Arguments
An argument is a token passed after the command name.
For instance, given the foo greet command, when an user types foo greet Luca, then Luca is considered an argument.
A command can accept none or many arguments.
An argument can be declared as required.
#!/usr/bin/env ruby
require "bundler/setup"
require "dry/cli"
module Foo
module CLI
module Commands
extend Dry::CLI::Registry
class Greet < Dry::CLI::Command
argument :name, required: true, desc: "The name of the person to greet"
argument :age, desc: "The age of the person to greet"
def call(name:, age: nil, **)
result = "Hello, #{name}."
result = "#{result} You are #{age} years old." unless age.nil?
puts result
end
end
register "greet", Greet
end
end
end
Dry::CLI.new(Foo::CLI::Commands).call
$ foo greet Luca
Hello, Luca.
$ foo greet Luca 35
Hello, Luca. You are 35 years old.
$ foo greet
ERROR: "foo greet" was called with no arguments
Usage: "foo greet NAME"