Module: ActiveSupport::Inflector
- Extended by:
- Inflector
- Included in:
- Inflector
- Defined in:
- lib/active_support/inflector/methods.rb,
lib/active_support/inflector/inflections.rb,
lib/active_support/inflector/transliterate.rb
Overview
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).
Defined Under Namespace
Classes: Inflections
Instance Method Summary collapse
-
#camelize(term, uppercase_first_letter = true) ⇒ Object
By default,
camelize
converts strings to UpperCamelCase. -
#classify(table_name) ⇒ Object
Create a class name from a plural table name like Rails does for table names to models.
-
#constantize(camel_cased_word) ⇒ Object
:nodoc:.
-
#dasherize(underscored_word) ⇒ Object
Replaces underscores with dashes in the string.
-
#deconstantize(path) ⇒ Object
Removes the rightmost segment from the constant expression in the string:.
-
#demodulize(path) ⇒ Object
Removes the module part from the expression in the string:.
-
#foreign_key(class_name, separate_class_name_and_id_with_underscore = true) ⇒ Object
Creates a foreign key name from a class name.
-
#humanize(lower_case_and_underscored_word) ⇒ Object
Capitalizes the first word and turns underscores into spaces and strips a trailing “_id”, if any.
-
#inflections ⇒ Object
Yields a singleton instance of Inflector::Inflections so you can specify additional inflector rules.
-
#ordinalize(number) ⇒ Object
Turns a number into an ordinal string used to denote the position in an ordered sequence such as 1st, 2nd, 3rd, 4th.
-
#parameterize(string, sep = '-') ⇒ Object
Replaces special characters in a string so that it may be used as part of a ‘pretty’ URL.
-
#pluralize(word) ⇒ Object
Returns the plural form of the word in the string.
-
#safe_constantize(camel_cased_word) ⇒ Object
Tries to find a constant with the name specified in the argument string:.
-
#singularize(word) ⇒ Object
The reverse of
pluralize
, returns the singular form of a word in a string. -
#tableize(class_name) ⇒ Object
Create the name of a table like Rails does for models to table names.
-
#titleize(word) ⇒ Object
Capitalizes all the words and replaces some characters in the string to create a nicer looking title.
-
#transliterate(string, replacement = "?") ⇒ Object
Replaces non-ASCII characters with an ASCII approximation, or if none exists, a replacement character which defaults to “?”.
-
#underscore(camel_cased_word) ⇒ Object
Makes an underscored, lowercase form from the expression in the string.
Instance Method Details
#camelize(term, uppercase_first_letter = true) ⇒ Object
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.
Examples:
"active_record".camelize # => "ActiveRecord"
"active_record".camelize(:lower) # => "activeRecord"
"active_record/errors".camelize # => "ActiveRecord::Errors"
"active_record/errors".camelize(:lower) # => "activeRecord::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"
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# File 'lib/active_support/inflector/methods.rb', line 54 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 |
#classify(table_name) ⇒ Object
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"
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# File 'lib/active_support/inflector/methods.rb', line 136 def classify(table_name) # strip out any leading schema name camelize(singularize(table_name.to_s.sub(/.*\./, ''))) end |
#constantize(camel_cased_word) ⇒ Object
:nodoc:
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# File 'lib/active_support/inflector/methods.rb', line 209 def constantize(camel_cased_word) names = camel_cased_word.split('::') names.shift if names.empty? || names.first.empty? constant = Object names.each do |name| constant = constant.const_defined?(name) ? constant.const_get(name) : constant.const_missing(name) end constant end |
#dasherize(underscored_word) ⇒ Object
Replaces underscores with dashes in the string.
Example:
"puni_puni" # => "puni-puni"
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# File 'lib/active_support/inflector/methods.rb', line 145 def dasherize(underscored_word) underscored_word.gsub(/_/, '-') end |
#deconstantize(path) ⇒ Object
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
.
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# File 'lib/active_support/inflector/methods.rb', line 173 def deconstantize(path) path.to_s[0...(path.rindex('::') || 0)] # implementation based on the one in facets' Module#spacename end |
#demodulize(path) ⇒ Object
Removes the module part from the expression in the string:
"ActiveRecord::CoreExtensions::String::Inflections".demodulize # => "Inflections"
"Inflections".demodulize # => "Inflections"
See also deconstantize
.
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# File 'lib/active_support/inflector/methods.rb', line 155 def demodulize(path) path = path.to_s if i = path.rindex('::') path[(i+2)..-1] else path end end |
#foreign_key(class_name, separate_class_name_and_id_with_underscore = true) ⇒ Object
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"
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# File 'lib/active_support/inflector/methods.rb', line 185 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 |
#humanize(lower_case_and_underscored_word) ⇒ Object
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"
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# File 'lib/active_support/inflector/methods.rb', line 93 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$/, "") result.gsub(/(_)?([a-z\d]*)/i) { "#{$1 && ' '}#{inflections.acronyms[$2] || $2.downcase}" }.gsub(/^\w/) { $&.upcase } end |
#inflections ⇒ Object
Yields a singleton instance of Inflector::Inflections so you can specify additional inflector rules.
