hw2 works

.gitignore

@@ -0,0 +1 @@
+*.swp

homework2/part1.rb

@@ -23,7 +23,7 @@
 # metaprogramming to the rescue!
 
 class Numeric
-  @@currencies = {'dollar' => 1, 'yen' => 0.013, 'euro' => 1.292, 'rupee' => 0.019}
+  @@currencies = { 'dollar' => 1, 'yen' => 0.013, 'euro' => 1.292, 'rupee' => 0.019 }
   def method_missing(name)
     convert(name, true) or super
   end
@@ -33,12 +33,22 @@ def in(name)
   end
 
   def convert(name, direct)
-    if direct
-      operation = :*
-    else
-      operation = :/
-    end
+    operation = direct ?  :* : :/
     singular_currency = name.to_s.gsub( /s$/, '')
     @@currencies.has_key?(singular_currency) && send(operation, @@currencies[singular_currency])
   end
 end
+
+class String
+  def palindrome?
+    backstring = downcase.gsub /\W/, ''
+    backstring == backstring.reverse
+  end
+end
+
+module Enumerable
+  def palindrome?
+    pair = self.inject([[],[]]) { |acc, el| [acc.first + [el], [el] + acc.last] }
+    pair.first == pair.last
+  end
+end

homework2/part2.rb

@@ -15,10 +15,11 @@
   #Cartesian product b×a.)
   #To start you off, here is a code skeleton and some examples showing possible correct results.
 
-
 class CartesianProduct
+  include Enumerable
+
   def initialize(*args)
-    @product = cartesian args
+    @product = cartesian(args)
   end
 
   def each
@@ -27,7 +28,7 @@ def each
 
 private
 
-  def cartesian arrays
+  def cartesian(arrays)
     case arrays.length
     when 0
       []
@@ -40,8 +41,8 @@ def cartesian arrays
     end
   end
 
-  def trivial_cartesian arrays
+  def trivial_cartesian(arrays)
     lhs, rhs = *arrays
-    lhs.inject([]) { |acc, i| acc + ([i] * rhs.length).zip(rhs)}
+    lhs.inject([]) { |acc, i| acc + ([i] * rhs.length).zip(rhs) }
   end
 end