in reply to email regex

This isn't a regex but is one way to do it: 
#!/usr/bin/perl -w
use strict;

use CGI ':standard';


my $email = param('email');

(my $name, my $domain)=split(/\@/, $email);

print "Content-type: text/html\n\n";
print "$name";

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Re: email regex
by Abigail-II (Bishop) on Aug 19, 2003 at 11:23 UTC
    Eh, no, it doesn't. As I said in an earlier reply, email addresses can be complicated. Here's an example were your approach will fail: 
        "@"@example.com

    [download]

    Abigail

[reply]
[d/l]
      Okay, looking at this in another light ... How does this substitution, which in theory strips the domain and route portion of the email address, fair.

      ( $domain ) = $email =~ /\@([^\@]+)$/;

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      Note that this substitution does not handle RFC822 addresses which contains elements beyond the local_part@domain atoms (however this may be considered beyond the scope of this question).

      Update - Okay, updated using a subset of the RFC822 email address regular expression from Mastering Regular Expressions to strip off the trailing domain portion to leave the "username" element ...

      $email =~ s/(?:\@[\040\t]*(?:(?:[^(\040)<>@,;:"\\\[\]\000-\037\x80-\xf
+f]|(?:\[(\040)<>@,;:"\\\[\]\000-\037\x80-\xff]))+(?!(?:[^(\040)<>@,;:
+"\\\[\]\000-\037\x80-\xff]|(?:\[(\040)<>@,;:"\\\[\]\000-\037\x80-\xff
+])))|\[(?:[^\\\x80-\xff\n\015\[\]]|\\[^\x80-\xff])*\])[\040\t]*(?:\([
+^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\\\x80-\xff\n\015()]*(
+?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\\x80-\xff\n\015()]*)*
+\)[\040\t]*)*(?:\.[\040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80
+-\xff]|\([^\\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015(
+)]*)*\))[^\\\x80-\xff\n\015()]*)*\)[\040\t]*)*(?:(?:[^(\040)<>@,;:"\\
+\[\]\000-\037\x80-\xff]|(?:\[(\040)<>@,;:"\\\[\]\000-\037\x80-\xff]))
++(?!(?:[^(\040)<>@,;:"\\\[\]\000-\037\x80-\xff]|(?:\[(\040)<>@,;:"\\\
+[\]\000-\037\x80-\xff])))|\[(?:[^\\\x80-\xff\n\015\[\]]|\\[^\x80-\xff
+])*\])[\040\t]*(?:\([^\\\x80-\xff\n\015()]*(?:(?:\\[^\x80-\xff]|\([^\
+\\x80-\xff\n\015()]*(?:\\[^\x80-\xff][^\\\x80-\xff\n\015()]*)*\))[^\\
+\x80-\xff\n\015()]*)*\)[\040\t]*)*)*)$//;

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      perl -le 'print+unpack"N",pack"B32","00000000000000000000001001111011"'

[reply]
[d/l]
[select]
        How does this substitution, which in theory strips the domain and route portion of the email address, fair

        I think you already answered your own question:

        Note that this substitution does not handle RFC822 addresses which contains elements beyond the local_part@domain atoms

        So, you tell us. For which (subset of RFC822?) email addresses does your regexp work?

        Abigail

[reply]
Re: Re: email regex
by tbone1 (Monsignor) on Aug 19, 2003 at 13:03 UTC
    If you'll pardon the self-promotion, check out this discussion for why that won't always work.

    --
    tbone1
    Ain't enough 'O's in 'stoopid' to describe that guy.
    - Dave "the King" Wilson

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