Using ruby's OptionParser to parse sub-commands

Question

I\'d like to be able to use ruby\'s OptionParser to parse sub-commands of the form

COMMAND [GLOBAL FLAGS] [SUB-COMMAND [SUB-COMMAND FLAGS]]

lik

Answer 1

It looks like the OptionParser syntax has changed some. I had to use the following so that the arguments array had all of the options not parsed by the opts object.

begin
  opts.order!(arguments)
rescue OptionParser::InvalidOption => io
  # Prepend the invalid option onto the arguments array
  arguments = io.recover(arguments)
rescue => e
  raise "Argument parsing failed: #{e.to_s()}"
end

Answer 2

Figured it out. I need to use OptionParser#order!. It will parse all the options from the start of ARGV until it finds a non-option (that isn't an option argument), removing everything it processes from ARGV, and then it will quit.

So I just need to do something like:

global = OptionParser.new do |opts|
  # ...
end
subcommands = { 
  'foo' => OptionParser.new do |opts|
     # ...
   end,
   # ...
   'baz' => OptionParser.new do |opts|
     # ...
   end
 }

 global.order!
 subcommands[ARGV.shift].order!

Answer 3

There are also other gems you can look at such as main.

Answer 4

GLI is the way to go, https://github.com/davetron5000/gli. An excerpt from a tutorial:

#!/usr/bin/env ruby
require 'gli'
require 'hacer'

include GLI::App

program_desc 'A simple todo list'

flag [:t,:tasklist], :default_value => File.join(ENV['HOME'],'.todolist')

pre do |global_options,command,options,args|
  $todo_list = Hacer::Todolist.new(global_options[:tasklist])
end

command :add do |c|
  c.action do |global_options,options,args|
    $todo_list.create(args)
  end
end

command :list do |c|
  c.action do
    $todo_list.list.each do |todo|
      printf("%5d - %s\n",todo.todo_id,todo.text)
    end
  end
end

command :done do |c|
  c.action do |global_options,options,args|
    id = args.shift.to_i
    $todo_list.list.each do |todo|
      $todo_list.complete(todo) if todo.todo_id == id
    end
  end
end

exit run(ARGV)

You can find the tutorial at http://davetron5000.github.io/gli/.