path: root/activesupport/lib/active_support/core_ext/string/inflections.rb

require 'active_support/inflector'

module ActiveSupport #:nodoc:
  module CoreExtensions #:nodoc:
    module String #:nodoc:
      # String inflections define new methods on the String class to transform names for different purposes.
      # For instance, you can figure out the name of a database from the name of a class.
      #
      #   "ScaleScore".tableize # => "scale_scores"
      module Inflections
        # Returns the plural form of the word in the string.
        #
        #   "post".pluralize             # => "posts"
        #   "octopus".pluralize          # => "octopi"
        #   "sheep".pluralize            # => "sheep"
        #   "words".pluralize            # => "words"
        #   "the blue mailman".pluralize # => "the blue mailmen"
        #   "CamelOctopus".pluralize     # => "CamelOctopi"
        def pluralize
          Inflector.pluralize(self)
        end

        # The reverse of +pluralize+, returns the singular form of a word in a string.
        #
        #   "posts".singularize            # => "post"
        #   "octopi".singularize           # => "octopus"
        #   "sheep".singularize            # => "sheep"
        #   "word".singularize             # => "word"
        #   "the blue mailmen".singularize # => "the blue mailman"
        #   "CamelOctopi".singularize      # => "CamelOctopus"
        def singularize
          Inflector.singularize(self)
        end

        # By default, +camelize+ converts strings to UpperCamelCase. If the argument to camelize
        # is set to <tt>:lower</tt> then camelize produces lowerCamelCase.
        #
        # +camelize+ will also convert '/' to '::' which is useful for converting paths to namespaces.
        #
        #   "active_record".camelize                # => "ActiveRecord"
        #   "active_record".camelize(:lower)        # => "activeRecord"
        #   "active_record/errors".camelize         # => "ActiveRecord::Errors"
        #   "active_record/errors".camelize(:lower) # => "activeRecord::Errors"
        def camelize(first_letter = :upper)
          case first_letter
            when :upper then Inflector.camelize(self, true)
            when :lower then Inflector.camelize(self, false)
          end
        end
        alias_method :camelcase, :camelize

        # Capitalizes all the words and replaces some characters in the string to create
        # a nicer looking title. +titleize+ is meant for creating pretty output. It is not
        # used in the Rails internals.
        #
        # +titleize+ is also aliased as +titlecase+.
        #
        #   "man from the boondocks".titleize # => "Man From The Boondocks"
        #   "x-men: the last stand".titleize  # => "X Men: The Last Stand"
        def titleize
          Inflector.titleize(self)
        end
        alias_method :titlecase, :titleize

        # The reverse of +camelize+. Makes an underscored, lowercase form from the expression in the string.
        # 
        # +underscore+ will also change '::' to '/' to convert namespaces to paths.
        #
        #   "ActiveRecord".underscore         # => "active_record"
        #   "ActiveRecord::Errors".underscore # => active_record/errors
        def underscore
          Inflector.underscore(self)
        end

        # Replaces underscores with dashes in the string.
        #
        #   "puni_puni" # => "puni-puni"
        def dasherize
          Inflector.dasherize(self)
        end

        # Removes the module part from the constant expression in the string.
        #
        #   "ActiveRecord::CoreExtensions::String::Inflections".demodulize # => "Inflections"
        #   "Inflections".demodulize                                       # => "Inflections"
        def demodulize
          Inflector.demodulize(self)
        end

        # Replaces special characters in a string so that it may be used as part of a 'pretty' URL.
        # 
        # ==== Examples
        #
        #   class Person
        #     def to_param
        #       "#{id}-#{name.parameterize}"
        #     end
        #   end
        # 
        #   @person = Person.find(1)
        #   # => #<Person id: 1, name: "Donald E. Knuth">
        # 
        #   <%= link_to(@person.name, person_path %>
        #   # => <a href="/person/1-donald-e-knuth">Donald E. Knuth</a>
        def parameterize
          Inflector.parameterize(self)
        end

        # Creates the name of a table like Rails does for models to table names. This method
        # uses the +pluralize+ method on the last word in the string.
        #
        #   "RawScaledScorer".tableize # => "raw_scaled_scorers"
        #   "egg_and_ham".tableize     # => "egg_and_hams"
        #   "fancyCategory".tableize   # => "fancy_categories"
        def tableize
          Inflector.tableize(self)
        end

        # Create a class name from a plural table name like Rails does for table names to models.
        # Note that this returns a string and not a class. (To convert to an actual class
        # follow +classify+ with +constantize+.)
        #
        #   "egg_and_hams".classify # => "EggAndHam"
        #   "posts".classify        # => "Post"
        #
        # Singular names are not handled correctly.
        #
        #   "business".classify # => "Busines"
        def classify
          Inflector.classify(self)
        end
        
        # Capitalizes the first word, turns underscores into spaces, and strips '_id'.
        # Like +titleize+, this is meant for creating pretty output.
        #
        #   "employee_salary" # => "Employee salary" 
        #   "author_id"       # => "Author"
        def humanize
          Inflector.humanize(self)
        end

        # Creates a foreign key name from a class name.
        # +separate_class_name_and_id_with_underscore+ sets whether
        # the method should put '_' between the name and 'id'.
        #
        # Examples
        #   "Message".foreign_key        # => "message_id"
        #   "Message".foreign_key(false) # => "messageid"
        #   "Admin::Post".foreign_key    # => "post_id"
        def foreign_key(separate_class_name_and_id_with_underscore = true)
          Inflector.foreign_key(self, separate_class_name_and_id_with_underscore)
        end

        # +constantize+ tries to find a declared constant with the name specified
        # in the string. It raises a NameError when the name is not in CamelCase
        # or is not initialized.
        #
        # Examples
        #   "Module".constantize # => Module
        #   "Class".constantize  # => Class
        def constantize
          Inflector.constantize(self)
        end
      end
    end
  end
end