module Inflector

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. The default inflections for pluralization, singularization, and uncountable words are kept in inflections.rb.

Public Instance Methods

camelize(lower_case_and_underscored_word, first_letter_in_uppercase = true) click to toggle source

By default, camelize converts strings to UpperCamelCase. If the argument to camelize is set to “:lower” then camelize produces lowerCamelCase.

camelize will also convert ‘/’ to ‘::’ which is useful for converting paths to namespaces

Examples

"active_record".camelize #=> "ActiveRecord"
"active_record".camelize(:lower) #=> "activeRecord"
"active_record/errors".camelize #=> "ActiveRecord::Errors"
"active_record/errors".camelize(:lower) #=> "activeRecord::Errors"
# File lib/inflector.rb, line 147
def camelize(lower_case_and_underscored_word, first_letter_in_uppercase = true)
  if first_letter_in_uppercase
    lower_case_and_underscored_word.to_s.gsub(%r\/(.?)/) { "::#{$1.upcase}" }.gsub(%r(?:^|_)(.)/) { $1.upcase }
  else
    lower_case_and_underscored_word.first + camelize(lower_case_and_underscored_word)[1..-1]
  end
end
classify(table_name) click to toggle source

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.)

Examples

"egg_and_hams".classify #=> "EggAndHam"
"posts".classify #=> "Post"

Singular names are not handled correctly

"business".classify #=> "Busines"
# File lib/inflector.rb, line 231
def classify(table_name)
  # strip out any leading schema name
  camelize(singularize(table_name.to_s.sub(%r.*\./, '')))
end
constantize(camel_cased_word) click to toggle source

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
# File lib/inflector.rb, line 255
def constantize(camel_cased_word)
  unless %r\A(?:::)?([A-Z]\w*(?:::[A-Z]\w*)*)\z/ =~ camel_cased_word
    raise NameError, "#{camel_cased_word.inspect} is not a valid constant name!"
  end

  Object.module_eval("::#{$1}", __FILE__, __LINE__)
end
dasherize(underscored_word) click to toggle source

Replaces underscores with dashes in the string.

Example

"puni_puni" #=> "puni-puni"
# File lib/inflector.rb, line 187
def dasherize(underscored_word)
  underscored_word.gsub(%r_/, '-')
end
demodulize(class_name_in_module) click to toggle source

Removes the module part from the expression in the string

Examples

"ActiveRecord::CoreExtensions::String::Inflections".demodulize #=> "Inflections"
"Inflections".demodulize #=> "Inflections"
# File lib/inflector.rb, line 206
def demodulize(class_name_in_module)
  class_name_in_module.to_s.gsub(%r^.*::/, '')
end
foreign_key(class_name, separate_class_name_and_id_with_underscore = true) click to toggle source

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"
# File lib/inflector.rb, line 244
def foreign_key(class_name, separate_class_name_and_id_with_underscore = true)
  underscore(demodulize(class_name)) + (separate_class_name_and_id_with_underscore ? "_id" : "id")
end
humanize(lower_case_and_underscored_word) click to toggle source

Capitalizes the first word and turns underscores into spaces and strips _id. Like titleize, this is meant for creating pretty output.

Examples

"employee_salary" #=> "Employee salary"
"author_id" #=> "Author"
# File lib/inflector.rb, line 197
def humanize(lower_case_and_underscored_word)
  lower_case_and_underscored_word.to_s.gsub(%r_id$/, "").gsub(%r_/, " ").capitalize
end
inflections() { |instance| ... } click to toggle source
# File lib/inflector.rb, line 89
def inflections
  if block_given?
    yield Inflections.instance
  else
    Inflections.instance
  end
end
ordinalize(number) click to toggle source

Ordinalize turns a number into an ordinal string used to denote the position in an ordered sequence such as 1st, 2nd, 3rd, 4th.

Examples

ordinalize(1)     # => "1st"
ordinalize(2)     # => "2nd"
ordinalize(1002)  # => "1002nd"
ordinalize(1003)  # => "1003rd"
# File lib/inflector.rb, line 271
def ordinalize(number)
  if (11..13).include?(number.to_i % 100)
    "#{number}th"
  else
    case number.to_i % 10
      when 1; "#{number}st"
      when 2; "#{number}nd"
      when 3; "#{number}rd"
      else    "#{number}th"
    end
  end
end
pluralize(word) click to toggle source

Returns the plural form of the word in the string.

Examples

"post".pluralize #=> "posts"
"octopus".pluralize #=> "octopi"
"sheep".pluralize #=> "sheep"
"words".pluralize #=> "words"
"the blue mailman".pluralize #=> "the blue mailmen"
"CamelOctopus".pluralize #=> "CamelOctopi"
# File lib/inflector.rb, line 106
def pluralize(word)
  result = word.to_s.dup

  if word.empty? || inflections.uncountables.include?(result.downcase)
    result
  else
    inflections.plurals.each { |(rule, replacement)| break if result.gsub!(rule, replacement) }
    result
  end
end
singularize(word) click to toggle source

The reverse of pluralize, returns the singular form of a word in a string.

Examples

"posts".singularize #=> "post"
"octopi".singularize #=> "octopus"
"sheep".singluarize #=> "sheep"
"word".singluarize #=> "word"
"the blue mailmen".singularize #=> "the blue mailman"
"CamelOctopi".singularize #=> "CamelOctopus"
# File lib/inflector.rb, line 126
def singularize(word)
  result = word.to_s.dup

  if inflections.uncountables.include?(result.downcase)
    result
  else
    inflections.singulars.each { |(rule, replacement)| break if result.gsub!(rule, replacement) }
    result
  end
end
tableize(class_name) click to toggle source

Create 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.

Examples

"RawScaledScorer".tableize #=> "raw_scaled_scorers"
"egg_and_ham".tableize #=> "egg_and_hams"
"fancyCategory".tableize #=> "fancy_categories"
# File lib/inflector.rb, line 217
def tableize(class_name)
  pluralize(underscore(class_name))
end
titleize(word) click to toggle source

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 as titlecase

Examples

"man from the boondocks".titleize #=> "Man From The Boondocks"
"x-men: the last stand".titleize #=> "X Men: The Last Stand"
# File lib/inflector.rb, line 164
def titleize(word)
  humanize(underscore(word)).gsub(%r\b('?[a-z])/) { $1.capitalize }
end
underscore(camel_cased_word) click to toggle source

The reverse of camelize. Makes an underscored form from the expression in the string.

Changes ‘::’ to ‘/’ to convert namespaces to paths.

Examples

"ActiveRecord".underscore #=> "active_record"
"ActiveRecord::Errors".underscore #=> active_record/errors
# File lib/inflector.rb, line 175
def underscore(camel_cased_word)
  camel_cased_word.to_s.gsub(%r::/, '/').
    gsub(%r([A-Z]+)([A-Z][a-z])/,'\1_\2').
    gsub(%r([a-z\d])([A-Z])/,'\1_\2').
    tr("-", "_").
    downcase
end