Ruby on Rails
InflectorInCSharp

    using System;
    using System.Collections;
    using System.Text.RegularExpressions;

    /// <summary>
    /// This is for pluralising and de-pluralising strings
    /// <a href="http://dev.rubyonrails.org/browser/trunk/activerecord/lib/active_record/support/inflector.rb?rev=4">http://dev.rubyonrails.org/browser/trunk/activerecord/lib/active_record/support/inflector.rb?rev=4</a>
    /// <a href="http://www.knowdotnet.com/articles/regereplacementstrings.html">http://www.knowdotnet.com/articles/regereplacementstrings.html</a>
    /// </summary>
    public class Inflector
    {
        // To ensure this is a singleton
        public static readonly Inflector Instance = new Inflector();
        private Inflector() {}
        static Inflector() { }
        private static Inflector_Rule[] Plural_Rules = new Inflector_Rule[] {
            new Inflector_Rule("(x|ch|ss)$","$1es"),                // search, switch, fix, box, process, address 
            new Inflector_Rule("([^aeiouy]|qu)y$","$1ies"),            // query, ability, agency 
            new Inflector_Rule("(?:([^f])fe|([lr])f)$","$1$2ves"),    // half, safe, wife 
            new Inflector_Rule("sis$","ses"),                        // basis, diagnosis 
            new Inflector_Rule("([ti])um$","$1a"),                    // datum, medium 
            new Inflector_Rule("person$", "people"),                // person, salesperson 
            new Inflector_Rule("man$","men"),                        // man, woman, spokesman 
            new Inflector_Rule("child$","children"),                // child 
            new Inflector_Rule("s$","s"),                            // no change (compatibility) 
            new Inflector_Rule("$","s")
            };
        public string Pluralise(string word)
        {
            foreach (Inflector_Rule rule in Plural_Rules)
            {
                if (Regex.IsMatch(word,rule.rule))
                {
                    return Regex.Replace(word,rule.rule,rule.replacement);
                }
            }
            return word + 's';
        }

    }

    class Inflector_Rule
    {
        public string rule;
        public string replacement;
        public Inflector_Rule(string Rule,string Replacement)
        {
            rule=Rule;
            replacement=Replacement;
        }
    }