require 'active_support/inflector/inflections'
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
# 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)
apply_inflections(word, inflections.plurals)
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)
apply_inflections(word, inflections.singulars)
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_model".camelize # => "ActiveModel"
# "active_model".camelize(:lower) # => "activeModel"
# "active_model/errors".camelize # => "ActiveModel::Errors"
# "active_model/errors".camelize(:lower) # => "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:
#
# "SSLError".underscore.camelize # => "SslError"
def camelize(term, uppercase_first_letter = true)
string = term.to_s
if uppercase_first_letter
string = string.sub(/^[a-z\d]*/) { inflections.acronyms[$&] || $&.capitalize }
else
string = string.sub(/^(?:#{inflections.acronym_regex}(?=\b|[A-Z_])|\w)/) { $&.downcase }
end
string.gsub(/(?:_|(\/))([a-z\d]*)/i) { "#{$1}#{inflections.acronyms[$2] || $2.capitalize}" }.gsub('/', '::')
end
# Makes an underscored, lowercase form from the expression in the string.
#
# Changes '::' to '/' to convert namespaces to paths.
#
# Examples:
# "ActiveModel".underscore # => "active_model"
# "ActiveModel::Errors".underscore # => "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:
#
# "SSLError".underscore.camelize # => "SslError"
def underscore(camel_cased_word)
word = camel_cased_word.to_s.dup
word.gsub!(/::/, '/')
word.gsub!(/(?:([A-Za-z\d])|^)(#{inflections.acronym_regex})(?=\b|[^a-z])/) { "#{$1}#{$1 && '_'}#{$2.downcase}" }
word.gsub!(/([A-Z\d]+)([A-Z][a-z])/,'\1_\2')
word.gsub!(/([a-z\d])([A-Z])/,'\1_\2')
word.tr!("-", "_")
word.downcase!
word
end
# Capitalizes the first word and turns underscores into spaces and strips a
# trailing "_id", if any. Like +titleize+, this is meant for creating pretty output.
#
# Examples:
# "employee_salary" # => "Employee salary"
# "author_id" # => "Author"
def humanize(lower_case_and_underscored_word)
result = lower_case_and_underscored_word.to_s.dup
inflections.humans.each { |(rule, replacement)| break if result.sub!(rule, replacement) }
result.gsub!(/_id$/, "")
result.tr!('_', ' ')
result.gsub(/([a-z\d]*)/i) { |match|
"#{inflections.acronyms[match] || match.downcase}"
}.gsub(/^\w/) { $&.upcase }
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"
# "TheManWithoutAPast".titleize # => "The Man Without A Past"
# "raiders_of_the_lost_ark".titleize # => "Raiders Of The Lost Ark"
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
# Replaces underscores with dashes in the string.
#
# Example:
# "puni_puni" # => "puni-puni"
def dasherize(underscored_word)
underscored_word.tr('_', '-')
end
# Removes the module part from the expression in the string:
#
# "ActiveRecord::CoreExtensions::String::Inflections".demodulize # => "Inflections"
# "Inflections".demodulize # => "Inflections"
#
# See also +deconstantize+.
def demodulize(path)
path = path.to_s
if i = path.rindex('::')
path[(i+2)..-1]
else
path
end
end
# Removes the rightmost segment from the constant expression in the string:
#
# "Net::HTTP".deconstantize # => "Net"
# "::Net::HTTP".deconstantize # => "::Net"
# "String".deconstantize # => ""
# "::String".deconstantize # => ""
# "".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'.
#
# 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) #:nodoc:
names = camel_cased_word.split('::')
names.shift if names.empty? || names.first.empty?
names.inject(Object) do |constant, name|
constant.const_get(name, false)
end
end
# Tries to find a constant with the name specified in the argument string:
#
# "Module".safe_constantize # => Module
# "Test::Unit".safe_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".safe_constantize # => 'outside', same as ::C
# end
#
# nil is returned when the name is not in CamelCase or the constant (or part of it) is
# unknown.
#
# "blargle".safe_constantize # => nil
# "UnknownModule".safe_constantize # => nil
# "UnknownModule::Foo::Bar".safe_constantize # => nil
#
def safe_constantize(camel_cased_word)
begin
constantize(camel_cased_word)
rescue NameError => e
raise unless e.message =~ /(uninitialized constant|wrong constant name) #{const_regexp(camel_cased_word)}$/ ||
e.name.to_s == camel_cased_word.to_s
rescue ArgumentError => e
raise unless e.message =~ /not missing constant #{const_regexp(camel_cased_word)}\!$/
end
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.
#
# Examples:
# ordinal(1) # => "st"
# ordinal(2) # => "nd"
# ordinal(1002) # => "nd"
# ordinal(1003) # => "rd"
# ordinal(-11) # => "th"
# ordinal(-1021) # => "st"
def ordinal(number)
if (11..13).include?(number.to_i.abs % 100)
"th"
else
case number.to_i.abs % 10
when 1; "st"
when 2; "nd"
when 3; "rd"
else "th"
end
end
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"
# ordinalize(-11) # => "-11th"
# ordinalize(-1021) # => "-1021st"
def ordinalize(number)
"#{number}#{ordinal(number)}"
end
private
# Mount a regular expression that will match part by part of the constant.
# For instance, Foo::Bar::Baz will generate Foo(::Bar(::Baz)?)?
def const_regexp(camel_cased_word) #:nodoc:
parts = camel_cased_word.split("::")
last = parts.pop
parts.reverse.inject(last) do |acc, part|
part.empty? ? acc : "#{part}(::#{acc})?"
end
end
# Applies inflection rules for +singularize+ and +pluralize+.
#
# Examples:
# apply_inflections("post", inflections.plurals) # => "posts"
# apply_inflections("posts", inflections.singulars) # => "post"
def apply_inflections(word, rules)
result = word.to_s.dup
if word.empty? || inflections.uncountables.include?(result.downcase[/\b\w+\Z/])
result
else
rules.each { |(rule, replacement)| break if result.sub!(rule, replacement) }
result
end
end
end
end
