static void insertionSort_(List a, int left, int right, int compare(a, b)) {
  for (int i = left + 1; i <= right; i++) {
    var el = a[i];
    int j = i;
    while ((j > left) && (compare(a[j - 1], el) > 0)) {
      a[j] = a[j - 1];
      j--;
    }
    a[j] = el;
  }
}

Sorts all elements of the given list a according to the given compare function.

The compare function takes two arguments x and y and returns -1 if x < y, 0 if x == y, and 1 if x > y.

The function's behavior must be consistent. It must not return different results for the same values.

static void sort(List a, int compare(a, b)) {
  _doSort(a, 0, a.length - 1, compare);
}

Sorts all elements in the range from (inclusive) to to (exclusive) of the given list a.

If the given range is invalid an "OutOfRange" error is raised. TODO(floitsch): do we want an error?

See sort for requirements of the compare function.

static void sortRange(List a, int from, int to, int compare(a, b)) {
  if ((from < 0) || (to > a.length) || (to < from)) {
    throw "OutOfRange";
  }
  _doSort(a, from, to - 1, compare);
}