thor

Map options to a class. Simply create a class with the appropriate annotations, and have options automatically map to functions and parameters.

Example:

class MyApp < Thor                                                # [1]
  map "-L" => :list                                               # [2]
                                                                
  desc "install APP_NAME", "install one of the available apps"    # [3]
  method_options :force => :boolean, :alias => :optional          # [4]
  def install(name)
    user_alias = options[:alias]
    if options.force?
      # do something
    end
    # ... other code ...
  end
  
  desc "list [SEARCH]", "list all of the available apps, limited by SEARCH"
  def list(search = "")
    # list everything
  end
end

Thor automatically maps commands as such:

app install myname --force

That gets converted to:

MyApp.new.install("myname")
# with {'force' => true} as options hash

1. Inherit from Thor to turn a class into an option mapper
2. Map additional non-valid identifiers to specific methods. In this case, convert -L to :list
3. Describe the method immediately below. The first parameter is the usage information, and the second parameter is the description.
4. Provide any additional options. These will be marshaled from -- and - params. In this case, a --force and a -f option is added.

Types for method_options

:boolean

true if the option is passed

true or false

same as :boolean, but fall back to given boolean as default value

:required

the value for this option MUST be provided

:optional

the value for this option MAY be provided

:numeric

the value MAY be provided, but MUST be in numeric form

a String or Numeric

same as :optional, but fall back to the given object as default value

In case of unsatisfied requirements, Thor::Options::Error is raised.

Examples of option parsing:

# let's say this is how we defined options for a method:
method_options(:force => :boolean, :retries => :numeric)

# here is how the following command-line invocations would be parsed:

command -f --retries 5    # => {'force' => true, 'retries' => 5}
command --force -r=5      # => {'force' => true, 'retries' => 5}
command -fr 5             # => {'force' => true, 'retries' => 5}
command --retries=5       # => {'retries' => 5}
command -r5               # => {'retries' => 5}