argparser

Yet another ruby command line argument parser library.

Installation

gem install argparser as usual.

Usage by example

Suppose there's a file named example.rb like this:

require 'argparser'
args= ArgParser.new( # Here goes the manifest.
  :program => 'example.rb', # Use additional properties like these:
  :version => '1.0',        #   :info, :copyright, :license,
  :options => [{            #   :package, :bugs, :homepage
    :names      => %w[mode m],
    :param      => 'first|second|third',
    :default    => 'first',
    :multiple   => true,
    :help       => 'Example mode.',
    :validate   => (lambda {|this, parser|  # Validating value in-line
      possible = this.argument.split('|')
      this.value.select{|v| possible.include?(v)}.size == this.value.size })
  }],
  :arguments => [{
    :name       => 'file',
    :required   => true,
    :help       => 'Filename or - for stdin.',
    :validate   => (lambda {|this, parser|
      if this.value == '-'
        this.reset.set_value($stdin.read)
      else
        parser.terminate(2, 'No such file') unless File.exists?(this.value)
        this.reset.set_value(File.read(this.value))
      end })
  }]
).parse   # Uses ARGV by default, you may supply your own arguments.
          # It exits if bad arguments given or they aren't validated.

puts args['mode'].value.inspect # So we could use our options...
puts args['file'].value         # Prints contents of a file

This file located here: lib/argparser/examples/example.rb.

Now, let's look at the output of example given in various cases.

$ ruby example.rb is unsufficient:

example.rb [-m, --mode first|second|third]... file
Expected argument: file

$ ruby example.rb --help helps:

example.rb [-m, --mode first|second|third]... file
[-m, --mode first|second|third]...
  Example mode.
[--help]
  Print this help and exit.
[--version]
  Print version and exit.
file
  Filename or - for stdin.

$ echo "content" | ruby example.rb - does the trick:

["first"]
content

$ echo "content" | ruby example.rb --mode fourth - oopses:

example.rb [-m, --mode first|second|third]... file
Invalid option: m

$ echo "content" | ruby example.rb -abcm first -:

example.rb [-m, --mode first|second|third]... file
Unknown option: a

Consider more rules

• --help and --version options provided unless specified explicitly
• printed synopsis provided unless specified explicitly
• :default setting assigns default option's value if value isn't specified
• -- argument honored
• ArgParser#parse supports block(option_name, option_value) to read options/arguments supplied

Tests

bundle exec rake test

Documentation

This README is all i could say in a rush. No other documentation provided at this moment, see the sources.

If you've found a bug or drawback

Don't hesistate to leave a report.

License

MIT for now.