anchor.diff:          write(chr(c))
   end;
   
  +
   { detab -- convert tabs to equivalent number of blanks }
   procedure detab;
   const
  
positive.code: { complete detab }
  program detabprog (input, output);
  const
      ENDFILE = -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
  