OptBind

Binds command-line options to variables.

Extends command-line option analysis by wrapping an instance of standard OptionParser. Enables binding of options and arguments to instance or local variables. Provides Hash and String only interfaces to define command line options, unlike a mixed interface by standard library. Supports access to default values and partial argument analysis. Builds Git-like options and help by default.

Installation

bundle install optbind

Usage

Bind local variables to ARGV and parse command line arguments:

require 'optbind'

ARGV                                         #=> ['--no-verbose', '-o', 'file.out', 'file.in']

i, o, v = STDIN, STDOUT, true

ARGV.bind_and_parse! to: :locals do
  use '[<options>] [<file>]'
  use '--help'
  opt 'o -o --output=<file>'
  opt 'v -v --[no-]verbose'
  arg 'i [<file>]'
end

ARGV                                         #=> []

[i, o, v]                                    #=> ['file.in', 'file.out', false]

Use bind or one of its aliases on ARGV instead of bind_and_parse! to be able to parse! command line arguments later:

ARGV.bind to: :locals do
  # ...
end

ARGV.parse!

Create an OptionBinder and use it directly:

binder = OptionBinder.new do
  # ...
end

binder.parse! ARGV

Note that plain OptionBinder.new binds to local variables of top level binding object by default.

See specs for more examples and details on usage.

Bindings

Various binding possibilities include:

Bind to Hash object

Create target:

options = { input: STDIN, output: STDOUT }

Use OptionBinder directly:

OptionBinder.new(target: options) do
  # ...
end

Use ARGV shortcut:

ARGV.define_and_bind(to: options) do
  # ... 
end  

Bind to public accessors

Create target:

class Options
  attr_accessor :input, :output

  def initialize
    @input, @output = STDIN, STDOUT
  end
end

Use OptionBinder directly:

OptionBinder.new(target: options) do
  # ...
end

Use ARGV shortcut:

ARGV.define_and_bind(to: options) do
  # ... 
end  

Bind to class variables

Create target:

class Options
  @@input, @@output = STDIN, STDOUT
end

options = Options.new

Use OptionBinder directly:

OptionBinder.new(target: options, bind: :to_class_variables) do
  # ...
end

Use ARGV shortcut:

ARGV.define_and_bind(to: options, via: :class_variables) do
  # ... 
end  

Bind to instance variables

Create target:

class Options
  def initialize
    @input, @output = STDIN, STDOUT
  end
end

options = Options.new

Use OptionBinder directly:

OptionBinder.new(target: options, bind: :to_instance_variables) do
  # ...
end

Use ARGV shortcut:

ARGV.define_and_bind(to: options, via: :instance_variables) do
  # ... 
end  

Bind to local variables

Create target:

input, output = STDIN, STDOUT

Use OptionBinder directly:

OptionBinder.new(target: TOPLEVEL_BINDING, bind: :to_local_variables) do
  # ...
end

Use OptionBinder directly with top level binding object as target by default:

OptionBinder.new do
  # ...
end

Use ARGV shortcut:

ARGV.define_and_bind(to: TOPLEVEL_BINDING, via: :local_variables) do
  # ... 
end  

Use ARGV shortcut with top level binding object as target by default:

ARGV.define_and_bind(to: :locals) do
  # ... 
end  

Testing

bundle exec rspec

Contributing

1. Fork it
2. Create your feature branch (git checkout -b new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin new-feature)
5. Create new Pull Request

License

This software is released under the MIT License