Проверить строку на правильность Email адреса

function
 MailURLMayBeInvalid(const
 s: string
): Boolean;
 var

   i: Integer;
   c: string
;
 begin
 // ' ', a, o, u, ?, [, ], (, ), : in EMail-Address 
  Result := (Trim(s) = '') or
 (Pos(' ', AnsiLowerCase(s)) > 0) or

     (Pos('a', AnsiLowerCase(s)) > 0) or
 (Pos('o', AnsiLowerCase(s)) > 0) or

     (Pos('u', AnsiLowerCase(s)) > 0) or
 (Pos('?', AnsiLowerCase(s)) > 0) or

     (Pos('[', AnsiLowerCase(s)) > 0) or
 (Pos(']', AnsiLowerCase(s)) > 0) or

     (Pos('(', AnsiLowerCase(s)) > 0) or
 (Pos(')', AnsiLowerCase(s)) > 0) or

     (Pos(':', AnsiLowerCase(s)) > 0);
   if
 Result then
 Exit; // @ not in EMail-Address; 
  i      := Pos('@', s);
   Result := (i = 0) or
 (i = 1) or
 (i = Length(s));
   if
 Result then
 Exit;
   Result := (Pos('@', Copy(s, i + 1, Length(s) - 1)) > 0);
   if
 Result then
 Exit; // Domain <= 1 
  c      := Copy(s, i + 1, Length(s));
   Result := Length(c) <= 1;
   if
 Result then
 Exit;
   i      := Pos('.', c);
   Result := (i = 0) or
 (i = 1) or
 (i = Length(c));
 end
;

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