regex-coach September 2005

regex-coach@common-lisp.net

5 participants
7 discussions

RE: [regex-coach] Greetings and a puzzle
by Allen, Greg 27 Sep '05

27 Sep '05

I think the problem is poorly specified: what does "two words" really mean? Essentially which of these are two words? abc1def2 ab_def12 _abcd12_ twowords12 All match against Edi's rather neat regex, but are they valid? Is "_" part of a word or a word separator? :) -----Original Message----- From: regex-coach-bounces(a)common-lisp.net [mailto:regex-coach-bounces@common-lisp.net] On Behalf Of Edi Weitz Sent: Tuesday, September 27, 2005 2:13 PM To: Frank Cc: regex-coach(a)common-lisp.net Subject: Re: [regex-coach] Greetings and a puzzle Hi! On Tue, 27 Sep 2005 08:27:26 -0400, Frank <lists(a)frankmarion.com> wrote: > Hi, I'm new to the list. I was looking for a nice regex list, and > found this one. This is not a general regex list, it is specifically for the "Regex Coach" application. > A programmer wants to test a password, and he wants to do it in ONE > expression. Here are the criteria for a well formed password > > 1) Minumum of eight characters in length > 2) Two words [a-z_] are required > 3) Two digits [0-9] are required. (?=.*[a-z_].*[a-z_])(?=.*[0-9].*[0-9]).{8,} Cheers, Edi. _______________________________________________ regex-coach site list regex-coach(a)common-lisp.net http://common-lisp.net/mailman/listinfo/regex-coach ------------------------------------------------------------------------------ This message is intended only for the personal and confidential use of the designated recipient(s) named above. If you are not the intended recipient of this message you are hereby notified that any review, dissemination, distribution or copying of this message is strictly prohibited. This communication is for information purposes only and should not be regarded as an offer to sell or as a solicitation of an offer to buy any financial product, an official confirmation of any transaction, or as an official statement of Lehman Brothers. Email transmission cannot be guaranteed to be secure or error-free. Therefore, we do not represent that this information is complete or accurate and it should not be relied upon as such. All information is subject to change without notice.

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[regex-coach] Greetings and a puzzle
by Frank 27 Sep '05

27 Sep '05

Hi, I'm new to the list. I was looking for a nice regex list, and found this one. Let me start off with an interesting puzzle that someone sent me A programmer wants to test a password, and he wants to do it in ONE expression. Here are the criteria for a well formed password 1) Minumum of eight characters in length 2) Two words [a-z_] are required 3) Two digits [0-9] are required. I've been working on this all night, and what I've come up with is the following An alpha and a numeric will always be side to side. This will catch it [a-z_][0-9]|[0-9][a-z_] <group alpha fb number OR number fb alpha> The problem is that there might be a run of non-matches before, or following, or between each of these pairs. One might be inclined to say "Ah! Then the solution is to add {2,}. Not so, because then it would return the match of a1a1 but not a1xa1. It would catch a1 then 1x (it's the closest match). This is the crux of the problem, as I've been able to figure so far. It's a tough but interesting puzzle. I'd be interested in hearing your options. Frank Marion lists(a)frankmarion.com Keep the signal high.

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[regex-coach] Re: RegEx coach and selecting from the top view
by Edi Weitz 20 Sep '05

20 Sep '05

[Please use the mailing list for bug reports and other things.] Hi! On Mon, 19 Sep 2005 11:40:13 +0000, Björn Róbertsson <bjornr(a)simi.is> wrote: > When I select a part of or the whole regular expression the CPU load > goes up to 100 % and habitually the best way is to do End Task. > > The machine runs Windows XP, firewall, antivirus et. al. > > I am including a screenshot of one particular regexp which exhibits > this behaviour. > > This is a cpu graph, the tops (100%) occur when: the window is > brought into focus while the regexp is highlighted, also when the > regexp is highlighted (i.e. from back to front), when it’s changed, > when the window is moved and so on. > > I do not believe my regular expression to be very complicated but > something is not right. Your regular expression (that I include here for reference) ^\S+.*\S+.*\S+.*\d+\:\d+\:\d+ \d+ ([\.0-9]+\.1\.13\.10) Normal.*\" ([\.0-9]+) -.* ([\.0-9]+) is formed in a way that leads to an exponential growth in backtracking - the behaviour that you see is what I would expect. Note that in particular each ".*" forces the engine to go to the end of the target string and from there retry each position backwards. These attempts will be nested. Try the stepper to see what I mean. You should rewrite the regex to avoid this. Cheers, Edi.

