sbool lispCalculateDeep_debug;

sclass lispCalculateDeep_Op {
  int arity;
  O function;
  
  *() {}
  *(int *arity, O *function) {}
}

static new Map<S, lispCalculateDeep_Op> lispCalculateDeep_ops;

static {
  lispCalculateDeep_op(f plus, "sppxbuuqeetjmzuo", "jcnbmtmfzktxhzyf");
  lispCalculateDeep_op(f minus, "jxcubqjtqykhfvyo");
  lispCalculateDeep_op(f bigIntBiggerThan, "wdbphzfoxwlrhdyl");
}

// evaluate anywhere in the tree (e.g. Fib number 2-1 => Fib number 1)
static Lisp lispCalculateDeep(Lisp x) {
  ret lispMap_after(x, func(Lisp l) {
    if (lispCalculateDeep_debug) print("lispCalculateDeep: " + l);
    
    lispCalculateDeep_Op op = lispCalculateDeep_ops.get(l.head);
    if (op == null) null;
    int n = op.arity;
    if (n != l.size()) null;
    for (Lisp arg : l) if (!lispIsInt(arg)) null;
    O[] args = new O[n];
    for i to n: args[i] = lispToInt(l.get(i));
    O o = callFOpt(op.function, args);
    // if (o == null) null;
    if (o instanceof BigInteger) ret lispInt((BigInteger) o);
    if (o instanceof Bool) ret lispBool((Bool) o);
    warn("lispCalculateDeep badly defined operation: " + l.head);
  });
}

static void lispCalculateDeep_op(S function, S... names) {
  putWithAllKeys(lispCalculateDeep_ops, names, new lispCalculateDeep_op(2, function));
}