Barely touch regexes these days because for last few years I've been using Rebol / Red parse more and more.

Here's a translation of the first SRL example in the parse dialect:

  [
      some [number | letter | symbol]                 
      "@"
      some [number | letter | "-" ]                   
      some ["." copy tld some [number | letter | "-" ]]
      if (parse tld [letter some letter])
  ]

And here's a full matching example:

  number: charset "0123456789"
  letter: charset [#"a" - #"z"]
  symbol: charset "._%+-"
  
  s: {Message me at you@example.com. Business email: business@awesome.email}
  
  parse s [ 
    any [
        copy local some [number | letter | symbol]
        "@" 
        copy domain [
            some [number | letter | "-" ] 
            some ["." copy tld some [number | letter | "-" ]]
        ]   
        if (parse tld [letter some letter])
        (print ["local:" local "domain:" domain])

        | skip
    ]   
  ]

Some parse links:

* http://blog.hostilefork.com/why-rebol-red-parse-cool/

* https://en.wikibooks.org/wiki/REBOL_Programming/Language_Fea...

* http://www.codeconscious.com/rebol/parse-tutorial.html

* http://www.red-lang.org/2013/11/041-introducing-parse.html