def print_error(error)
      $stderr.puts

      # Header
      $stderr.puts '+--- /!\ ERROR /!\ -------------------------------------------+'
      $stderr.puts '| An exception occured while compiling the site. If you think |'
      $stderr.puts '| this is a bug in nanoc, please do report it at              |'
      $stderr.puts '| <http://projects.stoneship.org/trac/nanoc/newticket> --     |'
      $stderr.puts '| thanks in advance!                                          |'
      $stderr.puts '+-------------------------------------------------------------+'

      # Exception
      $stderr.puts
      $stderr.puts '=== MESSAGE:'
      $stderr.puts
      $stderr.puts "#{error.class}: #{error.message}"

      # Compilation stack
      $stderr.puts
      $stderr.puts '=== COMPILATION STACK:'
      $stderr.puts
      if ((@base.site && @base.site.compiler.stack) || []).empty?
        $stderr.puts "  (empty)"
      else
        @base.site.compiler.stack.reverse.each do |obj|
          if obj.is_a?(Nanoc3::ItemRep)
            $stderr.puts "  - [item]   #{obj.item.identifier} (rep #{obj.name})"
          else # layout
            $stderr.puts "  - [layout] #{obj.identifier}"
          end
        end
      end

      # Backtrace
      require 'enumerator'
      $stderr.puts
      $stderr.puts '=== BACKTRACE:'
      $stderr.puts
      $stderr.puts error.backtrace.to_enum(:each_with_index).map { |item, index| "  #{index}. #{item}" }.join("\n")
    end