Natools

         case C is
            when '(' | 'o' | 'O' =>
               Entity := SE.Printers.Pretty.Opening;
               Valid := True;
            when ')' | 'c' | 'C' =>
               Entity := SE.Printers.Pretty.Closing;
               Valid := True;
            when 'a' | 'A' | 'd' | 'D' | 'x' | 'X' =>
               Entity := SE.Printers.Pretty.Atom_Data;
               Valid := True;
            when others =>
               Valid := False;
         end case;
      end Parse;