Required keyword arguments

Required keyword arguments were introduced in Ruby 2.1, as an improvement to keyword arguments.

To define a keyword argument as required, simply declare the argument without a default value.

def say(message:)
  puts message
end

say
# => ArgumentError: missing keyword: message

say message: "Hello World"
# => "Hello World"

You can also mix required and non-required keyword arguments:

def say(before: "<p>", message:, after: "</p>")
  puts "#{before}#{message}#{after}"
end

say
# => ArgumentError: missing keyword: message

say message: "Hello World"
# => "<p>Hello World</p>"

say message: "Hello World", before: "<span>", after: "</span>"
# => "<span>Hello World</span>"

Found a mistake? Have a question or improvement idea? Let me know.

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