tag:blogger.com,1999:blog-6800934446457898793.post8345470441664339492..comments2010-07-04T08:49:32.897-04:00Jeff Moserhttp://www.blogger.com/profile/16074905903060665396noreply@blogger.comBlogger24125tag:blogger.com,1999:blog-6800934446457898793.post-39355245653246557512010-03-23T21:27:35.996-04:002010-03-23T21:27:35.996-04:00<b>Anonymous</b>: It seems like the Koders link work again.<br /><br /><b>Lisa</b>: You can use regular expressions to create test data. In fact, Visual Studio Team System Database Edition <a href="http://msdn.microsoft.com/en-us/library/aa833197.aspx" rel="nofollow">does this</a>. One approach is to take the regex tree and then try every unicode character that will work in the character accept function and keep iterating. Alternatively, just pick any random character that would work at each step. The min and max length would come out of the first approach (but max length could be infinite)Jeff Moserhttp://www.blogger.com/profile/16074905903060665396noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-68517854036010167062009-12-29T09:07:16.908-05:002009-12-29T09:07:16.908-05:00Thanks for the great insights! Once a Regex is analyzed, could it be used to create testdata? Following problem: Have an XMLSchema with patterns (=Regex) and would like to create data entry forms. Would be great to at least find out minlength and maxlength. The Regex used for XMLSchema does not support backtracking and capture but still can be quite complex. Gratefull for any suggestions...Lisanoreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-79999658236309755132009-10-19T17:09:40.170-04:002009-10-19T17:09:40.170-04:00This looks like it is a great post. I wish that the koders.com links were still active. Thanks for your effort.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-25144162754406687372009-09-25T05:59:36.078-04:002009-09-25T05:59:36.078-04:00I&#39;m sorry to lower the tone, but I couldn&#39;t resist noting that the featured o&#39;reilly book cover looks like two owls shagging.<br /><br />Here ends my intellectual contribution to this article.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-71093098377160525432009-08-01T12:21:37.959-04:002009-08-01T12:21:37.959-04:00Great article, I learned a lot. Thanks for mentioning <a href="http://ultrapico.com/Expresso.htm" rel="nofollow">Expresso</a>.Jim Hollenhorsthttp://ultrapico.comnoreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-56485163943881740662009-05-31T14:13:20.727-04:002009-05-31T14:13:20.727-04:00RBarryYoung: Glad you liked it! I hope it was helpful.<br /><br />I had fun using an obscure Regex feature (matching balanced group) in <A HREF="http://stackoverflow.com/questions/928563/code-golf-evaluating-mathematical-expressions/930319#930319" REL="nofollow">my answer to a recent code golf competition on Stack Overflow</A>.Jeff Moserhttp://www.blogger.com/profile/16074905903060665396noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-8114987498392031322009-05-25T12:57:27.833-04:002009-05-25T12:57:27.833-04:00Awesome explanation!RBarryYounghttp://www.blogger.com/profile/14923866352814870307noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-11553006577240900602009-04-14T09:21:00.000-04:002009-04-14T09:21:00.000-04:00Tareq_sust: Thanks! Hopefully it helped out.<br /><br />Jeffrey Friedl: Wow! I'm humbled by a celebrity appearance :) Loved your book. You're right, it took a lot longer to write up than the few nights of stepping through the source code. I can only imagine the many hours over several years it took to write your book.<br /><br />Thanks for stopping by!Jeff Moserhttp://www.blogger.com/profile/16074905903060665396noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-27712896061310943352009-04-14T07:31:00.000-04:002009-04-14T07:31:00.000-04:00Wow, incredible writeup! I bet composing it took longer than learning what went into composing it :-)Jeffrey Friedlhttp://regex.info/blog/noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-92125911642172314672009-03-24T03:00:00.000-04:002009-03-24T03:00:00.000-04:00this is one of the best article i have ever read on regular Expression. Warm wishes for your success ..Tareq_sustnoreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-3064894462811305182009-03-18T09:31:00.000-04:002009-03-18T09:31:00.000-04:00Donald: Thanks!