class ERB::Compiler

def detect_magic_comment(s, enc = nil)
  re = @percent ? /\G(?:<%#(.*)%>|%#(.*)\n)/ : /\G<%#(.*)%>/
  frozen = nil
  s.scan(re) do
    comment = $+
    comment = $1 if comment[/-\*-\s*([^\s].*?)\s*-\*-$/]
    case comment
    when %r"coding\s*[=:]\s*([[:alnum:]\-_]+)"
      enc = Encoding.find($1.sub(/-(?:mac|dos|unix)/i, ''))
    when %r"frozen[-_]string[-_]literal\s*:\s*([[:alnum:]]+)"
      frozen = $1
    end
  end
  return enc, frozen
end