Try out NullObject pattern.

lib/marky_markov.rb

@@ -4,12 +4,12 @@
 require_relative 'marky_markov/persistent_dictionary'
 require_relative 'marky_markov/markov_sentence_generator'
 
-# @version = 0.3.0
+# @version = 0.3.1
 # @author Matt Furden
 # Module containing TemporaryDictionary and Dictionary for creation of
 # Markov Chain Dictionaries and generating sentences from those dictionaries.
 module MarkyMarkov
-  VERSION = '0.3.0'
+  VERSION = '0.3.1'
 
   class TemporaryDictionary
     # Create a new Temporary Markov Chain Dictionary and sentence generator for use.

lib/marky_markov/markov_sentence_generator.rb

@@ -1,3 +1,15 @@
+# Messing about with the NullObject pattern, can't apply it in too many
+# places in this one. Need to evaluate what else could be used in this
+# aside from my first instinct of defaulting to []
+class NullObject
+  def method_missing (*args, &block)
+    self
+  end
+  def nil?; true; end
+  def <<(*); end
+end
+NULL_OBJECT = NullObject.new
+
 # @private
 class MarkovSentenceGenerator
   def initialize(dictionary)
@@ -12,36 +24,34 @@ def initialize(dictionary)
   #
   # @return [String] a string containing a random dictionary key.
   def random_word
-    keys = @dictionary.dictionary.keys
-    keys[rand(keys.length)]
+    words = @dictionary.dictionary.keys
+    words[rand(words.length)]
   end
 
   # Generates a random capitalized word via picking a random key from the
   # dictionary and recurring if the word is lowercase.
   #
   # (see #random_word)
-  def random_capitalized_word(attempts=0)
-    keys = @dictionary.dictionary.keys
-    x = keys[rand(keys.length)]
-    if /[A-Z]/ =~ x[0]
-      return x
-    elsif attempts < 30
-      # If you don't find a capitalized word after 30 attempts, just use
-      # a lowercase word as there may be no capitals in the dicationary.
-      random_capitalized_word(attempts+1)
-    else
-      random_word
+  def random_capitalized_word
+    attempts = 0
+    # If you don't find a capitalized word after 30 attempts, just use
+    # a lowercase word as there may be no capitals in the dicationary.
+    until attempts > 30
+      words = @dictionary.dictionary.keys
+      random_choice = words[rand(words.length)]
+      if /[A-Z]/ =~ random_choice[0]
+        return random_choice
+      end
     end
+    random_word
   end
 
   # Returns a word based upon the likelyhood of it appearing after the supplied word.
-  # 
+  #
   def weighted_random(lastword)
     # If word has no words in its dictionary (last word in source text file)
     # have it pick a random word to display instead.
-    if word = @dictionary.dictionary[lastword]
-      word.sample
-    end
+    @dictionary.dictionary.fetch(lastword) {NULL_OBJECT}.sample
   end
 
   # Generates a sentence of (wordcount) length using the weighted_random function.
@@ -68,19 +78,18 @@ def generate(wordcount)
   # @return [String] the sentence(s) generated.
   def generate_sentence(sentencecount) 
     sentence = []
+    # Find out how many actual keys are in the dictionary.
+    key_count = @dictionary.dictionary.keys.length
+    # If less than 30 keys, use that plus five as your maximum sentence length.
+    maximum_length = key_count < 30 ? key_count + 5 : 30
     sentencecount.times do
-      # Find out how many actual keys are in the dictionary.
-      key_count = @dictionary.dictionary.keys.length
-      # If less than 30 keys, use that plus five as your maximum sentence length.
-      maximum_length = key_count < 30 ? key_count + 5 : 30
-      stop_at_index = sentence.count + maximum_length
+      wordcount = 0
       sentence.concat(random_capitalized_word)
-      until (/[.!?]/ =~ sentence.last[-1])
+      until (/[.!?]/ =~ sentence.last[-1]) || wordcount > 30
+        wordcount += 1
         word = weighted_random(sentence.last(@depth))
-        sentence << word unless word.nil?
-        # If a word ending with a . ! or ?  isn't found after 30 words,
-        # just add a period as there may be none in the dictionary.
-        sentence[-1] << "." if word.nil? || sentence.count > stop_at_index
+        sentence << word
+        sentence[-1] << "." if wordcount == 30
       end
     end
     sentence.join(' ')

marky_markov.gemspec

@@ -13,8 +13,8 @@ Gem::Specification.new do |s|
   ## If your rubyforge_project name is different, then edit it and comment out
   ## the sub! line in the Rakefile
   s.name              = 'marky_markov'
-  s.version           = '0.3.0'
-  s.date              = '2012-02-09'
+  s.version           = '0.3.1'
+  s.date              = '2012-02-10'
   s.rubyforge_project = 'marky_markov'
 
   ## Make sure your summary is short. The description may be as long