<BR/><BR/>Terry: I use The Regulator as well. It's pretty good, but for some reason it tends to want to crash on startup and I have to keep deleting the config file to fix it, that's why I've used other tools.Jeff Moserhttp://www.blogger.com/profile/16074905903060665396noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-390931047310089122009-03-17T18:26:00.000-04:002009-03-17T18:26:00.000-04:00Good post! I would also like to recommend this tool: <BR/>http://sourceforge.net/projects/regulator/<BR/><BR/>Regulator gives instant feedback on the goofy regex's that you're trying to fix or understand.Terrynoreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-34588372059914881782009-03-17T08:21:00.000-04:002009-03-17T08:21:00.000-04:00great article Jeff. Should take a couple of days to fully comprehend this. Keep up the good work :)Donaldhttp://www.blogger.com/profile/15965825275076072672noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-13584242567359973382009-03-17T08:14:00.000-04:002009-03-17T08:14:00.000-04:00Arthur: I agree. Jeff Atwood <A HREF="http://www.codinghorror.com/blog/archives/000633.html" REL="nofollow">brought this up</A> two years ago and got a response from the Program Manager responsible for this part of Visual Studio (Neil Enns). He said:<BR/><BR/>"It is a very oddball regex syntax, and as best we can tell it comes from Visual C++ 2.0. We did want to add additional support for .NET 2.0-style regular expressions in the Visual Studio 2005 release, but unfortunately due to time pressures it didn't make the final list of features."<BR/><BR/>and <BR/><BR/>"We do keep this on our list of things we want to fix. Ideally at some point we'll actually build in a nifty little extensibility point so you can wire up any regex engine you want for searches."<BR/><BR/>So, hopefully one day it'll be fixed :)Jeff Moserhttp://www.blogger.com/profile/16074905903060665396noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-84317963101250529982009-03-16T23:08:00.000-04:002009-03-16T23:08:00.000-04:00Great article, thanks a lot.<BR/><BR/>My pet hate as a .net developer is that Visual Studio doesn't support regular expressions. I mean it's got it's own weird dialect, but at the very least it should support ECMA Script regexes. I end up using third party tools to do things that should be a trivial part of the IDE.Arthurnoreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-48295479921214143982009-03-16T20:56:00.000-04:002009-03-16T20:56:00.000-04:00Shafi, Murat Ozgur Kaymakci, Judah Himango, AmrElGarhy, Christopher Weeks: Thanks for the kind words!<BR/><BR/>Anonymous: My brief experience with <A HREF="http://www.regexbuddy.com/" REL="nofollow">RegexBuddy</A> was positive. I like its debug window which shows backtracking. <BR/><BR/>For simple regex creation, I like <A HREF="http://www.ultrapico.com/Expresso.htm" REL="nofollow">Expresso</A>.<BR/><BR/>Jacob: Oops. Egg on my face :) You're absolutely right. Great catch! <BR/><BR/>My table and explanation were incomplete. I didn't mention the intermediate skip. I updated the table and description.<BR/><BR/>Thanks again for catching this. I owe you one!Jeff Moserhttp://www.blogger.com/profile/16074905903060665396noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-54352802614936193952009-03-16T20:10:00.000-04:002009-03-16T20:10:00.000-04:00Sorry about not being specific about the confusion. I'm referring to the analysis beginning at "In need of an interpreter".<BR/><BR/>It seems like the Boyer-Moore optimization would check at character indexes { 6, 13 } and find a candidate and start backtracking. But maybe I need to read more about that algorithm.Jacobhttp://jacobcarpenter.wordpress.com/noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-2371138215805035362009-03-16T20:04:00.000-04:002009-03-16T20:04:00.000-04:00I'm a little confused as to why the 2nd letter checked isn't the second "t" in http (character index 13).Jacobhttp://jacobcarpenter.wordpress.com/noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-56723756683017662172009-03-16T17:22:00.000-04:002009-03-16T17:22:00.000-04:00Wow! I'm one of the programmers who are good enough to make a living at it but bumps around the really hard stuff. I'm glad you and the others do this kind of research and then write it up. That's awesome.Christopher Weekshttp://www.blogger.com/profile/07640683757330420292noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-88262647731508991812009-03-16T15:45:00.000-04:002009-03-16T15:45:00.000-04:00Check out RegExBuddy sometime.. it helped me learn regular expressions at warp speed.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-46841799242677378722009-03-16T15:08:00.000-04:002009-03-16T15:08:00.000-04:00Great effort and nice article, keep it upAmrElGarhyhttp://www.igurr.comnoreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-37093961613270035102009-03-16T14:51:00.000-04:002009-03-16T14:51:00.000-04:00Great article!Judah Himangohttp://www.blogger.com/profile/10277699587853707632noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-38034834210005482912009-03-16T11:59:00.000-04:002009-03-16T11:59:00.000-04:00very very good article. thanks.Murat Ozgur Kaymakcihttp://www.blogger.com/profile/10618219481434116143noreply@blogger.comtag:blogger.com,1999:blog-6800934446457898793.post-30294604540741314202009-03-16T10:00:00.000-04:002009-03-16T10:00:00.000-04:00CoolShafinoreply@blogger.com