anchor.diff: -{ complete detab }
  +{ complete detab, without tabstops and settabs }
   program detabprog (input, output);
   const
       ENDFILE = -1;
  
positive.code:             repeat
                  putc(BLANK);
                  col := col + 1
              until (col mod TABSPACE = 1)
          else if (c = NEWLINE) then begin
              putc(NEWLINE);
              col := 1
  
negative.code: var
      c : character;
      col : integer;
  
  { tabpos -- return true if col is a tab stop }
  function tabpos (col : integer) : boolean;
  begin
      if (col > MAXLINE) then
          tabpos := true
      else
          tabpos := (col mod TABSPACE = 1)
  end;
  
  begin
      col := 1;
      while (getc(c) <> ENDFILE) do
  