# Cldr Collation
A NIF-based Unicode collator based upon the Unicode library `libicu4c`. Builds upon the
erlang library [erlang-ucol](https://github.com/barrel-db/erlang-ucol) by Benoit Chesneau <benoitc@e-engura.org> and Nicolas Dufour <nrdufour@gmail.com>
This initial version uses only the "root" locale collator which is the [CLDR DUCET collator](http://userguide.icu-project.org/collation).
## Installation
`ex_cldr_collation` depends upon [libicu](https://unicode-org.github.io/icu/userguide/icu/) to provide the underlying collator. There are two required components:
* At *build* time (compilation), the `libicu` development headers are are required. On MacOS these headers are provided as part of the library. For Linux systems the package typically called `libicu-dev` is required.
* At *runtime* the `libicu` library is required. On MacOS and Ubuntu this library is delivered as part of the OS. For Alpine and Debian the `icu` package needs to be installed.
### Installation on MacOS
On MacOS, the relevant headers are included in `ex_cldr_collation` and no additional installation is required.
### Installation on Linux
On Linux systems, `libicu-dev`, `libicu` and `pckconf` must be installed and well as basic development tools for the build process.
```bash
# For Ubuntu
# libicu is required for compiling the NIF
# assumes libicu is already installed which is normal on Ubuntu
$ sudo apt-get install pkgconf libicu-dev
# For Alpine
# icu-dev is required when compiling the NIF
# icu is required at runtime
$ apk add pkgconf icu-dev icu
# Then check that the libicu package dependencies
# can be resolved
$ pkg-config --libs icu-uc icu-io
-licuio -licui18n -licuuc -licudata
```
### Installing ex_cldr_collation
The package can then be installed by adding `cldr_collation` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:ex_cldr_collation, "~> 0.7.0"}
]
end
```
## Examples
```elixir
# Sorting using Cldr.Collator.sort/2
iex> Cldr.Collation.sort(["á", "b", "A"], casing: :sensitive)
["A", "á", "b"]
iex> Cldr.Collation.sort(["á", "b", "A"], casing: :insensitive)
["á", "A", "b"]
# Comparing strings
iex> Cldr.Collation.compare("a", "A", casing: :insensitive)
:eq
iex> Cldr.Collation.compare("a", "A", casing: :sensitive)
:lt
# Using Elixir 1.10 Enum.sort
# Cldr.Collation.Sensitive, Cldr.Collation.Insensitive
# comparise modules are provided
iex> Enum.sort(["AAAA", "AAAa"], Cldr.Collation.Insensitive)
["AAAA", "AAAa"]
iex> Enum.sort(["AAAA", "AAAa"], Cldr.Collation.Sensitive)
["AAAa", "AAAA"]
```