Implement respond_to? in module Monad (Fresh one)

.travis.yml

@@ -5,3 +5,5 @@ rvm:
   - 2.0.0
   - 2.1.2
 script: bundle exec rspec
+before_install:
+  - gem install bundler

lib/monads/eventually.rb

@@ -1,11 +1,12 @@
 require 'monads/monad'
 
 module Monads
-  Eventually = Struct.new(:block) do
+  class Eventually
     include Monad
+    attr_reader :block
 
     def initialize(&block)
-      super(block)
+      @block = block
     end
 
     def run(&success)

lib/monads/many.rb

@@ -1,8 +1,13 @@
 require 'monads/monad'
 
 module Monads
-  Many = Struct.new(:values) do
+  class Many
     include Monad
+    attr_reader :values
+
+    def initialize(values)
+      @values = values
+    end
 
     def and_then(&block)
       block = ensure_monadic_result(&block)

lib/monads/monad.rb

@@ -12,6 +12,12 @@ def method_missing(*args, &block)
       end
     end
 
+    def respond_to_missing?(method_name, include_private=false)
+      within do |value|
+        value.respond_to?(method_name, include_private)
+      end || super
+    end
+
     private
 
     def ensure_monadic_result(&block)

lib/monads/optional.rb

@@ -1,8 +1,13 @@
 require 'monads/monad'
 
 module Monads
-  Optional = Struct.new(:value) do
+  class Optional
     include Monad
+    attr_reader :value
+
+    def initialize(value)
+      @value = value
+    end
 
     def and_then(&block)
       block = ensure_monadic_result(&block)

spec/monads/eventually_spec.rb

@@ -102,13 +102,26 @@ module Monads
       it 'forwards any unrecognised message to the block’s value' do
         expect(value).to receive(:challenge)
         Eventually.new { |success| success.call(value) }.challenge.run {}
+        expect { Eventually.new { |success| success.call(value) }.method(:challenge) }.not_to raise_error
+        expect(Eventually.new { |success| success.call(value) }).to respond_to(:challenge)
       end
 
       it 'returns the message’s result wrapped in an Eventually' do
         @result = nil
         Eventually.new { |success| success.call(value) }.challenge.run { |result| @result = result }
         expect(@result).to eq response
       end
+
+      context 'when value is Enumerable' do
+        let(:value) { [1, 2, 3] }
+
+        it 'forwards any unrecognised message to the value' do
+          expect(Eventually.new { |success| success.call(value) }.first).to be_a(Eventually)
+          expect(Eventually.new { |success| success.call(value) }.first.run { |value| value }).to eq 1
+          expect(Eventually.new { |success| success.call(value) }.last).to be_a(Eventually)
+          expect(Eventually.new { |success| success.call(value) }.last.run { |value| value }).to eq 3
+        end
+      end
     end
   end
 end

spec/monads/many_spec.rb

@@ -87,11 +87,24 @@ module Monads
           expect(value).to receive(:challenge)
         end
         many.challenge
+        expect { many.method(:challenge) }.not_to raise_error
+        expect(many).to respond_to(:challenge)
       end
 
       it 'returns the messages’ results wrapped in a Many' do
         expect(many.challenge.values).to eq responses
       end
+
+      context 'when values are Enumerable' do
+        let(:values) { [[1, 2], [3, 5]] }
+
+        it 'forwards any unrecognised message to the value' do
+          expect(many.first).to be_a(Many)
+          expect(many.first.values).to eq [1, 3]
+          expect(many.last).to be_a(Many)
+          expect(many.last.values).to eq [2, 5]
+        end
+      end
     end
   end
 end

spec/monads/optional_spec.rb

@@ -89,11 +89,24 @@ module Monads
       it 'forwards any unrecognised message to the value' do
         expect(value).to receive(:challenge)
         optional.challenge
+        expect { optional.method(:challenge) }.not_to raise_error
+        expect(optional).to respond_to(:challenge)
       end
 
       it 'returns the message’s result wrapped in an Optional' do
         expect(optional.challenge.value).to eq response
       end
+
+      context 'when value is Enumerable' do
+        let(:value) { [1, 2, 3] }
+
+        it 'forwards any unrecognised message to the value' do
+          expect(optional.first).to be_a(Optional)
+          expect(optional.first.value).to eq 1
+          expect(optional.last).to be_a(Optional)
+          expect(optional.last.value).to eq 3
+        end
+      end
     end
   end
 end