Report leading whitespace in a set of files to characterize programmers' indentation conventions.

gistfile1.rb

class Array
  def freq_by &block
    group_by(&block).map {|k,v| [k, v.count] }.sort_by(&:first)
  end

  def freq
    freq_by {|e| e }
  end
end

puts ARGF.lines.map {|l| l.split(/\S/).first }
               .compact
               .freq
               .sort_by {|p,c| -c }
               .map {|p,c| "%5d %2d: %s" % [c, p.length, p.dump] }
               .join($/)