gistfile1.rb

require 'benchmark'
require 'strscan'

n = 100000

u = "hello_world/whatever"

class String
  # From rails
  def camelize
    self.gsub(/\/(.?)/) { "::" + $1.upcase }.gsub(/(^|_)(.)/) { $2.upcase }
  end

  # From merb
  def mamelize
    new_string = ""
    input = StringScanner.new(self.downcase)
    until input.eos?
      if input.scan(/([a-z][a-zA-Z\d]*)(_|$|\/)/)
        new_string << input[1].capitalize
        new_string << "::" if input[2] == '/'
      end
    end
    new_string
  end

  def lamelize
    self.split('/').map { |ss| ss.split('_').map { |sub| sub.capitalize }.join }.join('::')
  end

  def damelize
    self.gsub(/\/(.?)/) { "::#{$1.upcase}" }.gsub(/(?:^|_)(.)/) { $1.upcase }
  end
end

puts u.camelize
puts u.mamelize
puts u.lamelize
puts u.damelize

Benchmark.bm do |x|
  x.report("Camelize") do 
    n.times { u.camelize }
  end

  x.report("Mamelize") do
    n.times { u.mamelize } 
  end

  x.report("Lamelize") do
    n.times { u.mamelize } 
  end

  x.report("Damelize") do
    n.times { u.damelize } 
  end
end