class GitHub::Markup::Implementation

def file_ext_regexp
  @file_ext_regexp ||= /\.(#{regexp})\z/
end

def initialize(regexp, languages)
  @regexp = regexp
  if defined?(::Linguist)
    @languages = languages.map do |l|
      lang = Linguist::Language[l]
      raise "no match for language #{l.inspect}" if lang.nil?
      lang
    end
  end
end

def load
  # no-op by default
end

def match?(filename, language)
  if defined?(::Linguist)
    languages.include? language
  else
    file_ext_regexp =~ filename
  end
end

def render(filename, content, options: {})
  raise NotImplementedError, "subclasses of GitHub::Markup::Implementation must define #render"
end