do                       Action Indicator for WHILE, FOR, WITH Statements

 for <index> := <low> to <high> do          { FOR }
   <statement>;

 for <index> := <high> downto <low> do
   <statement>;

 while <bool exp> do                        { WHILE }
   <statement>;

 with <rnames> do                           { WITH }
   <statement>;

    DO precedes the statement to be executed in a WHILE loop, a FOR loop,
    or a WITH statement. DO is always followed by a single statement; for
    multiple statements, you must use a compound statement, as shown
    below:

         while <bool exp> do begin
           <statement>;
           ...;
           <statement>
         end;