require 'benchmark'
include Benchmark

class A
  def foo(a, b, c)
    1
  end
end


class M1
  def method_missing(key, *args, &block)
    1
  end
end

class M2
  def method_missing(key, *args, &block)
    if(key == :foo)
      send :bar, args[0], args[1], args[2]
    end
  end

  def bar(a,b,c)
    1
  end

end

class M3
  def method_missing(key, *args, &block)
    if(key.to_s.index("foo"))
      send :bar, args[0], args[1], args[2]
    end
  end

  def bar(a,b,c)
    1
  end

end

class M4
  def method_missing(key, *args, &block)
    if(key.to_s =~ /foo/)
      send :bar, args[0], args[1], args[2]
    end
  end

  def bar(a,b,c)
    1
  end
end

class M5
  def method_missing(key, *args, &block)
    if(key.to_s =~ /foo/)
      self.class.class_eval <<-EOF, __FILE__, __LINE__
      def #{key}(a, b, c)
        bar a, b, c
      end
EOF
      send key, args[0], args[1], args[2]
    end
  end

  def bar(a,b,c)
    1
  end
end

class M6
  def method_missing(key, *args, &block)
    if(key.to_s =~ /foo/)
      self.class.class_eval <<-EOF, __FILE__, __LINE__
      def #{key}(a, b, c)
        1 # inlining the call
      end
EOF
      send key, args[0], args[1], args[2]
    end
  end

end


T = 1_000_000
a = A.new
m1 = M1.new
m2 = M2.new
m3 = M3.new
m4 = M4.new
m5 = M5.new
m6 = M6.new

Benchmark.bm(25) do |bm|
  bm.report("static method"){T.times{a.foo(1,2,3)}}
  bm.report("method missing baseline"){T.times{m1.foo(1,2,3)}}
  bm.report("symbol equality"){T.times{m2.foo(1,2,3)}}
  bm.report("index check"){T.times{m3.foo(1,2,3)}}
  bm.report("regular expression"){T.times{m4.foo(1,2,3)}}
  bm.report("caching of method missing"){T.times{m5.foo(1,2,3)}}
  bm.report("caching + inlining"){T.times{m6.foo(1,2,3)}}
end

# VERSION = 1.8.7-p72
#                                user     system      total        real
# static method              0.295612   0.001624   0.297236 (  0.321701)
# method missing baseline    0.567643   0.003783   0.571426 (  0.628578)
# symbol equality            1.139567   0.006818   1.146385 (  1.224589)
# index check                1.377338   0.008638   1.385976 (  1.498267)
# regular expression         1.837666   0.012901   1.850567 (  2.047866)
# caching of method missing  0.486595   0.002270   0.488865 (  0.511950)
# caching + inlining         0.365636   0.001684   0.367320 (  0.383320)
#
# VERSION = 1.9.0-5
#                                user     system      total        real
# static method              0.287593   0.001519   0.289112 (  0.308552)
# method missing baseline    0.552172   0.003834   0.556006 (  0.604434)
# symbol equality            1.180124   0.005763   1.185887 (  1.260123)
# index check                1.297773   0.007940   1.305713 (  1.415773)
# regular expression         1.858729   0.012671   1.871400 (  2.063151)
# caching of method missing  0.457304   0.002010   0.459314 (  0.478891)
# caching + inlining         0.342845   0.002021   0.344866 (  0.361926)
#
#  VERSION = JRUBY
#                                user     system      total        real
# static method              0.313397   0.002809   0.316206 (  0.354470)
# method missing baseline    0.570404   0.004562   0.574966 (  0.637837)
# symbol equality            1.082941   0.006078   1.089019 (  1.173902)
# index check                1.256466   0.008117   1.264583 (  1.395792)
# regular expression         1.627718   0.012748   1.640466 (  1.872134)
# caching of method missing  0.471655   0.002542   0.474197 (  0.501606)
# caching + inlining         0.362206   0.001912   0.364118 (  0.383157)
#
#   VERSION = rubinius 0.10.0 (362a70237)
#                                user     system      total        real
# static method              0.479927   0.000000   0.479927 (  0.479883)
# method missing baseline    1.024028   0.000000   1.024028 (  1.024081)
# symbol equality            1.485076   0.000000   1.485076 (  1.485110)
# index check               10.996608   0.000000  10.996608 ( 10.996657)
# regular expression         6.458455   0.000000   6.458455 (  6.458505)
# caching of method missing  0.636479   0.000000   0.636479 (  0.636501)
# caching + inlining       Segmentation fault
#
# It's interesting for me looking at different implementations and see how things
# differ from one another. It really shows places where they need improvements.