Email address

^(([^;()[\]\\.,;:@"]+(\.[^()[\]\\.,;:@"]+)*)|(".+"))@((([a-z]([-a-z0-9]*[a-z0-9])?)|(#[0-9]+)|(\[((([01]?[0-9]{0,2})|(2(([0-4][0-9])|(5[0-5]))))\.){3}(([01]?[0-9]{0,2})|(2(([0-4][0-9])|(5[0-5]))))\]))\.)*(([a-z]([-a-z0-9]*[a-z0-9])?)|(#[0-9]+)|(\[((([01]?[0-9]{0,2})|(2(([0-4][0-9])|(5[0-5]))))\.){3}(([01]?[0-9]{0,2})|(2(([0-4][0-9])|(5[0-5]))))\]))$

Assert position at the start of the string
Match the regular expression below and capture its match into backreference number 1
- Match either the regular expression below (attempting the next alternative only if this one fails)
  - Match the regular expression below and capture its match into backreference number 2
    - Match a single character not present in the list: one of the characters ";()[]\.,:@""
      - Between one and unlimited times, as many times as possible, giving back as needed (greedy)
    - Match the regular expression below and capture its match into backreference number 3
- Or match regular expression number 2 below (the entire group fails if this one fails to match)
  - Match the regular expression below and capture its match into backreference number 4
Match the character "@" literally
Match the regular expression below and capture its match into backreference number 5
Match the regular expression below and capture its match into backreference number 24
Assert position at the end of the string (or before the line break at the end of the string, if any)