I know that this probably have been done zillions of times, but I have the nasty habit of reinventing some wheels (because I think it's the best way to learn), so I'd like to hear your opinions about this:

I have a RegEx that evaluates a form field to see if it's a "valid" e-mail address. So, I came to this: 
([a-z]|[0-9])+((\.)+([a-z]|[0-9])+)*(\-|\_)*([a-z]|[0-9])*\@{1}([a-z]|
+[0-9])+\.{1}([a-z]|[0-9]){2,}(\.([a-z|0-9]){2})*

[download]
Allow me to humbly explain each chunk:
  1. ([a-z]|[0-9])+ : One or more letters and/or numbers
  2. ((\.)+([a-z]|[0-9])+)* : Possibly a dot. Considering that there is a dot one or more letters and/or numbers must follow
  3. (\-|\_)* : Possibly a dash or underscore.
  4. ([a-z]|[0-9])* : Possibly more letters and/or numbers
  5. \@{1} : Must have one (and only one) '@'
  6. ([a-z]|[0-9])+ : Must have more letters and /or numbers followed by
  7. \.{1} : a dot that must be followed by
  8. ([a-z]|[0-9]){2,} : at least two letters and/or numbers
  9. (\.([a-z|0-9]){2})* : and possibly followed by a dot and more letters and/or numbers
So, my questions are:
  1. Have I forgot something here?
  2. Is there anything more that I could or should add?
Please don't send any ready-made regexes as I'm trying to really build this on my own.

Thanks in advance for your comments,


Er Galvão Abbott
www.galvao.eti.br
Porto Alegre Perl Mongers

In reply to Please evaluate: RegEx for validating e-mail addresses by DaWolf

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