anchor.diff:  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
  
positive.code: { complete detab }
  program detabprog (input, output);
  const
      ENDFILE = -1;
  
negative.code:         write(chr(c))
  end;
  
  
  { detab -- convert tabs to equivalent number of blanks }
  procedure detab;
  const
  