Interpolation

Arguments and NamedTuple

Interpolations can be passed as arguments for the t method:

Rosetta.find("user.welcome_message").t(name: "Ary")
# => "Hi Ary!"

A NamedTuple works as well:

Rosetta.find("user.welcome_message").t({name: "Ary"})
# => "Hi Ary!"

Important to know here is that translations with interpolation keys will always require you to call the t method with the right number of interpolation keys, or the compiler will complain:

# en.user.welcome_message: "Hi %{name}!"
Rosetta.find("user.welcome_message").t

Error: wrong number of arguments for 'Rosetta::Locales::User_WelcomeMessage#t'
(given 0, expected 1)

Overloads are:
 - Rosetta::Locales::User_WelcomeMessage#t(name : String)
 - Rosetta::Locales::User_WelcomeMessage#t(values : NamedTuple(name: String))

This is to ensure you're not missing any interpolation values.

Time directives

If the string in your locale files contains time format directives, Rosetta will require a time object as one of the interpolation arguments and translate the value to the current locale:

# es.messages.great_day: "¡Hola %{name}, que tengas un buen %A!"
Rosetta.find("messages.great_day").t(name: "Brian", time: Time.local)
# => "¡Hola Brian, que tengas un buen domingo!"

Working with a Hash

The t method does not accept hashes, only arguments or a NamedTuple. For situations where you have to use a hash, there's the t_hash method:

Rosetta.find("user.welcome_message").t_hash({ :name => "Beta" })
# => "Hi Beta!"

Warning

This method is considered unsafe because the content of hashes can't be checked at compile-time. It's also much slower, because interpolation values are inserted using gsub instead of native string interpolation. So, only use it when there's no other way, and use it with care.

The uninterpolated string

The raw, uninterpolated string, can be accessed with the raw method:

Rosetta.find("user.welcome_message").raw
# => "¡Hola %{name}, que tengas un buen %A!"

Which can then be interpolated later:

value = Rosetta.find("messages.great_day").raw
# => "¡Hola %{name}, que tengas un buen %A!"
Rosetta.interpolate(value, {name: "Ary", time: Time.local})
# => "¡Hola Ary, que tengas un buen domingo!"

Warning

The Rosetta.interpolate method uses gsub rather than native string interpolation, so it's a lot slower and it doesn't check if all the required interpolation keys are given.