Options

An option is a named argument that is passed after the command name and the arguments.

For instance, given the foo request command, when an user types foo request --mode=http2, then --mode=http2 is considered an option.
A command can accept none or many options.

#!/usr/bin/env ruby
require "bundler/setup"
require "dry/cli"

module Foo
  module CLI
    module Commands
      extend Dry::CLI::Registry

      class Request < Dry::CLI::Command
        option :mode, default: "http", values: %w[http http2], aliases: ["-m"], desc: "The request mode"

        def call(**options)
          puts "Performing a request (mode: #{options.fetch(:mode)})"
        end
      end

      register "request", Request
    end
  end
end

Dry::CLI.new(Foo::CLI::Commands).call

$ foo request
Performing a request (mode: http)

$ foo request --mode=http2
Performing a request (mode: http2)

$ foo request --m=http2
Performing a request (mode: http2)

$ foo request --mode=unknown
ERROR: "foo request" was called with arguments "--mode=unknown"