/*REXX pgm encodes/decodes/displays ASCII character strings as  (7─bits)  binary string.*/
parse arg $;        if $==''  then $= 'STRING'   /*get optional argument; Use default ? */
say '   input string=' $                         /*display the input string to terminal.*/
out= comp($);       say ' encoded string='  out  /*encode─► 7─bit binary string; display*/
ori= dcomp(out);    say ' decoded string='  ori  /*decode─► 8─bit char      "  ;    "   */
exit                                             /*stick a fork in it,  we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
comp:  parse arg x; z=;   do j=1  for length(x)  /*convert─►right-justified 7-bit binary*/
                          z= z || right( x2b( c2x( substr(x, j, 1) )), 7)
                          end   /*j*/;     L= length(z);  return left(z, L+(8-L//8)//8, 0)
/*──────────────────────────────────────────────────────────────────────────────────────*/
dcomp: parse arg x; z=;   do k=1  by 7  to length(x);        _= substr(x, k, 7)
                          if right(_, 1)==' '  then leave;   z= z || x2c( b2x(0 || _) )
                          end   /*k*/;     return z