Argsy

Tiny helper snippet you can paste into your CLI script(s) to obtain "commands + options" DSL without external dependencies.

Rationale

As you already know, Ruby is awesome for scripting and any sort of CLI tools: it gives you a superb OS commands interaction interface, JSON/YAML parsing, HTTP tools, etc... All out of the box! But built-in OptionParser doesn't provide easy-to-write functionality to create CLIs like ./script command --option 1. The problem here is: how to declare command, action and options conveniently?

Sometimes, for any imaginable reason, you do not want you script to be dependent on external gems (say, you want to pass a script that "just works!" to your co-workers without telling them "Hey, you also need to install this or that gem")

Argsy gives you such possibility. It's just 17 lines of code, published under The Unlicense, so you can just copy-paste it inside your script and have a nice tiny DSL. You can of course use it as a gem as well, if you want to.

Disclaimer: Argsy doesn't claim itself as a profound CLI DSL like Thor and the company, thus for complex scripts, please, opt for those gems instead.

Usage

Argsy.new '1.0.0' do
  command :list, 'List all files' do
    action do |o|
      puts %w(. .. .hidden.py).join("\n") if o[:all]
      puts %w(todos.txt recipes.doc).join("\n")
      puts "me.#{o[:extension]}" if o[:extension]
    end
    options do
      on '-a', '--all', 'Show all, even hidden files'
      on '-e', '--extension EXTENSION', 'List available files with extension'
    end
  end

  command 'print', 'Print all given options' do
    action &method(:puts)
    options do
      on '-a', '--A', 'A option'
      on '-b', 'B option'
    end
  end

  command 'hello:world', 'Greet the World group without options' do
    action { puts 'Hello world!' }
  end

  command :post do |c|
    action do |opts|
      puts "I'm a command without description"
      puts "Posting to facebook: #{opts[:message]}" if opts[:facebook]
      puts "Posting to twitter: You're Tearing Me Apart, Lisa!" if opts[:twitter]
      puts "Date and time posted: #{opts[:date]}"
    end
    options do
      require 'optparse/time'
      on_tail '-d', '--date=DATE', Time, 'Date when message was posted'
      on '-f', '--facebook' do
        c.opts[:message] = 'Oh, Hi Mark'
      end
      on '-t', '--twitter'
    end
  end
end.run

In console:

$ ./example
Usage: playground CMD [--help] [--version]
    list                             List all files
    print                            Print all given options
    hello                            Greet the World without options
    post                             

$ ./example post --help
Usage: playground post [options] [--help]
    -f, --facebook
    -t, --twitter
    -d, --date=DATE                  Date when message was posted

$ ./example post -f -d 12-8-2016
I'm a command without description
Posting to facebook: Oh, Hi Mark
Date and time posted: 2016-08-12 00:00:00 +0300


$ ./example post --version
example version 1.0.0

FAQ

Q:	A:
Does it support groups/subcommands?	Only in a way of declaring commands as 'group:subcommand'
What can I do inside options block?	Anything that is possible inside a stdlib's OptionParser
Why not Thor, Commander, etc.?	See rationale
Can I use it as a gem?	Yes. gem install argsy
Why does it look like a minified jQuery?	Yes, it's not an idiomatic Ruby formatting. I wanted to make it terse, still readable
Copy-pasting is bad. It's not DRY!	Absolutely agree with you

License

The Unlicense