module ActiveSupport
module Inflector
# 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)$/i, '\1\2en'
# inflect.singular /^(ox)en/i, '\1'
#
# inflect.irregular 'octopus', 'octopi'
#
# inflect.uncountable "equipment"
# end
#
# New rules are added at the top. So in the example above, the irregular rule for octopus will now be the first of the
# pluralization and singularization rules that is runs. This guarantees that your rules run before any of the rules that may
# already have been loaded.
class Inflections
def self.instance
@__instance__ ||= new
end
attr_reader :plurals, :singulars, :uncountables, :humans
def initialize
@plurals, @singulars, @uncountables, @humans = [], [], [], []
end
# Specifies a new pluralization rule and its replacement. The rule can either be a string or a regular expression.
# The replacement should always be a string that may include references to the matched data from the rule.
def plural(rule, replacement)
@uncountables.delete(rule) if rule.is_a?(String)
@uncountables.delete(replacement)
@plurals.insert(0, [rule, replacement])
end
# Specifies a new singularization rule and its replacement. The rule can either be a string or a regular expression.
# The replacement should always be a string that may include references to the matched data from the rule.
def singular(rule, replacement)
@uncountables.delete(rule) if rule.is_a?(String)
@uncountables.delete(replacement)
@singulars.insert(0, [rule, replacement])
end
# Specifies a new irregular that applies to both pluralization and singularization at the same time. This can only be used
# for strings, not regular expressions. You simply pass the irregular in singular and plural form.
#
# Examples:
# irregular 'octopus', 'octopi'
# irregular 'person', 'people'
def irregular(singular, plural)
@uncountables.delete(singular)
@uncountables.delete(plural)
if singular[0,1].upcase == plural[0,1].upcase
plural(Regexp.new("(#{singular[0,1]})#{singular[1..-1]}$", "i"), '\1' + plural[1..-1])
plural(Regexp.new("(#{plural[0,1]})#{plural[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])
plural(Regexp.new("#{plural[0,1].upcase}(?i)#{plural[1..-1]}$"), plural[0,1].upcase + plural[1..-1])
plural(Regexp.new("#{plural[0,1].downcase}(?i)#{plural[1..-1]}$"), 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
# Specifies a humanized form of a string by a regular expression rule or by a string mapping.
# When using a regular expression based replacement, the normal humanize formatting is called after the replacement.
# When a string is used, the human form should be specified as desired (example: 'The name', not 'the_name')
#
# Examples:
# human /_cnt$/i, '\1_count'
# human "legacy_col_person_name", "Name"
def human(rule, replacement)
@humans.insert(0, [rule, replacement])
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>, <tt>:humans</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"
# "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".singularize # => "sheep"
# "word".singularize # => "word"
# "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
# 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)
result = lower_case_and_underscored_word.to_s.dup
inflections.humans.each { |(rule, replacement)| break if result.gsub!(rule, replacement) }
result.gsub(/_id$/, "").gsub(/_/, " ").capitalize
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
# 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
end
end
