class Rails::SourceAnnotationExtractor

def find_in(dir)

taken into account. Only files with annotations are included.
Rails::SourceAnnotationExtractor::Annotation.extensions are
with their annotations. Files with extensions registered in
Returns a hash that maps filenames under +dir+ (recursively) to arrays 
def find_in(dir)
  results = {}
  Dir.glob("#{dir}/*") do |item|
    next if File.basename(item).start_with?(".")
    if File.directory?(item)
      results.update(find_in(item))
    else
      extension = Annotation.extensions.detect do |regexp, _block|
        regexp.match(item)
      end
      if extension
        pattern = extension.last.call(tag)
        results.update(extract_annotations_from(item, pattern)) if pattern
      end
    end
  end
  results
end