static IntRange tok_findArgs(LS tok) {
  ret tok_findArgs(tok, getBracketMap(tok));
}
  
static IntRange tok_findArgs(LS tok, Map<Int> bracketMap) {
  ret tok_findArgs(tok, 0, bracketMap);
}

static IntRange tok_findArgs(LS tok, int i, Map<Int> bracketMap) {
  i = indexOfAny(tok, i, "(", "{");
  if (i < 0) null;
  if (eq(get(tok, i), "{")) null;
  int start = (i += 2);
  while (i < l(tok)-2 && neq(get(tok, i), ")")) {
    Int j = bracketMap.get(i);
    if (j != null) continue with i = j+2;
    i += 2;
  }
  ret intRange(start-1, i);
}

Began life as a copy of #1015569