Module: RailsStats::Inflector

Extended by:
Inflector
Included in:
Inflector
Defined in:
lib/rails_stats/inflector.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 or wish to define rules for languages other than English, please correct or add them yourself (explained below).

Defined Under Namespace

Classes: Inflections

Instance Method Summary collapse

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.

'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"


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# 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

#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).

'egg_and_hams'.classify # => "EggAndHam"
'posts'.classify        # => "Post"

Singular names are not handled correctly:

'business'.classify     # => "Busines"


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# 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

#constantize(camel_cased_word) ⇒ Object

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.



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# 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

#dasherize(underscored_word) ⇒ Object

Replaces underscores with dashes in the string.

'puni_puni'.dasherize # => "puni-puni"


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# File 'lib/rails_stats/inflector.rb', line 360

def dasherize(underscored_word)
  underscored_word.tr('_', '-')
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/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

#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/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

#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'.

'Message'.foreign_key        # => "message_id"
'Message'.foreign_key(false) # => "messageid"
'Admin::Post'.foreign_key    # => "post_id"


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# 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

#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.

'employee_salary'.humanize # => "Employee salary"
'author_id'.humanize       # => "Author"


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# 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

#inflections(locale = :en) ⇒ Object

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


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# 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

#ordinal(number) ⇒ Object

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"


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# 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

#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.

ordinalize(1)     # => "1st"
ordinalize(2)     # => "2nd"
ordinalize(1002)  # => "1002nd"
ordinalize(1003)  # => "1003rd"
ordinalize(-11)   # => "-11th"
ordinalize(-1021) # => "-1021st"


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# File 'lib/rails_stats/inflector.rb', line 511

def ordinalize(number)
  "#{number}#{ordinal(number)}"
end

#pluralize(word, locale = :en) ⇒ Object

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"


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# File 'lib/rails_stats/inflector.rb', line 233

def pluralize(word, locale = :en)
  apply_inflections(word, inflections(locale).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/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

#singularize(word, locale = :en) ⇒ Object

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"


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# File 'lib/rails_stats/inflector.rb', line 250

def singularize(word, locale = :en)
  apply_inflections(word, inflections(locale).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.

'RawScaledScorer'.tableize # => "raw_scaled_scorers"
'egg_and_ham'.tableize     # => "egg_and_hams"
'fancyCategory'.tableize   # => "fancy_categories"


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# File 'lib/rails_stats/inflector.rb', line 338

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 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"


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# File 'lib/rails_stats/inflector.rb', line 328

def titleize(word)
  humanize(underscore(word)).gsub(/\b(?<!['’`])[a-z]/) { $&.capitalize }
end

#underscore(camel_cased_word) ⇒ Object

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"


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# 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