Clever way to append 's' for plural form in .Net (syntactic sugar)

Question

I want to be able to type something like:

Console.WriteLine(\"You have {0:life/lives} left.\", player.Lives);

instead of

Consol         


        

Answer 1

See the Inflector class that is part of Castle ActiveRecord. It is licensed under the Apache license.

It has a set of regular expression rules that define how words are pluralized. The version I have used has some errors in these rules though, e.g. it has a 'virus' → 'virii' rule.

I have three extension methods which wrap Inflector, the first of which may be right up your street:

    /// <summary>
    /// Pluralises the singular form word specified.
    /// </summary>
    /// <param name="this">The singular form.</param>
    /// <param name="count">The count.</param>
    /// <returns>The word, pluralised if necessary.</returns>
    public static string Pluralise(this string @this, long count)
    {
        return (count == 1) ? @this :
                              Pluralise(@this);
    }

    /// <summary>
    /// Pluralises the singular form word specified.
    /// </summary>
    /// <param name="this">The singular form word.</param>
    /// <returns>The plural form.</returns>
    public static string Pluralise(this string @this)
    {
        return Inflector.Pluralize(@this);
    }

    /// <summary>
    /// Singularises the plural form word.
    /// </summary>
    /// <param name="this">The plural form word.</param>
    /// <returns>Th singular form.</returns>
    public static string Singularise(this string @this)
    {
        return Inflector.Singularize(@this);
    }

Answer 2

You can create a custom formatter that does that:

public class PluralFormatProvider : IFormatProvider, ICustomFormatter {

  public object GetFormat(Type formatType) {
    return this;
  }


  public string Format(string format, object arg, IFormatProvider formatProvider) {
    string[] forms = format.Split(';');
    int value = (int)arg;
    int form = value == 1 ? 0 : 1;
    return value.ToString() + " " + forms[form];
  }

}

The Console.WriteLine method has no overload that takes a custom formatter, so you have to use String.Format:

Console.WriteLine(String.Format(
  new PluralFormatProvider(),
  "You have {0:life;lives} left, {1:apple;apples} and {2:eye;eyes}.",
  1, 0, 2)
);

Output:

You have 1 life left, 0 apples and 2 eyes.

Note: This is the bare minimum to make a formatter work, so it doesn't handle any other formats or data types. Ideally it would detect the format and data type, and pass the formatting on to a default formatter if there is some other formatting or data types in the string.