From: "Mauricio Fernández" <mfp@...>
Date: 2005-09-15T00:38:00+09:00
Subject: Re: Sets, uniqueness not unique.

On Wed, Sep 14, 2005 at 11:12:16PM +0900, Hugh Sasse wrote:
> +  def eql?(other)
> +    (self.class)::FIELDS.inject(true) do |b,v|
> +      begin
> +        b && (self.send(v) == other.send(v))
> +      rescue
> +        b = false
> +      end
> +    end
> +  end

Just one minor comment:

batsman@tux-chan:~$ cat /tmp/fdsfdsdsd.rb
class Foo
  FIELDS = %w[name stuff foo bar]
  attr_reader(*FIELDS)

  def initialize(name, stuff, foo, bar)
    @name, @stuff, @foo, @bar = name, stuff, foo, bar
  end

  def eql1?(other)
    (self.class)::FIELDS.inject(true) do |b,v|
      begin
        b && (self.send(v) == other.send(v))
      rescue
        b = false
      end
    end
  end

  def eql2?(other)
    # maybe add self.class::FIELDS == other.class::FIELDS test plus rescue NameError ?
    self.class::FIELDS.each{|m| break false if self.send(m) != other.send(m) } && true
  rescue NoMethodError
    false
  end
end

require 'benchmark'
a = Foo.new("a", "b", "c", "d")
b = Foo.new("e", "b", "c", "d")
c = Foo.new("a", "b", "c", "e")

TIMES = 100000
%w[a b c].each{|x| puts "#{x} = #{eval(x).inspect}"}
Benchmark.bmbm do |x|
  %w[a b c].each do |o|
    %w[eql1? eql2?].each do |m|
      s = "a.#{m}(#{o})"
      x.report("#{s}: #{eval(s)}") { eval("TIMES.times{#{s}}") }
    end
  end
end
batsman@tux-chan:~$ ruby -v /tmp/fdsfdsdsd.rb
ruby 1.8.3 (2005-05-22) [i686-linux]
a = #<Foo:0xb7dc9c98 @name="a", @bar="d", @foo="c", @stuff="b">
b = #<Foo:0xb7dc9c20 @name="e", @bar="d", @foo="c", @stuff="b">
c = #<Foo:0xb7dc9ba8 @name="a", @bar="e", @foo="c", @stuff="b">
Rehearsal -----------------------------------------------------
a.eql1?(a): true    1.520000   0.000000   1.520000 (  1.658224)
a.eql2?(a): true    0.880000   0.000000   0.880000 (  0.970675)
a.eql1?(b): false   1.070000   0.000000   1.070000 (  1.156081)
a.eql2?(b): false   0.360000   0.010000   0.370000 (  0.410011)
a.eql1?(c): false   1.570000   0.000000   1.570000 (  1.734145)
a.eql2?(c): false   0.910000   0.000000   0.910000 (  1.003833)
-------------------------------------------- total: 6.320000sec

                        user     system      total        real
a.eql1?(a): true    1.510000   0.010000   1.520000 (  1.679369)
a.eql2?(a): true    0.890000   0.000000   0.890000 (  0.950153)
a.eql1?(b): false   1.100000   0.010000   1.110000 (  1.200057)
a.eql2?(b): false   0.360000   0.000000   0.360000 (  0.383755)
a.eql1?(c): false   1.560000   0.010000   1.570000 (  1.739114)
a.eql2?(c): false   0.920000   0.000000   0.920000 (  0.978109)

-- 
Mauricio Fernandez