require 'singleton'
module ActiveSupport
# 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.
#
# The Rails core team has stated patches for the inflections library will not be accepted
# in order to avoid breaking legacy applications which may be relying on errant inflections.
# If you discover an incorrect inflection and require it for your application, you'll need
# to correct it yourself (explained below).
module Inflector
extend self
# A singleton instance of this class is yielded by Inflector.inflections, which can then be used to specify additional
# inflection rules. Examples:
#
# ActiveSupport::Inflector.inflections do |inflect|
# inflect.plural /^(ox)$/i, '\1\2en'
# inflect.singular /^(ox)en/i, '\1'
#
# inflect.irregular 'octopus', 'octopi'
#
# inflect.uncountable "equipment"
# end
#
# New rules are added at the top. So in the example above, the irregular rule for octopus will now be the first of the
# pluralization and singularization rules that is runs. This guarantees that your rules run before any of the rules that may
# already have been loaded.
class Inflections
include Singleton
attr_reader :plurals, :singulars, :uncountables
def initialize
@plurals, @singulars, @uncountables = [], [], []
end
# Specifies a new pluralization rule and its replacement. The rule can either be a string or a regular expression.
# The replacement should always be a string that may include references to the matched data from the rule.
def plural(rule, replacement)
@plurals.insert(0, [rule, replacement])
end
# Specifies a new singularization rule and its replacement. The rule can either be a string or a regular expression.
# The replacement should always be a string that may include references to the matched data from the rule.
def singular(rule, replacement)
@singulars.insert(0, [rule, replacement])
end
# Specifies a new irregular that applies to both pluralization and singularization at the same time. This can only be used
# for strings, not regular expressions. You simply pass the irregular in singular and plural form.
#
# Examples:
# irregular 'octopus', 'octopi'
# irregular 'person', 'people'
def irregular(singular, plural)
if singular[0,1].upcase == plural[0,1].upcase
plural(Regexp.new("(#{singular[0,1]})#{singular[1..-1]}$", "i"), '\1' + plural[1..-1])
singular(Regexp.new("(#{plural[0,1]})#{plural[1..-1]}$", "i"), '\1' + singular[1..-1])
else
plural(Regexp.new("#{singular[0,1].upcase}(?i)#{singular[1..-1]}$"), plural[0,1].upcase + plural[1..-1])
plural(Regexp.new("#{singular[0,1].downcase}(?i)#{singular[1..-1]}$"), plural[0,1].downcase + plural[1..-1])
singular(Regexp.new("#{plural[0,1].upcase}(?i)#{plural[1..-1]}$"), singular[0,1].upcase + singular[1..-1])
singular(Regexp.new("#{plural[0,1].downcase}(?i)#{plural[1..-1]}$"), singular[0,1].downcase + singular[1..-1])
end
end
# Add uncountable words that shouldn't be attempted inflected.
#
# Examples:
# uncountable "money"
# uncountable "money", "information"
# uncountable %w( money information rice )
def uncountable(*words)
(@uncountables << words).flatten!
end
# Clears the loaded inflections within a given scope (default is <tt>:all</tt>).
# Give the scope as a symbol of the inflection type, the options are: <tt>:plurals</tt>,
# <tt>:singulars</tt>, <tt>:uncountables</tt>.
#
# Examples:
# clear :all
# clear :plurals
def clear(scope = :all)
case scope
when :all
@plurals, @singulars, @uncountables = [], [], []
else
instance_variable_set "@#{scope}", []
end
end
end
# Yields a singleton instance of Inflector::Inflections so you can specify additional
# inflector rules.
#
# Example:
# ActiveSupport::Inflector.inflections do |inflect|
# inflect.uncountable "rails"
# end
def inflections
if block_given?
yield Inflections.instance
else
Inflections.instance
end
end
# 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"
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
# 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".singularize # => "word"
# "the blue mailmen".singularize # => "the blue mailman"
# "CamelOctopi".singularize # => "CamelOctopus"
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
# 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.
#
# Examples:
# "active_record".camelize # => "ActiveRecord"
# "active_record".camelize(:lower) # => "activeRecord"
# "active_record/errors".camelize # => "ActiveRecord::Errors"
# "active_record/errors".camelize(:lower) # => "activeRecord::Errors"
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(/\/(.?)/) { "::#{$1.upcase}" }.gsub(/(?:^|_)(.)/) { $1.upcase }
else
lower_case_and_underscored_word.first + camelize(lower_case_and_underscored_word)[1..-1]
end
end
# 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"
def titleize(word)
humanize(underscore(word)).gsub(/\b('?[a-z])/) { $1.capitalize }
end
# The reverse of +camelize+. Makes an underscored, lowercase form from the expression in the string.
#
# Changes '::' to '/' to convert namespaces to paths.
#
# Examples:
# "ActiveRecord".underscore # => "active_record"
# "ActiveRecord::Errors".underscore # => active_record/errors
def underscore(camel_cased_word)
camel_cased_word.to_s.gsub(/::/, '/').
gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
gsub(/([a-z\d])([A-Z])/,'\1_\2').
tr("-", "_").
downcase
end
# Replaces underscores with dashes in the string.
#
# Example:
# "puni_puni" # => "puni-puni"
def dasherize(underscored_word)
underscored_word.gsub(/_/, '-')
end
# Capitalizes the first word and turns underscores into spaces and strips a
# trailing "_id", if any. Like +titleize+, this is meant for creating pretty output.
#
# Examples:
# "employee_salary" # => "Employee salary"
# "author_id" # => "Author"
def humanize(lower_case_and_underscored_word)
lower_case_and_underscored_word.to_s.gsub(/_id$/, "").gsub(/_/, " ").capitalize
end
# Removes the module part from the expression in the string.
#
# Examples:
# "ActiveRecord::CoreExtensions::String::Inflections".demodulize # => "Inflections"
# "Inflections".demodulize # => "Inflections"
def demodulize(class_name_in_module)
class_name_in_module.to_s.gsub(/^.*::/, '')
end
# 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"
def tableize(class_name)
pluralize(underscore(class_name))
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+.)
#
# Examples:
# "egg_and_hams".classify # => "EggAndHam"
# "posts".classify # => "Post"
#
# Singular names are not handled correctly:
# "business".classify # => "Busines"
def classify(table_name)
# strip out any leading schema name
camelize(singularize(table_name.to_s.sub(/.*\./, '')))
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(class_name, separate_class_name_and_id_with_underscore = true)
underscore(demodulize(class_name)) + (separate_class_name_and_id_with_underscore ? "_id" : "id")
end
# Tries to find a constant with the name specified in the argument string:
#
# "Module".constantize # => Module
# "Test::Unit".constantize # => Test::Unit
#
# The name is assumed to be the one of a top-level constant, no matter whether
# it starts with "::" or not. No lexical context is taken into account:
#
# C = 'outside'
# module M
# C = 'inside'
# C # => 'inside'
# "C".constantize # => 'outside', same as ::C
# end
#
# NameError is raised when the name is not in CamelCase or the constant is
# unknown.
def constantize(camel_cased_word)
unless /\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
# 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"
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
end
end
require 'active_support/inflections'
