Roughly estimate usage of Enumerable methods

enumetric.rb

#! /usr/bin/env ruby
#
# enumetric.rb
# 
# Rough estimate of usage/non-usage of Enumerable methods

TRIVIAL_METHODS  = [:first, :count, :to_a]

def count_usage(method, dir = '.')
  method_delimiter = '[\s\.\{\(=]'
  method = method.to_s.sub('?','\?')
  cmd = "ack --no-group --ruby \"\\.#{method}#{method_delimiter}\" #{dir}"
  IO.popen(cmd).count
end

def measure_enumerable_usage(dir = '.')
  Enumerable.instance_methods.each_with_object({}) { |m, set|
    set[m] = count_usage(m, dir)
  }
end

def tally_enumetric(dir = '.')
  each_count = count_usage('each', dir)
  enumerable_usage = measure_enumerable_usage(dir)
  enumerable_count = enumerable_usage.values.reduce(&:+)
  most_common = enumerable_usage.max_by {|k,v| v}
  least_common = enumerable_usage.reject{|k,v| v.zero?}.min_by {|k,v| v}
  non_trivial = enumerable_usage.reject {|k,v| TRIVIAL_METHODS.member? k }
  ratio = 100.0 * each_count / (each_count + enumerable_count)
  non_trivial_ratio = 100.0  * each_count / (each_count + non_trivial.values.reduce(&:+))
  puts "#each count: #{each_count}"
  puts "Enumerable method usage: #{enumerable_count}"
  puts "Each ratio (lower is better): #{ratio.round(2)}%"
  puts "Non-trivial each ratio: #{non_trivial_ratio.round(2)}%"
  puts "Most Used: #{most_common[0]} / #{most_common[1]} times"
  puts "Least Used: #{least_common[0]} / #{least_common[1]} times"
  puts "Used once: #{enumerable_usage.select{|k,v| v == 1}.map{|k,v| k}}"
  puts "Never used: #{enumerable_usage.select{|k,v| v.zero?}.map{|k,v| k}}"
  puts "All usage: #{enumerable_usage.reject{|k,v| v.zero?}.sort_by {|k,v| v}.map{|k,v| "#{k}: #{v}"}}"
end

if __FILE__ == $0
  if dir = ARGV[0]
    tally_enumetric(dir)
  else
    tally_enumetric
  end
end