$use Arithm StdIO Vector;

$func Perm s = ;

$vector V;
$const  Len   = 10;
$const  Len-1 = 9;

Main =
  <Vector-Replace &V (1) (2) (3) (4) (5) (6) (7) (8) (9) (0)>,
  <Perm 0>;

Perm sN, {
  sN : &Len-1 = ;
//    <PrintLN <Vector-To-Exp &V>>;
  <"+" sN 1> :: sN1,
    <Perm sN1>,
    <Vector-Ref &V sN> :: e.tmp1,
    sN1 $iter {
      <Vector-Ref &V sM> :: e.tmp2,
        <Vector-Set &V sM e.tmp1>,
        <Vector-Set &V sN e.tmp2>,
        <Perm sN1>,
        <Vector-Set &V sM e.tmp2>,
        <Vector-Set &V sN e.tmp1>,
        <"+" sM 1>;
    } :: sM,
    sM : &Len;
};