hamster_v_clojure.rb

require 'benchmark'
require 'hamster'
require 'deps/clojure-1.4.0.jar'

Benchmark.bm do |bm|
  def fill(hash)
    (0..10000).reduce(hash) do |h, i|
      if h.class == Java::ClojureLang::PersistentHashMap
        h.assoc(i, 1)
      elsif h.respond_to?(:put)
        h.put(i, 1)
      else
        h[i] = 1
        h
      end
    end
  end

  ruby_hash =    fill(Hash.new)
  hamster_hash = fill(Hamster.hash())
  clojure_hash = fill(Java::ClojureLang::PersistentHashMap::EMPTY)

  bm.report("                                    ::Hash with native select") {
    ruby_hash.select { |k, _| k.odd? }
  }

  bm.report("                             Hamster::Hash with native select") {
    hamster_hash.select { |k, _| k.odd? }
  }

  bm.report("      Java::ClojureLang::PersistentHashMap with native select") {
    clojure_hash.select { |k, _| k.odd? }
  }

  bm.report("                              ::Hash with reduce-based select") {
    ruby_hash.reduce(Hash.new) { |h, (k, v)| h[k] = v if k.odd?; h }
  }

  bm.report("                       Hamster::Hash with reduce-based select") {
    hamster_hash.reduce(Hash.new) { |h, (k, v)| h[k] = v if k.odd?; h }
  }

  bm.report("Java::ClojureLang::PersistentHashMap with reduce-based select") {
    clojure_hash.reduce(Hash.new) { |h, (k, v)| h[k] = v if k.odd?; h }
  }
end