module Middleman::CoreExtensions::Extensions::ClassMethods

def configure(env, &block)
  send("#{env}_config", &block)
end

def register(extension, options={}, &block)
  if extension.instance_of?(Class) && extension.ancestors.include?(::Middleman::Extension)
    extension.new(self, options, &block)
  else
    extend extension
    if extension.respond_to?(:registered)
      if extension.method(:registered).arity == 1
        extension.registered(self, &block)
      else
        extension.registered(self, options, &block)
      end
    end
    extension
  end
end