Easy syntax for defining helpers

[denisdefreyne]

Helpers are currently defined as modules that can be included:

module MyHelper
  def something
    # …
  end
end

use_helper MyHelper

This approach has some problems:

• no memoization possible
• no private methods possible

While it’s possible to work around these limitations (e.g. like this: https://gist.github.com/ddfreyne/b4c9df905a2bb927fd888d64183fda7f), it would be nice to have a built-in way to define helpers in Nanoc that avoids these issues. For example:

class MyHelper < Nanoc::Helper
  memoized def something
    # …
  end

  private def secret_method_omg
    # …
  end
end

use_helper MyHelper