gem-hunter

User friendly CLI apps for Elixir.

Here is a small screencast of what a generated CLI app looks like.

Add ex_cli to your list of dependencies in mix.exs:

def deps do
  [{:ex_cli, "~> 0.1.0"}]
end

The basic usage is to use ExCLI.DSL to define your CLI, and ExCLI.run to run it. Here is a sample application:

defmodule MyApp.SampleCLI do
  use ExCLI.DSL

  name "mycli"
  description "My CLI"
  long_description ~s"""
  This is my long description
  """

  option :verbose, count: true, aliases: [:v]

  command :hello do
    aliases [:hi]
    description "Greets the user"
    long_description """
    Gives a nice a warm greeting to whoever would listen
    """

    argument :name
    option :from, help: "the sender of hello"

    run context do
      if context.verbose > 0 do
        IO.puts("Running hello command")
      end
      if from = context[:from] do
        IO.write("#{from} says: ")
      end
      IO.puts("Hello #{context.name}!")
    end
  end
end

ExCLI.run!(MyApp.SampleCLI)

Which can be used in the following way.

sample_cli hello -vv world --from me

or using the command's alias:

sample_cli hi -vv world --from me

The application usage will be shown if the parsing fails. The above example would show:

usage: mycli [--verbose] <command> [<args>]

Commands
   hello   Greets the user

You can very easily generate a mix task or an escript using ExCLI

Pass escript: true to the use ExCLI.DSL and set the module as escript :main_module:

# lib/my_escript_cli.ex
defmodule MyEscriptCLI do
  use ExCLI.DSL, escript: true
end

# mix.exs
defmodule MyApp.Mixfile do
  def project do
    [app: :my_app,
     escript: [main_module: MyEscriptCLI]]
  end
end

Pass mix_task: TASK_NAME to the use ExCLI.DSL.

# lib/my_cli_task.ex
defmodule MyCLITask do
  use ExCLI.DSL, mix_task: :great_task
end

You can then run

mix great_task

and get nicely formatted help with

mix help great_task

Check out the documentation for more information.

• Command parser

  The command parser is now working and should be enough for a good number of tasks.

• Integration with escript and mix

  ExCLI.DSL can generate a module compatible with escript.build as well as a mix task.

• Usage generation

  A nicely formatted usage is generated from the DSL.

• Help command

  Then the goal will be to add a help command which can be used as app help command to show help about command.

• Command parser improvements

  When the usage and help parts are done, there are a few improvements that will be nice to have in the command parser:

  • the ability to set a default command
  • the ability to easily delegate a command to another module
  • command aliases

• Man page generation

  When all this is done, the last part will to generate documentation in man page and markdown formats, which will probably be done as a mix task.

Contributions are very welcome, feel free to open an issue or a PR.

I am also looking for a better name, ideas are welcome!