Normalize indents within heredocs so your code stays pretty

normalize_heredoc.rb

module NormalizeHeredoc
  module_function
  # Normalize indents, like for heredoc strings
  def NormalizeIndent( msg )
    msg = String(msg)
    depth = msg.scan(/^\s*/).flatten.map(&:size).min
    msg.gsub(/^\s{#{depth}}/, '')
  end
end

module Deep
  class Nesting
    include NormalizeHeredoc
    def demo
      puts NormalizeIndent(<<-END)
        Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer 
        nec odio. Praesent libero. Sed cursus ante dapibus diam. Sed nisi.
        Nulla quis sem at nibh elementum imperdiet. Duis sagittis ipsum.
        
            This block's indent relative to the rest of the message will be
            preserved.
            
               This one too.
        
        That is all.
      END
    end
  end
end

Deep::Nesting.new.demo