Functions to implement the ordinal rule-based-number-format rules of CLDR.

As CLDR notes, the data is incomplete or non-existent for many languages. It is considered complete for English however.

The standard public API for RBNF is via the Cldr.Number.to_string/2 function.

The functions on this module are defined at compile time based upon the RBNF rules defined in the Unicode CLDR data repository. Available rules are identified by:

iex> Cldr.Print.Backend.Rbnf.Ordinal.rule_sets("en")
[:digits_ordinal]

A rule can then be invoked on an available rule_set. For example

iex> Cldr.Print.Backend.Rbnf.Ordinal.digits_ordinal(123, "en")
"123rd"

This call is equivalent to the call through the public API of:

iex> Cldr.Print.Backend.Number.to_string(123, format: :ordinal)
{:ok, "123rd"}