Benchmarking Data & Functional Implementations of List

Benchmarking Data & Functional Implementations of List

#This is the code underneath the blog post:
#http://stevechanin.blogspot.com/2010/09/benchmarking-functional-vs-data-based.html

List = Struct.new(:head, :tail)
Cons = ->(h,t) { List.new(h,t) }
Car = ->(list) { list.head }
Cdr = ->(list) { list.tail }

#[1, [2, 3], 4, 5]
lst = Cons.(1, Cons.(Cons.(2, Cons.(3, nil)), Cons.(4, Cons.(5,nil))))
raise "Problem with Car and Cdr" unless  Car.(Cdr.(Cdr.(l)))  == 4

f_Cons = ->(h,t) { ->(s) { (s==:h) ? h : t } } 
f_Car = ->(list) { list.(:h) } 
f_Cdr = ->(list) { list.(:t) }

f_lst = f_Cons.(1, f_Cons.(f_Cons.(2, f_Cons.(3, nil)), f_Cons.(4, f_Cons.(5,nil))))
raise "Problem with f_Car and f_Cdr" unless  f_Car.(f_Cdr.(f_Cdr.(f_lst)))  == 4

class List2
  attr_reader :car, :cdr

  def initialize(car, cdr)
    @car = car
    @cdr = cdr
  end

  def self.Cons(car, cdr)
    List2.new(car, cdr)
  end
end

c_lst = List2.Cons(1, List2.Cons(List2.Cons(2, List2.Cons(3, nil)), List2.Cons(4, List2.Cons(5,nil))))
raise "Problem with List2.car and List2.cdr" unless  c_lst.cdr.cdr.car

require 'benchmark'
c = 100_000
n = 5_000_000
#this benchmarks creates and extracting the "4" from (1, (2, 3), 4, 5)
Benchmark.bm do |rpt|
  rpt.report("List Create")  { c.times do; Cons.(1, Cons.(Cons.(2, Cons.(3, nil)), Cons.(4, Cons.(5,nil)))); end;}
  rpt.report("List Extract") { n.times do; Car.(Cdr.(Cdr.(lst))); end;}
  rpt.report("Func Create")  { c.times do; f_Cons.(1, f_Cons.(f_Cons.(2, f_Cons.(3, nil)), f_Cons.(4, f_Cons.(5,nil)))); end;}
  rpt.report("Func Extract")   { n.times do; f_Car.(f_Cdr.(f_Cdr.(f_lst))); end;}
  rpt.report("Class Create")  { c.times do; List2.Cons(1, List2.Cons(List2.Cons(2, List2.Cons(3, nil)), List2.Cons(4, List2.Cons(5,nil)))); end;}
  rpt.report("Class Extract")   { n.times do; c_lst.cdr.cdr.car; end;}
end