class Haml::Exec::Generic

def handle_load_error(err)
  dep = err.message[/^no such file to load -- (.*)/, 1]
  raise err if @options[:trace] || dep.nil? || dep.empty?
  $stderr.puts <<MESSAGE
ed dependency #{dep} not found!
n "gem install #{dep}" to get it.
--trace for backtrace.
E
  exit 1
end