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[regex-coach] Re: Regex Coach
by Edi Weitz 18 Sep '05

18 Sep '05

On Fri, 16 Sep 2005 22:21:33 +0200 (CEST), Maciej Żenczykowski <maze(a)cela.pl> wrote: > Pentium III 1 GHz + 512MB ram (Linux - Fedora Core 3) > > The Regex: > > # some 200 chars of comments > (?: - (?: 0 | [1-9]\d{0,3} | [12]\d{4} | 3[01]\d{3} > | 32[0-6]\d\d | 327[0-5]\d | 3276[0-8] ) > | (?:\+|(?<![\d+\-])) (?: 0 | [1-9]\d{0,3} | [12]\d{4} | 3[01]\d{3} > | 32[0-6]\d\d | 327[0-5]\d | 3276[0-7] ) )(?!\d) > # should match -32768 to -0, and [+]0 to [+]32767 > > with 'x' and 'g' options > > target string: > > 1 2 3 -5 -130 -128 -127 -111 -99 -9 -1 0 +0 -0 +1 123 +99 +130 > 345+34+11 0x10e -32768 -32769 -9 -99 -999 -9999 -99999 -29999 -39999 > -31999 -32999 -32799 -32699 -32769 -32759 -32768 -0 0 +0 99999 39999 > 32999 32799 32769 32768 32767 32759 32699 31999 29999 9999 999 99 9 0 > > requires roughly 2 seconds for a screen update. Hmm, screen update on my laptop (Pentium M 2.0 GHz, XP pro) is without a noticable delay - even if I run the app from within VMWare (simulating Debian Linux with 512 MB of RAM). Should it be that my CPU is so much faster than yours? Cheers, Edi.

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[regex-coach] Re: Regex Coach
by Edi Weitz 17 Sep '05

17 Sep '05

On Fri, 16 Sep 2005 23:20:13 +0200 (CEST), Maciej Żenczykowski <maze(a)cela.pl> wrote: > I did, but it seems to bounce - requires me to register. Yes, you'll have to register. > It seems I was to quick in reporting no bugs - the step'er does not > honor the 'x' or 'g' flags of the regex. Yes, you're right that the stepper (and other parts of the system as well) has problems with the 'x' flag - I wasn't aware of that. I'll try to fix this ASAP. The 'g' flag doesn't make sense in the stepper, though. It is only meaningful for replacement operations - see the documentation. Thanks, Edi.

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[regex-coach] Re: Regex Coach
by Edi Weitz 16 Sep '05

16 Sep '05

[Please use the mailing list for questions, bug reports, or feature requests - see Cc.] Hi! On Thu, 15 Sep 2005 22:25:47 +0200 (CEST), Maciej Żenczykowski <maze(a)cela.pl> wrote: > Beautiful program Thanks! > however I'd like to ask for two features: > > 1) the ability to turn off parsing after every change of the regex (I > think it recompiles and retests everything), as this makes changes > slow once the regex is large (ie allow manual updating, or delayed > updating or something, or background updating) > > even a simple checkmark for autoupdate (default on) would be enough Can you send me the regex that caused these problems? What hardware do you have? Yes, the app has to re-compile and re-check on each change - that's one of its defining features. I haven't seen noticable delays with "normal" regular expressions, though. It could help if you pasted the whole regex in at once. Did you try that? > 2) the ability to colour every match of the pattern in the string - > not only the current one. Several people have asked for this feature and it'll most likely be the first I'll add in a future release. > If this wouldn't be too much trouble? At the moment I'm too busy for new features, only bugfixes if necessary. Cheers, Edi.

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Re: [regex-coach] Apparent crash on complex regex in "Tree" tab
by Edi Weitz 13 Sep '05

13 Sep '05

On Thu, 01 Sep 2005 10:30:12 +0300, era+regex=coach(a)iki.fi wrote: > This is on Ubuntu Linux 5.04, using whatever version was on your > site the day before yesterday in the Linux tarball. It doesn't > appear to understand the --version switch No, the switch isn't advertised either. > but I found an "About ..." dialog box which identifies it as version > 0.6.7. OK, that's the newest version. FWIW, I can't reproduce the problem on a Debian testing system either. Actually, from your error output it looks like some kind of "this is not supposed to happen" thingy which I guess is buried within the internals of the GUI toolkit. Maybe switching to another OpenMotif/Lesstif version will help. Sorry, I can't be more helpful at the moment. > There are other benefits, such as being able to read the list in a > newsreader, via RSS, etc. Sure. Of course, this only works if you actually send your message to the list... :) Cheers, Edi.

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regex-coach September 2005