Conditional 'required' option about slop

[leejarvis]

There's not an easy or nice built in way to do this. You could create a custom option class like this:

require "slop"

class CustomStringOption < Slop::StringOption
  def finish(opts)
    required_option = opts.options.find do |o|
      o.flags.include?(config[:requires])
    end
    return unless required_option

    raise Slop::MissingRequiredOption unless required_option.value
  end
end

opts = Slop.parse do |o|
  o.custom_string "-a", requires: "-b"
  o.string "-b"
end

Note that the custom option would be on "a" rather than "b", because the finish method on the "b" option will never be called if the option is not provided, so we can't leverage that.

This works by checking the value of option "-b" after the parser has completed its work. If the option is nil (the default for no value provided), then Slop::MissingRequiredOption will be raised.

Alternatively, you could also just check for the presence of your flag name in ARGV or other source Array you're parsing.

[akun1]

Ahh, thank you very much for the solution and a quick reply!