Comments on: Email Validation Regular Expression http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/ Doing what needs to be done to do a website. Sat, 02 Jan 2010 07:50:55 +0000 http://wordpress.org/?v=2.8.5 hourly 1 By: admin http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/comment-page-1/#comment-20 admin Sat, 06 Oct 2007 08:21:28 +0000 http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/#comment-20 I think it could be worth writing a parser to validate input against a grammar, although largely for the ability to easily plug in a new grammar. Just got to find the time :(. It's a case of investing time up front to save time later on, I hope. I think custom written code runs much the same risk as custom regular expressions. Which you are more comfortable with depends on your experience (and I speak as somebody with 15 years more experience of programming than regular expressions). They generally both need thorough testing and debugging before they are ready. I think it could be worth writing a parser to validate input against a grammar, although largely for the ability to easily plug in a new grammar. Just got to find the time :( . It’s a case of investing time up front to save time later on, I hope.

I think custom written code runs much the same risk as custom regular expressions. Which you are more comfortable with depends on your experience (and I speak as somebody with 15 years more experience of programming than regular expressions). They generally both need thorough testing and debugging before they are ready.

]]> By: NeverFriday » First Issue of Python Magazine!! http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/comment-page-1/#comment-19 NeverFriday » First Issue of Python Magazine!! Sat, 06 Oct 2007 00:04:39 +0000 http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/#comment-19 [...] email address may not work properly so you may not receive “. I actually ran across another regular-expression validation scheme for email addresses yesterday! I told the writer to try and avoid the use of regular expressions because it appears [...] [...] email address may not work properly so you may not receive “. I actually ran across another regular-expression validation scheme for email addresses yesterday! I told the writer to try and avoid the use of regular expressions because it appears [...]

]]> By: Mark Woodman http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/comment-page-1/#comment-18 Mark Woodman Fri, 05 Oct 2007 16:31:12 +0000 http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/#comment-18 Just popping in to say hi. I didn't see any author attributions on your site. Get an About page up for those of us who don't know you. Good luck! - Mark Just popping in to say hi. I didn’t see any author attributions on your site. Get an About page up for those of us who don’t know you.

Good luck!

- Mark

]]> By: Rudolf Olah http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/comment-page-1/#comment-17 Rudolf Olah Thu, 04 Oct 2007 23:45:58 +0000 http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/#comment-17 I just Googled for "LALR PHP" and found this: http://pear.php.net/pepr/pepr-proposal-show.php?id=416 That could be useful. I would still recommend writing a custom function that handles email validation without using regular-expressions. That would be far more educational in my opinion, and far more readable. I just Googled for “LALR PHP” and found this:
http://pear.php.net/pepr/pepr-proposal-show.php?id=416

That could be useful. I would still recommend writing a custom function that handles email validation without using regular-expressions. That would be far more educational in my opinion, and far more readable.

]]> By: admin http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/comment-page-1/#comment-16 admin Thu, 04 Oct 2007 15:20:42 +0000 http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/#comment-16 Firstly, if I were to implement 2822 in the same fashion as I have 822 (as I still intend to) then it will include this as the 822 local-part definition is used in the local-part definition for 2822. I have not yet had time to do 2822. Secondly, the inclusion of the regex formatted for PHP might give you a clue what language I was using when I developed this. I had limited time and could not find a php parser generator in time. Still can't. You don't always have the option, depending on your hosting, to do things in other languages and connect them to PHP neatly. If you can point me in the direction of a parser generator for PHP then I for one would be happy to stop "fucking around with regular expressions" in this case. Firstly, if I were to implement 2822 in the same fashion as I have 822 (as I still intend to) then it will include this as the 822 local-part definition is used in the local-part definition for 2822. I have not yet had time to do 2822.

Secondly, the inclusion of the regex formatted for PHP might give you a clue what language I was using when I developed this. I had limited time and could not find a php parser generator in time. Still can’t. You don’t always have the option, depending on your hosting, to do things in other languages and connect them to PHP neatly. If you can point me in the direction of a parser generator for PHP then I for one would be happy to stop “fucking around with regular expressions” in this case.

]]> By: Rudolf Olah http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/comment-page-1/#comment-15 Rudolf Olah Thu, 04 Oct 2007 14:54:17 +0000 http://blog.websitetodos.com/2007/10/04/email/email-validation-regular-expression/#comment-15 RFC 822 is obsoleted by RFC 2822. It says so right at the top of the RFC. So why not just go straight for RFC 2822 implementation rather than implementing the obsoleted version? In any case, using regular-expressions is stupid for this because they are ugly and unreadable and how do you *really* know that it validates all email addresses properly? If you read the the RFCs, you'll see that there is a language grammar. You can generate a parser/validator using it. Why not hand-code (or generate) a function rather than fucking around with regular-expressions? RFC 822 is obsoleted by RFC 2822. It says so right at the top of the RFC. So why not just go straight for RFC 2822 implementation rather than implementing the obsoleted version?

In any case, using regular-expressions is stupid for this because they are ugly and unreadable and how do you *really* know that it validates all email addresses properly? If you read the the RFCs, you’ll see that there is a language grammar. You can generate a parser/validator using it. Why not hand-code (or generate) a function rather than fucking around with regular-expressions?

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