# `Localize.Message.MF1.Gettext.Interpolation`
[🔗](https://github.com/elixir-localize/localize_mf1/blob/main/lib/localize/message/mf1/gettext/interpolation.ex#L2)

A Gettext interpolation module for ICU MessageFormat 1 messages.

A Gettext backend that names this module as its `:interpolation` formats
its messages, the msgids and msgstrs of its `.po` files, as MF1 with
`Localize.Message.MF1`, in the locale of `Localize.get_locale/0`:

```elixir
defmodule MyApp.Gettext do
  use Gettext.Backend,
    otp_app: :my_app,
    interpolation: Localize.Message.MF1.Gettext.Interpolation
end
```

Gettext is then used as usual:

```elixir
use Gettext, backend: MyApp.Gettext

gettext("You have {count, plural, one {# message} other {# messages}}", count: 3)
#=> "You have 3 messages"
```

This replaces a module defined with `use Cldr.Gettext.Interpolation,
cldr_backend: MyApp.Cldr` in `ex_cldr_messages`; Localize has no backend
modules, so there is nothing to configure. Messages written in
MessageFormat 2 use `Localize.Gettext.Interpolation` instead.

A translation in the backend's `.po` files that is not valid MF1 is a
compile error of the backend. Any other message that cannot be parsed or
formatted is logged and returned unchanged, and a missing binding is reported to Gettext with the argument written back
in its source form, as in `{count, number}`.

---

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