calculate_directory_statistics

# File railties/lib/rails/code_statistics.rb, line 29
    def calculate_directory_statistics(directory, pattern = /.*\.rb$/)
      stats = { "lines" => 0, "codelines" => 0, "classes" => 0, "methods" => 0 }

      Dir.foreach(directory) do |file_name|
        if File.stat(directory + "/" + file_name).directory? and (/^\./ !~ file_name)
          newstats = calculate_directory_statistics(directory + "/" + file_name, pattern)
          stats.each { |k, v| stats[k] += newstats[k] }
        end

        next unless file_name =~ pattern

        f = File.open(directory + "/" + file_name)

        while line = f.gets
          stats["lines"]     += 1
          stats["classes"]   += 1 if line =~ /class [A-Z]/
          stats["methods"]   += 1 if line =~ /def [a-z]/
          stats["codelines"] += 1 unless line =~ /^\s*$/ || line =~ /^\s*#/
        end
      end

      stats
    end