A singleton instance of this class is yielded by Inflector.inflections, which can then be used to specify additional inflection rules. Examples: 

  ActiveSupport::Inflector.inflections do |inflect|
    inflect.plural /^(ox)$/i, '\1\2en'
    inflect.singular /^(ox)en/i, '\1'

    inflect.irregular 'octopus', 'octopi'

    inflect.uncountable "equipment"
  end

New rules are added at the top. So in the example above, the irregular rule for octopus will now be the first of the pluralization and singularization rules that is runs. This guarantees that your rules run before any of the rules that may already have been loaded.

Methods
Included Modules
Attributes
[R] humans
[R] plurals
[R] singulars
[R] uncountables
Public Class methods
new()

[ show source ]

    # File activesupport/lib/active_support/inflector.rb, line 38
38:       def initialize
39:         @plurals, @singulars, @uncountables, @humans = [], [], [], []
40:       end
Public Instance methods
clear(scope = :all)

Clears the loaded inflections within a given scope (default is :all). Give the scope as a symbol of the inflection type, the options are: :plurals, :singulars, :uncountables, :humans.

Examples: 

  clear :all
  clear :plurals

[ show source ]

     # File activesupport/lib/active_support/inflector.rb, line 106
106:       def clear(scope = :all)
107:         case scope
108:           when :all
109:             @plurals, @singulars, @uncountables = [], [], []
110:           else
111:             instance_variable_set "@#{scope}", []
112:         end
113:       end
human(rule, replacement)

Specifies a humanized form of a string by a regular expression rule or by a string mapping. When using a regular expression based replacement, the normal humanize formatting is called after the replacement. When a string is used, the human form should be specified as desired (example: ‘The name’, not ‘the_name’)

Examples: 

  human /_cnt$/i, '\1_count'
  human "legacy_col_person_name", "Name"

[ show source ]

    # File activesupport/lib/active_support/inflector.rb, line 95
95:       def human(rule, replacement)
96:         @humans.insert(0, [rule, replacement])
97:       end
irregular(singular, plural)

Specifies a new irregular that applies to both pluralization and singularization at the same time. This can only be used for strings, not regular expressions. You simply pass the irregular in singular and plural form.

Examples: 

  irregular 'octopus', 'octopi'
  irregular 'person', 'people'

[ show source ]

    # File activesupport/lib/active_support/inflector.rb, line 64
64:       def irregular(singular, plural)
65:         @uncountables.delete(singular)
66:         @uncountables.delete(plural)
67:         if singular[0,1].upcase == plural[0,1].upcase
68:           plural(Regexp.new("(#{singular[0,1]})#{singular[1..-1]}$", "i"), '\1' + plural[1..-1])
69:           singular(Regexp.new("(#{plural[0,1]})#{plural[1..-1]}$", "i"), '\1' + singular[1..-1])
70:         else
71:           plural(Regexp.new("#{singular[0,1].upcase}(?i)#{singular[1..-1]}$"), plural[0,1].upcase + plural[1..-1])
72:           plural(Regexp.new("#{singular[0,1].downcase}(?i)#{singular[1..-1]}$"), plural[0,1].downcase + plural[1..-1])
73:           singular(Regexp.new("#{plural[0,1].upcase}(?i)#{plural[1..-1]}$"), singular[0,1].upcase + singular[1..-1])
74:           singular(Regexp.new("#{plural[0,1].downcase}(?i)#{plural[1..-1]}$"), singular[0,1].downcase + singular[1..-1])
75:         end
76:       end
plural(rule, replacement)

Specifies a new pluralization rule and its replacement. The rule can either be a string or a regular expression. The replacement should always be a string that may include references to the matched data from the rule.

[ show source ]

    # File activesupport/lib/active_support/inflector.rb, line 44
44:       def plural(rule, replacement)
45:         @uncountables.delete(rule) if rule.is_a?(String)
46:         @uncountables.delete(replacement)
47:         @plurals.insert(0, [rule, replacement])
48:       end
singular(rule, replacement)

Specifies a new singularization rule and its replacement. The rule can either be a string or a regular expression. The replacement should always be a string that may include references to the matched data from the rule.

[ show source ]

    # File activesupport/lib/active_support/inflector.rb, line 52
52:       def singular(rule, replacement)
53:         @uncountables.delete(rule) if rule.is_a?(String)
54:         @uncountables.delete(replacement)
55:         @singulars.insert(0, [rule, replacement])
56:       end
uncountable(*words)

Add uncountable words that shouldn‘t be attempted inflected.

Examples: 

  uncountable "money"
  uncountable "money", "information"
  uncountable %w( money information rice )

[ show source ]

    # File activesupport/lib/active_support/inflector.rb, line 84
84:       def uncountable(*words)
85:         (@uncountables << words).flatten!
86:       end