# `Cldr.Gettext.Interpolation`
[🔗](https://github.com/elixir-cldr/cldr_messages/blob/v2.0.1/lib/cldr/gettext/interpolation.ex#L1)

As of [Gettext 0.19](https://hex.pm/packages/gettext/0.19.0), `Gettext`
supports user-defined [interpolation modules](https://hexdocs.pm/gettext/Gettext.html#module-backend-configuration).
This makes it easy to combine the power of ICU message formats with the
broad `gettext` ecosystem and the inbuilt support for `gettext`
in [Phoenix](https://hex.pm/packages/phoenix).

The documentation for [Gettext](https://hexdocs.pm/gettext/Gettext.html#content)
should be followed with considerations in mind:

1. A Gettext backend module should use the `:interpolation` option
   defined referring to the `ex_cldr_messages` backend you have defined.
2. The message format is in the ICU message format (instead of the Gettext format).

### Defining a Gettext Interpolation Module

Any [ex_cldr](https://hex.pm/packages/ex_cldr) [backend module](https://hexdocs.pm/ex_cldr/readme.html#backend-module-configuration) that has a `Cldr.Message` provider configured can be used as an interpolation module. Here is an example:
```elixir
# CLDR backend module
defmodule MyApp.Cldr do
  use Cldr,
    locales: ["en", "fr", "ja", "he", "th", "ar"],
    default_locale: "en",
    providers: [Cldr.Number, Cldr.DateTime, Cldr.Unit, Cldr.List, Cldr.Calendar, Cldr.Message],
    gettext: MyApp.Gettext,
    message_formats: %{
      USD: [format: :long]
    }
end

# Define an interpolation module for ICU messages
defmodule MyApp.Gettext.Interpolation do
  use Cldr.Gettext.Interpolation, cldr_backend: MyApp.Cldr

end

# Define a gettext module with ICU message interpolation
defmodule MyApp.Gettext do
  use Gettext, otp_app: :ex_cldr_messages, interpolation: MyApp.Gettext.Interpolation
end

```
Now you can proceed to use `Gettext` in the normal manner, most
typically with the `gettext/3` macro.

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*Consult [api-reference.md](api-reference.md) for complete listing*