/*
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;
}