class Byebug::SourceFileFormatter

def lines(min, max)
  File.foreach(file).with_index.map do |line, lineno|
    next unless (min..max).cover?(lineno + 1)
    format(
      "%<annotation>s %<lineno>#{max.to_s.size}d: %<source>s",
      annotation: annotator.call(lineno + 1),
      lineno: lineno + 1,
      source: line
    )
  end
end