $s as xs:string ) as xs:string?
> {
>     if( starts-with($s , '"' ) ) then
>         concat( '"' , substring-before( substring( $s , 2 ) , '"' ) ,'"' )
>     else
>     let $sep := substring-before( $s , ";" )
>     return
>     if( $sep eq "" ) then $s else $sep
> };
> 
> declare function local:splitcsv( $s as xs:string ) as xs:string*
> {
>     if( string-length($s) eq 0 ) then
>         ()
>     else
>     let $first := local:nextstr( $s )
>     return
>     if( $first eq $s ) then
>         $s
>     else
>         ( $first , local:splitcsv( substring( $s , string-length($first) 
> + 2 ) ))
> 
> 
> };
> 
> for $s in local:splitcsv( $data )
> return <tag>{$s}</tag>
> -----------------------
> Returns
> 
> <tag>foo</tag>
> <tag>bar</tag>
> <tag>"spam;bletch"</tag>
> <tag>another</tag>
> <tag>"set;of;embedded"</tag>
> <tag>strings</tag>
> 
> 
> 
> 
> David A. Lee
> http://x-query.com/mailman/listinfo/talk  
> http://www.calldei.com
> http://www.xmlsh.org
> 812-482-5224
> 
> 
> 
> http://x-query.com/mailman/listinfo/talk wrote:
> >> In XQuery think I would start by doing a replace() to replace
> >> semicolons-not-within-quotes by some other delimiter (e.g. a PUA
> >> character),
> >> and then do a tokenize() to split the string on this new delimiter.
> >>     
> >
> > That is what I try to do ;)
> >
> > But, "...to replace semicolons-not-within-quotes..." needs Regex to find
> those, or not ?
> >
> >
> >
> >
> >   
> >>> -----Original Message-----
> >>> From: http://x-query.com/mailman/listinfo/talk [mailto:http://x-query.com/mailman/listinfo/talk] 
> >>> Sent: 19 June 2009 11:29
> >>> To: Michael Kay; http://x-query.com/mailman/listinfo/talk
> >>> Subject: Re: RE:  XQuery - RegEx Pattern Matcher
> >>>
> >>> I am trying to "read" CSV data like this :
> >>>
> >>> one;"two;stilltwo";three;"four;stillfour";five
> >>>
> >>> this should resolve in something like this :
> >>> ...
> >>> <element>one</element>
> >>> <element>two;stilltwo</element>
> >>> <element>three</element>
> >>> <element>four;stillfour</element>
> >>> <element>five</element>
> >>> ...
> >>>
> >>> if there is no separator(";") allowed within a text it is 
> >>> easy with just splitting a line with ";".
> >>>
> >>> But if there can be a ";" as a text, than I have to use RegEx.
> >>> I succeded in finding a XQuery-RegEx if in one line there is 
> >>> only one case where a ";" is used as text.
> >>>
> >>> But I need to find every match, so I used the \\G . Worked 
> >>> fine, so I hoped to reuse it in XQuery...
> >>>
> >>>
> >>>
> >>> -------- Original-Nachricht --------
> >>>       
> >>>> Datum: Fri, 19 Jun 2009 10:20:30 +0100
> >>>> Von: "Michael Kay" <http://x-query.com/mailman/listinfo/talk>
> >>>> An: http://x-query.com/mailman/listinfo/talk, http://x-query.com/mailman/listinfo/talk
> >>>> Betreff: RE:  XQuery - RegEx Pattern Matcher
> >>>>         
> >>>> The XPath regular expression language does not recognize \G and it 
> >>>> does not recognize non-capturing groups.
> >>>>
> >>>> As far as matches() is concerned, there is no distinction between 
> >>>> capturing and non-capturing groups, so replace "(?:" by "(".
> >>>>
> >>>> I suspect you wanted your regex to contain "\G". In Java 
> >>>>         
> >>> you need to 
> >>>       
> >>>> escape this as "\\G"; in XPath/XQuery, backslash is not a special 
> >>>> character and does not need to be escaped. However, there's 
> >>>>         
> >>> no "\G" in 
> >>>       
> >>>> XPath regular expressions anyway. In Java it means "the end of the 
> >>>> previous match"; but XQuery is a functional language, so 
> >>>>         
> >>> "previous" is 
> >>>       
> >>>> meaningless. At this stage I give up because I'm not sure 
> >>>>         
> >>> what you are 
> >>>       
> >>>> trying to do: you haven't supplied enough of your code.
> >>>>
> >>>> Regards,
> >>>>
> >>>> Michael Kay
> >>>> http://www.saxonica.com/
> >>>> http://twitter.com/michaelhkay
> >>>>
> >>>>         
> >>>>> -----Original Message-----
> >>>>> From: http://x-query.com/mailman/listinfo/talk
> >>>>> [mailto:http://x-query.com/mailman/listinfo/talk] On Behalf Of http://x-query.com/mailman/listinfo/talk
> >>>>> Sent: 19 June 2009 09:33
> >>>>> To: http://x-query.com/mailman/listinfo/talk
> >>>>> Subject:  XQuery - RegEx Pattern Matcher
> >>>>>
> >>>>> Hi,
> >>>>> I am trying to use a RegEx within XQuery. In general that 
> >>>>>           
> >>> works fine.
> >>>       
> >>>>> Now I have a more complex RegEx to work with CSV-files(these CSV 
> >>>>> have ";" as separator).
> >>>>> I use can the following without problems in Java :
> >>>>>
> >>>>> Pattern Regex = Pattern.compile(
> >>>>> "\\G(?:^|;)(?:\"((?:[^\"]|\"\")*)\"|([^\";]*))");
> >>>>> ...
> >>>>>
> >>>>> But in XQuery
> >>>>> let $regularExpr :='\\G(?:^|;)(?:\"((?:[^\"]|\"\")*)\"|([^\";]*))'
> >>>>> ...
> >>>>> if (matches($row,$regularExpr) ) then ( ...
> >>>>>
> >>>>> just gives the error :
> >>>>>
> >>>>> Error at character 4 in regular expression
> >>>>> "\\G(?:^|;)(?:\"((?:[^\"]|\"\")...": expected ())
> >>>>>
> >>>>>
> >>>>> I tried the optional flags (i, x, ...) but always with the same 
> >>>>> result...
> >>>>> What is wrong with this RegEx ?
> >>>>>
> >>>>> P.S. :I run the XQuery from Java with Saxon.
> >>>>>
> >>>>>
> >>>>> --
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> >>>>> _______________________________________________
> >>>>> http://x-query.com/mailman/listinfo/talk
> >>>>> http://x-query.com/mailman/listinfo/talk
> >>>>>           
> >>>> _______________________________________________
> >>>> http://x-query.com/mailman/listinfo/talk
> >>>> http://x-query.com/mailman/listinfo/talk
> >>>>         
> >>> --
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> >>>       
> >> _______________________________________________
> >> http://x-query.com/mailman/listinfo/talk
> >> http://x-query.com/mailman/listinfo/talk
> >>     
> >
> >   

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