module RailsStats::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).
Public Instance Methods
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.
'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"
# File lib/rails_stats/inflector.rb, line 270 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
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
).
'egg_and_hams'.classify # => "EggAndHam" 'posts'.classify # => "Post"
Singular names are not handled correctly:
'business'.classify # => "Busines"
# File lib/rails_stats/inflector.rb, line 352 def classify(table_name) # strip out any leading schema name camelize(singularize(table_name.to_s.sub(/.*\./, ''))) 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.
# File lib/rails_stats/inflector.rb, line 421 def constantize(camel_cased_word) names = camel_cased_word.split('::') names.shift if names.empty? || names.first.empty? names.inject(Object) do |constant, name| if constant == Object constant.const_get(name) else candidate = constant.const_get(name) next candidate if constant.const_defined?(name, false) next candidate unless Object.const_defined?(name) # Go down the ancestors to check it it's owned # directly before we reach Object or the end of ancestors. constant = constant.ancestors.inject do |const, ancestor| break const if ancestor == Object break ancestor if ancestor.const_defined?(name, false) const end # owner is in Object, so raise constant.const_get(name, false) end end end
Replaces underscores with dashes in the string.
'puni_puni'.dasherize # => "puni-puni"
# File lib/rails_stats/inflector.rb, line 360 def dasherize(underscored_word) underscored_word.tr('_', '-') 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
.
# File lib/rails_stats/inflector.rb, line 388 def deconstantize(path) path.to_s[0...(path.rindex('::') || 0)] # implementation based on the one in facets' Module#spacename end
Removes the module part from the expression in the string.
'ActiveRecord::CoreExtensions::String::Inflections'.demodulize # => "Inflections" 'Inflections'.demodulize # => "Inflections"
See also deconstantize
.
# File lib/rails_stats/inflector.rb, line 370 def demodulize(path) path = path.to_s if i = path.rindex('::') path[(i+2)..-1] else path end 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'.
'Message'.foreign_key # => "message_id" 'Message'.foreign_key(false) # => "messageid" 'Admin::Post'.foreign_key # => "post_id"
# File lib/rails_stats/inflector.rb, line 399 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
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.
'employee_salary'.humanize # => "Employee salary" 'author_id'.humanize # => "Author"
# File lib/rails_stats/inflector.rb, line 308 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
Yields a singleton instance of Inflector::Inflections
so you can specify additional inflector rules. If passed an optional locale, rules for other languages can be specified. If not specified, defaults to :en
. Only rules for English are provided.
ActiveSupport::Inflector.inflections(:en) do |inflect| inflect.uncountable 'rails' end
# File lib/rails_stats/inflector.rb, line 210 def inflections(locale = :en) if block_given? yield Inflections.instance(locale) else Inflections.instance(locale) 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.
ordinal(1) # => "st" ordinal(2) # => "nd" ordinal(1002) # => "nd" ordinal(1003) # => "rd" ordinal(-11) # => "th" ordinal(-1021) # => "st"
# File lib/rails_stats/inflector.rb, line 487 def ordinal(number) abs_number = number.to_i.abs if (11..13).include?(abs_number % 100) "th" else case abs_number % 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.
ordinalize(1) # => "1st" ordinalize(2) # => "2nd" ordinalize(1002) # => "1002nd" ordinalize(1003) # => "1003rd" ordinalize(-11) # => "-11th" ordinalize(-1021) # => "-1021st"
# File lib/rails_stats/inflector.rb, line 511 def ordinalize(number) "#{number}#{ordinal(number)}" end
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 :en
.
'post'.pluralize # => "posts" 'octopus'.pluralize # => "octopi" 'sheep'.pluralize # => "sheep" 'words'.pluralize # => "words" 'CamelOctopus'.pluralize # => "CamelOctopi" 'ley'.pluralize(:es) # => "leyes"
# File lib/rails_stats/inflector.rb, line 233 def pluralize(word, locale = :en) apply_inflections(word, inflections(locale).plurals) 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
# File lib/rails_stats/inflector.rb, line 469 def safe_constantize(camel_cased_word) 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
The reverse of pluralize
, returns the singular form of a word in a 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 :en
.
'posts'.singularize # => "post" 'octopi'.singularize # => "octopus" 'sheep'.singularize # => "sheep" 'word'.singularize # => "word" 'CamelOctopi'.singularize # => "CamelOctopus" 'leyes'.singularize(:es) # => "ley"
# File lib/rails_stats/inflector.rb, line 250 def singularize(word, locale = :en) apply_inflections(word, inflections(locale).singulars) 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.
'RawScaledScorer'.tableize # => "raw_scaled_scorers" 'egg_and_ham'.tableize # => "egg_and_hams" 'fancyCategory'.tableize # => "fancy_categories"
# File lib/rails_stats/inflector.rb, line 338 def tableize(class_name) pluralize(underscore(class_name)) 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 titlecase
.
'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"
# File lib/rails_stats/inflector.rb, line 328 def titleize(word) humanize(underscore(word)).gsub(/\b(?<!['’`])[a-z]/) { $&.capitalize } end
Makes an underscored, lowercase form from the expression in the string.
Changes '::' to '/' to convert namespaces to paths.
'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"
# File lib/rails_stats/inflector.rb, line 291 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
Private Instance Methods
Applies inflection rules for singularize
and pluralize
.
apply_inflections('post', inflections.plurals) # => "posts" apply_inflections('posts', inflections.singulars) # => "post"
# File lib/rails_stats/inflector.rb, line 532 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