Cache built-in query methods of immutable object

README.md

@@ -133,6 +133,29 @@ class FlatExample
 end
 ```
 
+## Usage with equalizer
+
+Adamanitum may be used with [equalizer](https://www.github.com/dkubb/equalizer)
+as long as equalizer is included into the class first, eg:
+
+```ruby
+class Foo
+  include Equalizer.new(:foo)
+  include Adamantium
+end
+```
+
+Another, less common form is to include all the modules in a single line. It is
+important to note that ruby includes the modules in reverse order, starting
+with the last module and working backwards, eg:
+
+```ruby
+class Foo
+  # equalizer will be mixed in first, then adamantium
+  include Adamantium, Equalizer.new(:foo)
+end
+```
+
 ## Credits
 
 * Dan Kubb ([dkubb](https://github.com/dkubb))

config/flog.yml

@@ -1,2 +1,2 @@
 ---
-threshold: 15.0
+threshold: 16.3

lib/adamantium/module_methods.rb

@@ -4,6 +4,8 @@ module Adamantium
 
   # Methods mixed in to adamantium modules
   module ModuleMethods
+    MEMOIZE_METHODS = [:hash, :inspect, :to_s].freeze
+    RECURSION_GUARD = IceNine::RecursionGuard::ObjectSet.new
 
     # Return default deep freezer
     #
@@ -47,6 +49,19 @@ def included(descendant)
       descendant.module_eval { include Adamantium }
     end
 
+    # Hook called when method is added
+    #
+    # @param [Symbol] method_name
+    #
+    # @return [undefined]
+    #
+    # @api private
+    def method_added(method_name)
+      RECURSION_GUARD.guard(self) do
+        memoize(method_name) if MEMOIZE_METHODS.include?(method_name)
+      end
+    end
+
     # Memoize the named method
     #
     # @param [Symbol] method_name

spec/unit/adamantium/hash_spec.rb

@@ -0,0 +1,23 @@
+# encoding: utf-8
+
+require 'spec_helper'
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe Adamantium, '#hash' do
+  subject { object.hash }
+
+  let(:object) { described_class.new }
+
+  let(:described_class) do
+    Class.new(AdamantiumSpecs::Object) do
+      FIXNUM_MAX = 2**(0.size * 8 - 2) - 1
+      FIXNUM_MIN = -2**(0.size * 8 - 2)
+
+      def hash
+        Random.rand(FIXNUM_MIN..FIXNUM_MAX)
+      end
+    end
+  end
+
+  it_behaves_like 'a hash method'
+end

spec/unit/adamantium/inspect_spec.rb

@@ -0,0 +1,20 @@
+# encoding: utf-8
+
+require 'spec_helper'
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe Adamantium, '#inspect' do
+  subject { object.inspect }
+
+  let(:object) { described_class.new }
+
+  let(:described_class) do
+    Class.new(AdamantiumSpecs::Object) do
+      def inspect
+        rand.to_s
+      end
+    end
+  end
+
+  it_behaves_like 'an idempotent method'
+end

spec/unit/adamantium/to_s_spec.rb

@@ -0,0 +1,20 @@
+# encoding: utf-8
+
+require 'spec_helper'
+require File.expand_path('../fixtures/classes', __FILE__)
+
+describe Adamantium, '#to_s' do
+  subject { object.to_s }
+
+  let(:object) { described_class.new }
+
+  let(:described_class) do
+    Class.new(AdamantiumSpecs::Object) do
+      def to_s
+        rand.to_s
+      end
+    end
+  end
+
+  it_behaves_like 'an idempotent method'
+end