Parsing Options

Integration with optarg

Crystal CLI integrates its APIs with optarg. optarg is a library for parsing command-line options and arguments.

Once you define a command class, the class automatically have an optarg's model class that is named Options. You can define options and arguments inside the Options class.

class Smile < Cli::Command
  class Options
    bool "--say-hello"
  end
end

To access parsed values in a running context, use the following methods:

• options
• args
• named_args
• nameless_args
• parsed_args
• unparsed_args

These methods are proxy methods and internally invoke the corresponding optarg's API methods. The method names are the same as the optarg API.

class Smile < Cli::Command
  class Options
    bool "--say-hello"
  end

  def run
    puts "hello" if options.say_hello?
    puts ":)"
  end
end

Smile.run %w(--say-hello)

This prints:

hello
:)