Hi Michael,

> Has anyone compiled a collection of 'common' regular expression 
> patterns.

Never heard of such a list.  The O'Reilly book "Mastering Regular 
Expressions" probably contains a whole lot.

> - valid email addresses

Short answer:  /^\w+\@[\w\.]+\w+$/

Take an email address:  "joe97_smith / some.domain.org"

1) The email starts with "word" characters (letters, underscores and 
numbers):

      Word character
       |
    /^\w+/
     |
    Start

2) Followed by an "@" symbol.

   /^\w+\@/

3) Followed by a collection of word characters and dots and ending in word 
characters.

                   End of the string.
                    |
   /^\w+\@[\w\.]+\w+$/
          \____/
            |
         New class containing either word characters or dots.
   

Similarly, you can construct REs for other tasks.

> - valid http address
> - etc.
> 
> TIA
> 
> -Michael Garriss
> 
> 

-- 
Daniel Carrera
Graduate Teaching Assistant.  Math Dept.
University of Maryland.  (301) 405-5137