gistfile1.rb

require 'active_support/inflector'
require 'benchmark'

# QUICK HACK
class RuleSet
  def initialize
    @rules      = []
    @regexp     = nil
    @group2rule = {}
  end

  def append_rule(pattern, replacement)
    ngroups = @regexp ? count_groups(@regexp) : 0
    @group2rule[ngroups] = @rules.size

    new_regexp = build_regexp(pattern)
    @regexp = @regexp ? Regexp.union(@regexp, new_regexp) : new_regexp

    @rules << [pattern, replacement]
  end

  def build_regexp(pattern)
    pattern = Regexp.quote(pattern) if pattern.is_a?(String)
    /(#{pattern})/
  end

  def apply(word)
    word = word.dup
    if md = @regexp.match(word)
      index = md.captures.find_index {|_| _}
      rule  = @rules[@group2rule[index]]
      word.sub!(rule[0], rule[1])
    end
    word
  end

  def count_groups(pattern)
    Regexp.union(pattern, //).match('').captures.length
  end
end

rs = RuleSet.new
ActiveSupport::Inflector::Inflections.instance.plurals.each do |pattern, replacement|
  rs.append_rule(pattern, replacement)
end

words = File.readlines('/usr/share/dict/words').map(&:chomp)

STDOUT.sync = true
print "sanity checking... %00"
words.each_with_index do |word, i|
  print "\b\b%02d" % ((100.0*i)/words.size).to_i if i % 1000 == 0
  unless ActiveSupport::Inflector::Inflections.instance.uncountables.include?(word)
    as_plural = ActiveSupport::Inflector.pluralize(word)
    rs_plural = rs.apply(word)
    raise "error: #{as_plural} vs #{rs_plural} for #{word}" unless as_plural == rs_plural
  end
end
puts "\b\b100\n"

Benchmark.bm do |x|
  x.report('AS') { words.each {|word| ActiveSupport::Inflector.pluralize(word) }}
  x.report('RS') { words.each {|word| rs.apply(word) }}
end

__END__
sanity checking... %100
       user     system      total        real
AS 75.010000   0.930000  75.940000 ( 78.532994)
RS 11.820000   0.160000  11.980000 ( 12.080551)