Use DO WHILE to read in every word in a string

%local cnt tword ntot1;

%let cnt=1;
%let tword=%qscan(&tstring,&cnt,%str( ));
%* let ntot1=%qscan(&tcount,&cnt,%str( ));

%do %while(&tword ne);

      data _null_;
            set &dir..&dsn;
            if &tname="&tword";
            call symput('twlbl',trim(left(&tlname)));
      run;

      %concat; *** Macro program is appended after Macro descrip;

      %let cnt=%eval(&cnt+1);
      %let tword=%qscan(&tstring,&cnt,%str( ));
      %* let ntot1=%qscan(&tcount,&cnt,%str( ));

%end; *** End of While(tword ne);

%let cnt=%eval(&cnt-1);