activesupport/lib/active_support/inflector/methods.rb
# frozen_string_literal: true
require "active_support/inflections"
module ActiveSupport
# = Active Support \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.
#
# 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 or wish to define rules for languages other
# than English, please correct or add them yourself (explained below).
module Inflector
extend self
# Returns the plural form of the word in the string.
#
# If passed an optional +locale+ parameter, the word will be
# pluralized using rules defined for that language. By default,
# this parameter is set to <tt>:en</tt>.
#
# pluralize('post') # => "posts"
# pluralize('octopus') # => "octopi"
# pluralize('sheep') # => "sheep"
# pluralize('words') # => "words"
# pluralize('CamelOctopus') # => "CamelOctopi"
# pluralize('ley', :es) # => "leyes"
def pluralize(word, locale = :en)
apply_inflections(word, inflections(locale).plurals, locale)
end
# The reverse of #pluralize, returns the singular form of a word in a
# string.
#
# If passed an optional +locale+ parameter, the word will be
# singularized using rules defined for that language. By default,
# this parameter is set to <tt>:en</tt>.
#
# singularize('posts') # => "post"
# singularize('octopi') # => "octopus"
# singularize('sheep') # => "sheep"
# singularize('word') # => "word"
# singularize('CamelOctopi') # => "CamelOctopus"
# singularize('leyes', :es) # => "ley"
def singularize(word, locale = :en)
apply_inflections(word, inflections(locale).singulars, locale)
end
# Converts strings to UpperCamelCase.
# If the +uppercase_first_letter+ parameter is set to false, then produces
# lowerCamelCase.
#
# Also converts '/' to '::' which is useful for converting
# paths to namespaces.
#
# camelize('active_model') # => "ActiveModel"
# camelize('active_model', false) # => "activeModel"
# camelize('active_model/errors') # => "ActiveModel::Errors"
# camelize('active_model/errors', false) # => "activeModel::Errors"
#
# As a rule of thumb you can think of +camelize+ as the inverse of
# #underscore, though there are cases where that does not hold:
#
# camelize(underscore('SSLError')) # => "SslError"
def camelize(term, uppercase_first_letter = true)
string = term.to_s
# String#camelize takes a symbol (:upper or :lower), so here we also support :lower to keep the methods consistent.
if !uppercase_first_letter || uppercase_first_letter == :lower
string = string.sub(inflections.acronyms_camelize_regex) { |match| match.downcase! || match }
elsif string.match?(/\A[a-z\d]*\z/)
return inflections.acronyms[string]&.dup || string.capitalize
else
string = string.sub(/^[a-z\d]*/) { |match| inflections.acronyms[match] || match.capitalize! || match }
end
string.gsub!(/(?:_|(\/))([a-z\d]*)/i) do
word = $2
substituted = inflections.acronyms[word] || word.capitalize! || word
$1 ? "::#{substituted}" : substituted
end
string
end
# Makes an underscored, lowercase form from the expression in the string.
#
# Changes '::' to '/' to convert namespaces to paths.
#
# underscore('ActiveModel') # => "active_model"
# underscore('ActiveModel::Errors') # => "active_model/errors"
#
# As a rule of thumb you can think of +underscore+ as the inverse of
# #camelize, though there are cases where that does not hold:
#
# camelize(underscore('SSLError')) # => "SslError"
def underscore(camel_cased_word)
return camel_cased_word.to_s.dup unless /[A-Z-]|::/.match?(camel_cased_word)
word = camel_cased_word.to_s.gsub("::", "/")
word.gsub!(inflections.acronyms_underscore_regex) { "#{$1 && '_' }#{$2.downcase}" }
word.gsub!(/(?<=[A-Z])(?=[A-Z][a-z])|(?<=[a-z\d])(?=[A-Z])/, "_")
word.tr!("-", "_")
word.downcase!