Example:
ActiveSupport::Inflector.inflections do |inflect|
inflect.uncountable "rails"
end
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# File 'lib/active_support/inflector/inflections.rb', line 164 def inflections if block_given? yield Inflections.instance else Inflections.instance end end |
#ordinalize(number) ⇒ Object
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"
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# File 'lib/active_support/inflector/methods.rb', line 275 def ordinalize(number) if (11..13).include?(number.to_i.abs % 100) "#{number}th" else case number.to_i.abs % 10 when 1; "#{number}st" when 2; "#{number}nd" when 3; "#{number}rd" else "#{number}th" end end end |
#parameterize(string, sep = '-') ⇒ Object
Replaces special characters in a string so that it may be used as part of a ‘pretty’ URL.
Examples
class Person
def to_param
"#{id}-#{name.parameterize}"
end
end
@person = Person.find(1)
# => #<Person id: 1, name: "Donald E. Knuth">
<%= link_to(@person.name, person_path(@person)) %>
# => <a href="/person/1-donald-e-knuth">Donald E. Knuth</a>
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# File 'lib/active_support/inflector/transliterate.rb', line 82 def parameterize(string, sep = '-') # replace accented chars with their ascii equivalents parameterized_string = transliterate(string) # Turn unwanted chars into the separator parameterized_string.gsub!(/[^a-z0-9\-_]+/i, sep) unless sep.nil? || sep.empty? re_sep = Regexp.escape(sep) # No more than one of the separator in a row. parameterized_string.gsub!(/#{re_sep}{2,}/, sep) # Remove leading/trailing separator. parameterized_string.gsub!(/^#{re_sep}|#{re_sep}$/i, '') end parameterized_string.downcase end |
#pluralize(word) ⇒ Object
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"
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# File 'lib/active_support/inflector/methods.rb', line 23 def pluralize(word) apply_inflections(word, inflections.plurals) end |
#safe_constantize(camel_cased_word) ⇒ Object
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
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# File 'lib/active_support/inflector/methods.rb', line 254 def safe_constantize(camel_cased_word) begin constantize(camel_cased_word) rescue NameError => e raise unless e. =~ /uninitialized constant #{const_regexp(camel_cased_word)}$/ || e.name.to_s == camel_cased_word.to_s rescue ArgumentError => e raise unless e. =~ /not missing constant #{const_regexp(camel_cased_word)}\!$/ end end |
#singularize(word) ⇒ Object
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"
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# File 'lib/active_support/inflector/methods.rb', line 35 def singularize(word) apply_inflections(word, inflections.singulars) end |
#tableize(class_name) ⇒ Object
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"
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# File 'lib/active_support/inflector/methods.rb', line 122 def tableize(class_name) pluralize(underscore(class_name)) end |
#titleize(word) ⇒ Object
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"
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# File 'lib/active_support/inflector/methods.rb', line 111 def titleize(word) humanize(underscore(word)).gsub(/\b('?[a-z])/) { $1.capitalize } end |
#transliterate(string, replacement = "?") ⇒ Object
Replaces non-ASCII characters with an ASCII approximation, or if none exists, a replacement character which defaults to “?”.
transliterate("Ærøskøbing")
# => "AEroskobing"
Default approximations are provided for Western/Latin characters, e.g, “ø”, “ñ”, “é”, “ß”, etc.
This method is I18n aware, so you can set up custom approximations for a locale. This can be useful, for example, to transliterate German’s “ü” and “ö” to “ue” and “oe”, or to add support for transliterating Russian to ASCII.
In order to make your custom transliterations available, you must set them as the i18n.transliterate.rule
i18n key:
# Store the transliterations in locales/de.yml
i18n:
transliterate:
rule:
ü: "ue"
ö: "oe"
# Or set them using Ruby
I18n.backend.store_translations(:de, :i18n => {
:transliterate => {
:rule => {
"ü" => "ue",
"ö" => "oe"
}
}
})
The value for i18n.transliterate.rule
can be a simple Hash that maps characters to ASCII approximations as shown above, or, for more complex requirements, a Proc:
I18n.backend.store_translations(:de, :i18n => {
:transliterate => {
:rule => lambda {|string| MyTransliterator.transliterate(string)}
}
})
Now you can have different transliterations for each locale:
I18n.locale = :en
transliterate("Jürgen")
# => "Jurgen"
I18n.locale = :de
transliterate("Jürgen")
# => "Juergen"
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# File 'lib/active_support/inflector/transliterate.rb', line 61 def transliterate(string, replacement = "?") I18n.transliterate(ActiveSupport::Multibyte::Unicode.normalize( ActiveSupport::Multibyte::Unicode.tidy_bytes(string), :c), :replacement => replacement) end |
#underscore(camel_cased_word) ⇒ Object
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
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"
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# File 'lib/active_support/inflector/methods.rb', line 76 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 |