rake_default_task.rb

def default_task(deps=nil, &block)
  create_default_task(false, deps, &block)
end

def default_multitask(deps=nil, &block)
  create_default_task(true, deps, &block)
end

def create_default_task(multitask, deps=nil, &block)

  # Save the description
  description = Rake.application.last_description
  Rake.application.last_description = nil

  # Define the default task within the namespace
  task_call = multitask ? :multitask : :task
  if deps.is_a? Hash
    self.send(task_call, :default, deps, &block)
  else
    if deps
      self.send(task_call, :default => deps, &block)
    else
      self.send(task_call, :default, &block)
    end
  end

  # Save the current scope
  current_scope = Rake.application.instance_variable_get("@scope")

  # Get the task_name from the scope
  scope_path = current_scope.to_a
  task_name = scope_path.shift

  # Create a scope to imitate the parent scope
  parent_scope = Rake::Scope.make(*scope_path)
  Rake.application.instance_variable_set("@scope", parent_scope)

  # Define the task
  desc description
  if deps.is_a? Hash
    task task_name, deps.keys.first => current_scope.path_with_task_name("default")
  else
    task task_name => current_scope.path_with_task_name("default")
  end

  # Reset the scope back to what it was
  Rake.application.instance_variable_set("@scope", current_scope)
end