word
end
# Tweaks an attribute name for display to end users.
#
# Specifically, performs these transformations:
#
# * Applies human inflection rules to the argument.
# * Deletes leading underscores, if any.
# * Removes an "_id" suffix if present.
# * Replaces underscores with spaces, if any.
# * Downcases all words except acronyms.
# * Capitalizes the first word.
# The capitalization of the first word can be turned off by setting the
# +:capitalize+ option to false (default is true).
#
# The trailing '_id' can be kept and capitalized by setting the
# optional parameter +keep_id_suffix+ to true (default is false).
#
# humanize('employee_salary') # => "Employee salary"
# humanize('author_id') # => "Author"
# humanize('author_id', capitalize: false) # => "author"
# humanize('_id') # => "Id"
# humanize('author_id', keep_id_suffix: true) # => "Author id"
#
# If "SSL" was defined to be an acronym:
#
# humanize('ssl_error') # => "SSL error"
#
def humanize(lower_case_and_underscored_word, capitalize: true, keep_id_suffix: false)
result = lower_case_and_underscored_word.to_s.dup
inflections.humans.each { |(rule, replacement)| break if result.sub!(rule, replacement) }
result.tr!("_", " ")
result.lstrip!
if !keep_id_suffix && lower_case_and_underscored_word&.end_with?("_id")
result.delete_suffix!(" id")
end
result.gsub!(/([a-z\d]+)/i) do |match|
match.downcase!
inflections.acronyms[match] || match
end
if capitalize
result.sub!(/\A\w/) do |match|
match.upcase!
match
end
end
result
end
# Converts the first character in the string to uppercase.
#
# upcase_first('what a Lovely Day') # => "What a Lovely Day"
# upcase_first('w') # => "W"
# upcase_first('') # => ""
def upcase_first(string)
string.length > 0 ? string[0].upcase.concat(string[1..-1]) : +""
end
# Converts the first character in the string to lowercase.
#
# downcase_first('If they enjoyed The Matrix') # => "if they enjoyed The Matrix"
# downcase_first('I') # => "i"
# downcase_first('') # => ""
def downcase_first(string)
string.length > 0 ? string[0].downcase.concat(string[1..-1]) : +""
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.
#
# The trailing '_id','Id'.. can be kept and capitalized by setting the
# optional parameter +keep_id_suffix+ to true.
# By default, this parameter is false.
#
# titleize('man from the boondocks') # => "Man From The Boondocks"
# titleize('x-men: the last stand') # => "X Men: The Last Stand"
# titleize('TheManWithoutAPast') # => "The Man Without A Past"
# titleize('raiders_of_the_lost_ark') # => "Raiders Of The Lost Ark"
# titleize('string_ending_with_id', keep_id_suffix: true) # => "String Ending With Id"
def titleize(word, keep_id_suffix: false)
humanize(underscore(word), keep_id_suffix: keep_id_suffix).gsub(/\b(?<!\w['’`()])[a-z]/) do |match|
match.capitalize
end
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.
#
# tableize('RawScaledScorer') # => "raw_scaled_scorers"
# tableize('ham_and_egg') # => "ham_and_eggs"
# tableize('fancyCategory') # => "fancy_categories"
def tableize(class_name)
pluralize(underscore(class_name))
end
# Creates 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.)
#
# classify('ham_and_eggs') # => "HamAndEgg"
# classify('posts') # => "Post"
#
# Singular names are not handled correctly:
#
# classify('calculus') # => "Calculu"
def classify(table_name)
# strip out any leading schema name
camelize(singularize(table_name.to_s.sub(/.*\./, "")))
end
# Replaces underscores with dashes in the string.
#
# dasherize('puni_puni') # => "puni-puni"
def dasherize(underscored_word)
underscored_word.tr("_", "-")
end
# Removes the module part from the expression in the string.
#
# demodulize('ActiveSupport::Inflector::Inflections') # => "Inflections"
# demodulize('Inflections') # => "Inflections"
# demodulize('::Inflections') # => "Inflections"
# demodulize('') # => ""
#
# See also #deconstantize.
def demodulize(path)
path = path.to_s
if i = path.rindex("::")
path[(i + 2), path.length]
