
   ret = yylex();   
   switch(ret)
       {
   case SET:
       /* Next input should be the numeric value */
       ret = yylex();
       if (ret != INTEGER_NUMBER)
           {
           printf("\n ERROR -- number not specified
                  after SET");
           exit(0);
           }
       else
           sscanf(yytext,"%d",&value);
       break;
       ...

