6 Replies Latest reply: Nov 4, 2011 1:50 PM by Marc Autret RSS

    Regular Expressions in CS5.5 - something is wrong

    inspiria_si

      Hello Everybody,

       

      Please correct me, but I think, I found a serious problem with regular Expressions in Indesign CS5.5 (and possibly in other apps from CS5.5).

       

      Let's start with simple example:

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

      var range = "a-a,a,a-a,a";

      var regEx = /(a+-a+|a+)(,(a+-a+|a+))*/;

      alert( "Match:" +regEx.test(range)+"\nLeftContext: "+RegExp.leftContext+"\nRightContext: "+RegExp.rightContext );

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

      What I expected was true match and the left  and the right context should be empty. In Indesign CS3 that is correct BUT NOT in CS5.5.

       

      In CS 5.5 it seems that the only first "a-a" is matched and the rest is return as the rightContext - looks like big change (if not parsing error in RegExp engine).

       

      Please correct me if I am wrong.

       

      The second example - how to freeze ID CS5.5:

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

      var range = "a-a,a,a-a,a";

      var regEx = /(a+-a+|a+)(,(a+-a+|a+)){8,}/;

      alert( "Match:" +regEx.test(range)+"\nLeftContext: "+RegExp.leftContext+"\nRightContext: "+RegExp.rightContext );

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

      As you can see it differs only with the {8,} part instead of *

      Run it in CS5.5 and you will see that the ID hangs (in CS3 of course it runs flawlessly}.

       

      The third example - how to freeze ID 5.5 in one line (I posted it earlier in Photoshop forum because similiar problem was called earlier):

       

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

      alert((/(n|s)? /gmi).test('s') );

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

      As you can guess - it freezes the CS5.5 (CS3 passes the test).

       

       

      Please correct me if I am doing something wrong or it's the problem of Adobe.

       

      Best regards,

      Daniel Brylak

        • 1. Re: Regular Expressions in CS5.5 - something is wrong
          inspiria_si Community Member

          In reference to my previous message: After some digging, I think that the main problem is that regExp in CS5.5 works in non-greedy mode (despite the fact that the documentation says opposite)

           

          I don't know any way to change it back to greedy mode.

           

          After all it does not explain the possibility of freezing when executing some expressions.

           

          I would be grateful if someone had any idea what am I doing wrong or maybe someone has workaround for that?

           

          b.r.

          Daniel

          • 2. Re: Regular Expressions in CS5.5 - something is wrong
            Marc Autret MeganK

            Hi Daniel,

             

            Thanks for sharing. Really annoying indeed.

            Just to complete your diagnosis, what you describe about CS.5 is the same in CS5, while CS4 behaves as CS3.

             

             

            var range = "aaaaa";
            var regEx = /(a+-a+|a+)(,(a+-a+|a+))*/;
            
            alert([
                "Match:" +regEx.test(range),
                "LeftContext: "+RegExp.leftContext.toSource(),        // => CS3/4: EMPTY -- CS5+: EMPTY
                "RightContext: "+RegExp.rightContext.toSource()        // => CS3/4: EMPTY -- CS5+: ",a,a-a,a"
                ].join('\r'));
            

             

            So there is a serious implementation problem of the RegExp object from ExtendScript CS5.

             

            I don't think it's related to the greedy modes. By default, JS RegExp quantifiers are greedy, and /a*/ still entirely captures "aaaaaa" in CS5+.

            By the way, you can make any quantifier non-greedy by adding ? after the quantifier, e.g.: /a*?/, /a+?/, etc.

             

            I guess that Adobe ExtendScript has a generic issue in updating the RegExp.lastIndex property in certain contexts—see http://forums.adobe.com/message/3719879#3719879 —which could explain several bugs such as the Negative Class bug —see http://forums.adobe.com/message/3510078#3510078 — or the problems you are mentioning today.

             

            @+

            Marc

            • 3. Re: Regular Expressions in CS5.5 - something is wrong
              inspiria_si Community Member

              Hi Marc,

               

              Thans for the complement of diagnosis. I recently upgraded from CS3 to CS5.5 and was not able to check the behaviour in CS4 and CS5.

               

              Getting to the point, you are right that it's not the greedy mode problem - I've checked some other simple examples and sometimes worked as expeced, and sometimes suddenly wrong (freezing the execution).

               

              Well then, I reported the bug to Adobe(and I suspect, I was not the first one)  - we will see what happens.

               

              Best regards,

              Daniel

              • 4. Re: Regular Expressions in CS5.5 - something is wrong
                seuzo Community Member

                I cannot be sure in whether it relates to this problem.

                Please perform this sample code.

                var str = "2011-11-03";
                //var str = "11-03";
                //var str = "03";
                var regex = /^((\d+)-)?((\d+)-)?(\d+)$/;
                
                $.writeln("Match : " + regex.test(str));
                $.writeln("RegExp.$1 : " + RegExp.$1);
                $.writeln("RegExp.$2 : " + RegExp.$2);
                $.writeln("RegExp.$3 : " + RegExp.$3 );
                $.writeln("RegExp.$4 : " + RegExp.$4 );
                $.writeln("RegExp.$5 : " + RegExp.$5 );
                

                I get:

                Match : true
                RegExp.$1 : 2011-
                RegExp.$2 : 2011
                RegExp.$3 : 11-
                RegExp.$4 : 11
                RegExp.$5 : 03
                

                It's right!

                But, If str = "11-03" then

                Match : true
                RegExp.$1 : 11-
                RegExp.$2 : 11
                RegExp.$3 : 
                RegExp.$4 : 03
                RegExp.$5 : 03
                

                RegExp.$4 captured "03" why?

                and, If str = "03" then

                Match : true
                RegExp.$1 : 
                RegExp.$2 : 03
                RegExp.$3 : 
                RegExp.$4 : 03
                RegExp.$5 : 03
                

                RegExp.$2 captured "03"

                 

                I reported to Adobe site.

                • 5. Re: Regular Expressions in CS5.5 - something is wrong
                  inspiria_si Community Member

                  Hi Seuzo,

                   

                  I confirm the same results both in CS5.5 and CS3 (the versions I can check) - It leads to conclusion that CS3 implementation of RegExp was wrong too.

                   

                  I believe that this is the same problem - just the guys from Adobe made a mess with the implementation

                   

                  b.r

                  Daniel

                  • 6. Re: Regular Expressions in CS5.5 - something is wrong
                    Marc Autret MeganK

                    Daniel, Seuzo,

                     

                    Just posted a basic ScriptUI dialog to make regex-testing easier:

                    http://www.indiscripts.com/post/2011/11/extendscript-regexp-tester

                     

                    @+

                    Marc