# File lib/sup/modes/edit-message-mode.rb, line 253
  def parse_file fn
    File.open(fn) do |f|
      header = Source.parse_raw_email_header(f).inject({}) { |h, (k, v)| h[k.capitalize] = v; h } # lousy HACK
      body = f.readlines.map { |l| l.chomp }

      header.delete_if { |k, v| NON_EDITABLE_HEADERS.member? k }
      header.each { |k, v| header[k] = parse_header k, v }

      [header, body]
    end
  end