rails--rails/activesupport/lib/active_support/inflections.rb

module ActiveSupport
  Inflector.inflections do |inflect|
    inflect.plural(/$/, 's')
    inflect.plural(/s$/i, 's')
    inflect.plural(/(ax|test)is$/i, '\1es')
    inflect.plural(/(octop|vir)us$/i, '\1i')
    inflect.plural(/(alias|status)$/i, '\1es')
    inflect.plural(/(bu)s$/i, '\1ses')
    inflect.plural(/(buffal|tomat)o$/i, '\1oes')
    inflect.plural(/([ti])um$/i, '\1a')
    inflect.plural(/sis$/i, 'ses')
    inflect.plural(/(?:([^f])fe|([lr])f)$/i, '\1\2ves')
    inflect.plural(/(hive)$/i, '\1s')
    inflect.plural(/([^aeiouy]|qu)y$/i, '\1ies')
    inflect.plural(/(x|ch|ss|sh)$/i, '\1es')
    inflect.plural(/(matr|vert|ind)(?:ix|ex)$/i, '\1ices')
    inflect.plural(/([m|l])ouse$/i, '\1ice')
    inflect.plural(/^(ox)$/i, '\1en')
    inflect.plural(/(quiz)$/i, '\1zes')

    inflect.singular(/s$/i, '')
    inflect.singular(/(n)ews$/i, '\1ews')
    inflect.singular(/([ti])a$/i, '\1um')
    inflect.singular(/((a)naly|(b)a|(d)iagno|(p)arenthe|(p)rogno|(s)ynop|(t)he)ses$/i, '\1\2sis')
    inflect.singular(/(^analy)ses$/i, '\1sis')
    inflect.singular(/([^f])ves$/i, '\1fe')
    inflect.singular(/(hive)s$/i, '\1')
    inflect.singular(/(tive)s$/i, '\1')
    inflect.singular(/([lr])ves$/i, '\1f')
    inflect.singular(/([^aeiouy]|qu)ies$/i, '\1y')
    inflect.singular(/(s)eries$/i, '\1eries')
    inflect.singular(/(m)ovies$/i, '\1ovie')
    inflect.singular(/(x|ch|ss|sh)es$/i, '\1')
    inflect.singular(/([m|l])ice$/i, '\1ouse')
    inflect.singular(/(bus)es$/i, '\1')
    inflect.singular(/(o)es$/i, '\1')
    inflect.singular(/(shoe)s$/i, '\1')
    inflect.singular(/(cris|ax|test)es$/i, '\1is')
    inflect.singular(/(octop|vir)i$/i, '\1us')
    inflect.singular(/(alias|status)es$/i, '\1')
    inflect.singular(/^(ox)en/i, '\1')
    inflect.singular(/(vert|ind)ices$/i, '\1ex')
    inflect.singular(/(matr)ices$/i, '\1ix')
    inflect.singular(/(quiz)zes$/i, '\1')

    inflect.irregular('person', 'people')
    inflect.irregular('man', 'men')
    inflect.irregular('child', 'children')
    inflect.irregular('sex', 'sexes')
    inflect.irregular('move', 'moves')
    inflect.irregular('cow', 'kine')

    inflect.uncountable(%w(equipment information rice money species series fish sheep))
  end
end