/*

Binding levels:

0 = lowest

1 = arrows (> lowest)

2 = word (> arrows)

3 = juxta, idword, subword (> word)

*/

static S snlFromTree(Lisp t) {

  ret snlFromTree(t, 0, null);

}

static S snlFromTree(Lisp t, int level, S arrow) {

  if (t == null) ret "";

  if (t.isEmpty()) ret t.head;

  if (t.isA("<"))

    ret snlFromTree_wrap(level, eq(arrow, "<") ? 1 : 0, snlFromTree(t.get(0), 2, null) + " < "+ snlFromTree(t.get(1), 1, "<"));

  if (t.isA(">"))

    ret snlFromTree_wrap(level, eq(arrow, ">") ? 1 : 0,  snlFromTree(t.get(0), 2, null) + " > "+ snlFromTree(t.get(1), 1, ">"));

  // it's a juxtaposition

  new L<S> l;

  int i = 0;

  for (S tok : codeTokensOnly(javaTok(t.head))) {

    if (eq(tok, "*") && i < t.size())

      tok = snlFromTree(t.get(i++), 2, null);

    l.add(tok);

  }

  ret snlFromTree_wrap(level, 1, join(" ", l));

}

static S snlFromTree_wrap(int outer, int inner, S s) {

  if (inner < outer) ret "[" + s + "]";

  ret s;

}