/lib/utilities/inflect.rb

# Much love to Facets (more specifically English) for this module
# http://english.rubyforge.org/
# changed slightly in the hopes of one day implementing a different set
# of rules for different languages
# NOTE: this is NOT implemented yet.
# plural and singular work directly with the English class

module Inflect
  module InflectorMethods
    
    # Define a general exception.
    def word(singular, plural=nil)
      plural = singular unless plural
      singular_word(singular, plural)
      plural_word(singular, plural)
    end

    # Define a singularization exception.
    def singular_word(singular, plural)
      @singular_of[plural] = singular
    end

    # Define a pluralization exception.
    def plural_word(singular, plural)
      @plural_of[singular] = plural
    end

    # Define a general rule.
    def rule(singular, plural)
      singular_rule(singular, plural)
      plural_rule(singular, plural)
    end

    # Define a singularization rule.
    def singular_rule(singular, plural)
      @singular_rules << [singular, plural]
    end

    # Define a plurualization rule.
    def plural_rule(singular, plural)
      @plural_rules << [singular, plural]
    end

    # Read prepared singularization rules.
    def singularization_rules
      return @singularization_rules if @singularization_rules
      sorted = @singular_rules.sort_by{ |s, p| "#{p}".size }.reverse
      @singularization_rules = sorted.collect do |s, p|
        [ /#{p}$/, "#{s}" ]
      end
    end

    # Read prepared pluralization rules.
    def pluralization_rules
      return @pluralization_rules if @pluralization_rules
      sorted = @plural_rules.sort_by{ |s, p| "#{s}".size }.reverse
      @pluralization_rules = sorted.collect do |s, p|
        [ /#{s}$/, "#{p}" ]
      end
    end

    #
    def plural_of
      @plural_of
    end

    #
    def singular_of
      @singular_of
    end

    # Convert an English word from plurel to singular.
    #
    #   "boys".singular      #=> boy
    #   "tomatoes".singular  #=> tomato
    #
    def singular(word)
      if result = singular_of[word]
        return result.dup
      end
      result = word.dup
      singularization_rules.each do |(match, replacement)|
        break if result.gsub!(match, replacement)
      end
      return result
    end

    # Convert an English word from singular to plurel.
    #
    #   "boy".plural     #=> boys
    #   "tomato".plural  #=> tomatoes
    #
    def plural(word)
      if result = plural_of[word]
        return result.dup
      end
      #return self.dup if /s$/ =~ self # ???
      result = word.dup
      pluralization_rules.each do |(match, replacement)|
        break if result.gsub!(match, replacement)
      end
      return result
    end
  end

  class English
    @singular_of = {}
    @plural_of = {}
    
    @singular_rules = []
    @plural_rules = []
    
    class << self
      include InflectorMethods
    end

    # One argument means singular and plural are the same.
    word 'equipment'
    word 'information'
    word 'money'
    word 'species'
    word 'series'
    word 'fish'
    word 'sheep'
    word 'moose'
    word 'hovercraft'

    # Two arguments defines a singular and plural exception.
    word 'Swiss'     , 'Swiss'
    word 'life'      , 'lives'
    word 'wife'      , 'wives'
    word 'virus'     , 'viri'
    word 'octopus'   , 'octopi'
    word 'cactus'    , 'cacti'
    word 'goose'     , 'geese'
    word 'criterion' , 'criteria'
    word 'alias'     , 'aliases'
    word 'status'    , 'statuses'
    word 'axis'      , 'axes'
    word 'crisis'    , 'crises'
    word 'testis'    , 'testes'
    word 'child'     , 'children'
    word 'person'    , 'people'
    word 'potato'    , 'potatoes'
    word 'tomato'    , 'tomatoes'
    word 'buffalo'   , 'buffaloes'
    word 'torpedo'   , 'torpedoes'
    word 'quiz'      , 'quizes'
    word 'matrix'    , 'matrices'
    word 'vertex'    , 'vetices'
    word 'index'     , 'indices'
    word 'ox'        , 'oxen'
    word 'mouse'     , 'mice'
    word 'louse'     , 'lice'
    word 'thesis'    , 'theses'
    word 'thief'     , 'thieves'
    word 'analysis'  , 'analyses'

    # One-way singularization exception (convert plural to singular).
    singular_word 'cactus', 'cacti'

    # General rules.
    rule 'hive' , 'hives'
    rule 'rf'   , 'rves'
    rule 'af'   , 'aves'
    rule 'ero'  , 'eroes'
    rule 'man'  , 'men'
    rule 'ch'   , 'ches'
    rule 'sh'   , 'shes'
    rule 'ss'   , 'sses'
    rule 'ta'   , 'tum'
    rule 'ia'   , 'ium'
    rule 'ra'   , 'rum'
    rule 'ay'   , 'ays'
    rule 'ey'   , 'eys'
    rule 'oy'   , 'oys'
    rule 'uy'   , 'uys'
    rule 'y'    , 'ies'
    rule 'x'    , 'xes'
    rule 'lf'   , 'lves'
    rule 'us'   , 'uses'
    rule ''     , 's'

    # One-way singular rules.
    singular_rule 'of' , 'ofs' # proof
    singular_rule 'o'  , 'oes' # hero, heroes
    singular_rule 'f'  , 'ves'

    # One-way plural rules.
    plural_rule 'fe' , 'ves' # safe, wife
    plural_rule 's'  , 'ses'
  end
end