class Rouge::Guessers::Modeline

def filter(lexers)
  # don't bother reading the stream if we've already decided
  return lexers if lexers.size == 1
  source_text = get_source(@source)
  lines = source_text.split(/\n/)
  search_space = (lines.first(@lines) + lines.last(@lines)).join("\n")
  matches = MODELINES.map { |re| re.match(search_space) }.compact
  return lexers unless matches.any?
  match_set = Set.new(matches.map { |m| m[1] })
  lexers.select { |l| match_set.include?(l.tag) || l.aliases.any? { |a| match_set.include?(a) } }
end

def initialize(source, opts={})
  @source = source
  @lines = opts[:lines] || 5
end