else
path
end
end
# Removes the rightmost segment from the constant expression in the string.
#
# deconstantize('Net::HTTP') # => "Net"
# deconstantize('::Net::HTTP') # => "::Net"
# deconstantize('String') # => ""
# deconstantize('::String') # => ""
# deconstantize('') # => ""
#
# See also #demodulize.
def deconstantize(path)
path.to_s[0, path.rindex("::") || 0] # implementation based on the one in facets' Module#spacename
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'.
#
# foreign_key('Message') # => "message_id"
# foreign_key('Message', false) # => "messageid"
# foreign_key('Admin::Post') # => "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.
#
# constantize('Module') # => Module
# constantize('Foo::Bar') # => Foo::Bar
#
# 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'
# constantize('C') # => '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)
Object.const_get(camel_cased_word)
end
# Tries to find a constant with the name specified in the argument string.
#
# safe_constantize('Module') # => Module
# safe_constantize('Foo::Bar') # => Foo::Bar
#
# 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'
# safe_constantize('C') # => 'outside', same as ::C
# end
#
# +nil+ is returned when the name is not in CamelCase or the constant (or
# part of it) is unknown.
#
# safe_constantize('blargle') # => nil
# safe_constantize('UnknownModule') # => nil
# safe_constantize('UnknownModule::Foo::Bar') # => nil
def safe_constantize(camel_cased_word)
constantize(camel_cased_word)
rescue NameError => e
raise if e.name && !(camel_cased_word.to_s.split("::").include?(e.name.to_s) ||
e.name.to_s == camel_cased_word.to_s)
rescue LoadError => e
message = e.respond_to?(:original_message) ? e.original_message : e.message
raise unless /Unable to autoload constant #{const_regexp(camel_cased_word)}/.match?(message)
end
# Returns the suffix that should be added to a number to denote the position
# in an ordered sequence such as 1st, 2nd, 3rd, 4th.
#
# ordinal(1) # => "st"
# ordinal(2) # => "nd"
# ordinal(1002) # => "nd"
# ordinal(1003) # => "rd"
# ordinal(-11) # => "th"
# ordinal(-1021) # => "st"
def ordinal(number)
I18n.translate("number.nth.ordinals", number: number)
end
# Turns a number into an ordinal string used to denote the position in an
# ordered sequence such as 1st, 2nd, 3rd, 4th.
#
# ordinalize(1) # => "1st"
# ordinalize(2) # => "2nd"
# ordinalize(1002) # => "1002nd"
# ordinalize(1003) # => "1003rd"
# ordinalize(-11) # => "-11th"
# ordinalize(-1021) # => "-1021st"
def ordinalize(number)
I18n.translate("number.nth.ordinalized", number: number)
end
private
# Mounts a regular expression, returned as a string to ease interpolation,
# that will match part by part the given constant.
#
# const_regexp("Foo::Bar::Baz") # => "Foo(::Bar(::Baz)?)?"
# const_regexp("::") # => "::"
def const_regexp(camel_cased_word)
parts = camel_cased_word.split("::")
return Regexp.escape(camel_cased_word) if parts.empty?
last = parts.pop
parts.reverse!.inject(last) do |acc, part|
part.empty? ? acc : "#{part}(::#{acc})?"
end
end
# Applies inflection rules for +singularize+ and +pluralize+.
#
# If passed an optional +locale+ parameter, the uncountables will be
# found for that locale.
#
# apply_inflections('post', inflections.plurals, :en) # => "posts"
# apply_inflections('posts', inflections.singulars, :en) # => "post"
def apply_inflections(word, rules, locale = :en)
result = word.to_s.dup
if word.empty? || inflections(locale).uncountables.uncountable?(result)
result
else
rules.each { |(rule, replacement)| break if result.sub!(rule, replacement) }
result
end
end
end
end