Handling Events

A callback is a Proc object to be invoked when an event occur. The callback feature is provided by the Callback library. For more information about the library, see README.

Crystal CLI provides the following events:

• initialize: occurs when a command is initialized.
• exit: occurs when a command ends or exits. A callback receives a Cli::Exit object.

class FinallySmile < Cli::Command
  after_exit do |cmd, exit|
    cmd.puts exit.message
    cmd.puts ":)"
  end

  def run
    exit! ":("
  end
end

FinallySmile.run

Output:

:(
:(
:)