Function IsValidEmail for Delphi

It's hard to believe, but there is no standard function in Delphi to verify the email address. Also there is no native RegExp support. So I have to create own routine for email verification. It is not fully RFC compatible (there is no support for user@[10.20.30.40] and John Dow <a@b.c>) but is good enough for 99% of end-user programs.

//------------------------------------------------------------------------------ // Verifies is the given string valid email address or not. Domain names without // dots (user@localhost) are acceptable if AllowRootDomain is True. function IsValidEmail(const Value: string; AllowRootDomain: Boolean = False): Boolean; //------------------------------------- function _Verify(const S: string): Boolean; var i: Integer; begin Result := False; for i := 1 to Length(S) do if not (S[i] in ['a'..'z' ,'A'..'Z', '0'..'9', '_', '-', '.']) then Exit; Result := True; end;{Internal _Verify} //------------------------------------- var i: Integer; User, Domain: string; begin Result:= False; // @ is must, but not first i := Pos('@', Value); if i < 2 then Exit; User := Copy(Value, 1, i - 1); if User = '' then Exit; Domain := Copy(Value, i + 1, MaxInt); if Domain = '' then Exit; if not AllowRootDomain then begin // Dot is must, but not first i := Pos('.', Domain); if i < 2 then Exit; end; // Dot should not be first and the last if (Domain[1] = '.') or (Domain[Length(Domain)] = '.') then Exit; // Verify each char of User and Domain Result:= _Verify(User) and _Verify(Domain); end;

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P.S. Does anybody use Delphi in 2011? :)