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diff --git a/activesupport/lib/active_support/inflector.rb b/activesupport/lib/active_support/inflector.rb
new file mode 100644
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+++ b/activesupport/lib/active_support/inflector.rb
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+# The Inflector transforms words from singular to plural, class names to table names, modularized class names to ones without,
+# and class names to foreign keys.
+module Inflector 
+  extend self
+
+  def pluralize(word)
+    result = word.to_s.dup
+    plural_rules.each do |(rule, replacement)|
+      break if result.gsub!(rule, replacement)
+    end
+    return result
+  end
+
+  def singularize(word)
+    result = word.to_s.dup
+    singular_rules.each do |(rule, replacement)|
+      break if result.gsub!(rule, replacement)
+    end
+    return result
+  end
+
+  def camelize(lower_case_and_underscored_word)
+    lower_case_and_underscored_word.to_s.gsub(/\/(.?)/) { "::" + $1.upcase }.gsub(/(^|_)(.)/) { $2.upcase }
+  end
+  
+  def underscore(camel_cased_word)
+    camel_cased_word.to_s.gsub(/::/, '/').gsub(/([A-Z]+)([A-Z])/,'\1_\2').gsub(/([a-z])([A-Z])/,'\1_\2').downcase
+  end
+
+  def humanize(lower_case_and_underscored_word)
+    lower_case_and_underscored_word.to_s.gsub(/_/, " ").capitalize
+  end
+
+  def demodulize(class_name_in_module)
+    class_name_in_module.to_s.gsub(/^.*::/, '')
+  end
+
+  def tableize(class_name)
+    pluralize(underscore(class_name))
+  end
+  
+  def classify(table_name)
+    camelize(singularize(table_name))
+  end
+
+  def foreign_key(class_name, separate_class_name_and_id_with_underscore = true)
+    Inflector.underscore(Inflector.demodulize(class_name)) + 
+      (separate_class_name_and_id_with_underscore ? "_id" : "id")
+  end
+
+  def constantize(camel_cased_word)
+    camel_cased_word.split("::").inject(Object) do |final_type, part| 
+      final_type = final_type.const_get(part)
+    end
+  end
+
+  private
+    def plural_rules #:doc:
+      [
+        [/(x|ch|ss|sh)$/, '\1es'],               # search, switch, fix, box, process, address
+        [/series$/, '\1series'],
+        [/([^aeiouy]|qu)ies$/, '\1y'],
+        [/([^aeiouy]|qu)y$/, '\1ies'],        # query, ability, agency
+        [/(?:([^f])fe|([lr])f)$/, '\1\2ves'], # half, safe, wife
+        [/sis$/, 'ses'],                      # basis, diagnosis
+        [/([ti])um$/, '\1a'],                 # datum, medium
+        [/person$/, 'people'],                # person, salesperson
+        [/man$/, 'men'],                      # man, woman, spokesman
+        [/child$/, 'children'],               # child
+        [/s$/, 's'],                          # no change (compatibility)
+        [/$/, 's']
+      ]
+    end
+
+    def singular_rules #:doc:
+      [
+        [/(x|ch|ss)es$/, '\1'],
+        [/movies$/, 'movie'],
+        [/series$/, 'series'],
+        [/([^aeiouy]|qu)ies$/, '\1y'],
+        [/([lr])ves$/, '\1f'],
+        [/([^f])ves$/, '\1fe'],
+        [/(analy|ba|diagno|parenthe|progno|synop|the)ses$/, '\1sis'],
+        [/([ti])a$/, '\1um'],
+        [/people$/, 'person'],
+        [/men$/, 'man'],
+        [/status$/, 'status'],
+        [/children$/, 'child'],
+        [/news$/, 'news'],
+        [/s$/, '']
+      ]
+    end
+end