public static List<FormulaFunction> valuesAsUserDisplaySortedList() {
        final List<FormulaFunction> list = new ArrayList<>(Arrays.asList(values()));
        Collections.sort(list, (f1, f2) -> TextUtils.COLLATOR.compare(f1.getUserDisplayableString(), f2.getUserDisplayableString()));
        return list;
    }
Maintains all functions available in {@link Formula}'s
main/src/main/java/cgeo/geocaching/utils/formulas/FormulaFunction.java