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clap

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Command line argument parsing

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Clap
====

Command line argument parsing for simple applications.

Description
-----------

Clap is a small library that can be bundled with your command line
application. It covers the simple case of executing code based on the
flags or parameters passed.

Usage
-----

Using Clap is simple: just pass `ARGV` and a hash of flags, and it
will extract the arguments as needed.

``` ruby
Clap.run ARGV,
  "-a" => lambda { |param| ... },
  "-b" => lambda { ... }
```

To better illustrate the usage, in the following examples `ARGV` is
replaced by an array of strings.

If you want your command line application to require a file or display
a version number, you can configure it like this:

``` ruby
Clap.run %w(-r foo -v),
  "-r" => lambda { |file| require file },
  "-v" => lambda { puts VERSION }
```

This will detect the `-r` or `-v` flags and act accordingly. Note that
it will also read the necessary number of parameters for each flag
based on the arity of the passed lambda.

Another example, for an application that takes a `-v` flag and also a
list of files:

``` ruby
files = Clap.run %w(-v foo bar),
  "-v" => lambda { puts VERSION }

files == %w(foo bar)
```

Using methods instead of lambdas
--------------------------------

If you prefer to group the options in a module or class, you can still
attach the methods to command line flags:

``` ruby
class MyApp
  module CLI
    def self.version
      puts VERSION
    end

def self.help(command)
      puts HELP[command]
    end
  end
end

Clap.run %w(-v -h foo),
  "-v" => MyApp::CLI.method(:version),
  "-h" => MyApp::CLI.method(:help)
```

When in doubt, check the tests for the different use cases.

Installation
------------

$ gem install clap

License
-------

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

clap

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