Protocol for converting an arbitrary value to a Localize.PersonName struct.

This protocol is an alternative to implementing the Localize.PersonName behaviour. Any value — typically a struct — can gain person name formatting support by providing a protocol implementation that returns a Localize.PersonName.t/0:

defimpl Localize.PersonName.Convertible, for: MyApp.Customer do
  def to_person_name(customer) do
    %Localize.PersonName{
      given_name: customer.first_name,
      surname: customer.last_name,
      locale: customer.locale
    }
  end
end

With the implementation in place, formatter functions such as Localize.PersonName.to_string/2 and Localize.PersonName.to_iodata/2 accept the value directly:

Localize.PersonName.to_string(customer, format: :long)

The formatter first looks for a protocol implementation. If none is found, it falls back to the Localize.PersonName behaviour.

When to choose the protocol over the behaviour

The protocol is preferred when:

• The struct's module is owned by a third party — protocol implementations can live in the consuming application without modifying the struct's module.

• You want to keep formatting concerns in a dedicated file, separate from the struct definition.

• The conversion is best expressed as a single function that builds a Localize.PersonName struct, rather than a handful of per-field accessor callbacks.

The behaviour is preferred when the struct's module is under your control and you want each name field to be accessible as its own module function (for use cases beyond this library).