Freezer.cs

// HashSet supports collection initializer syntax
private static readonly HashSet<string> abcCollection1 = ["a", "b", "c"];
private static readonly FrozenSet<string> abcCollection2 = ["a", "b", "c"]; // doesn't work, yet...

// example with freezer:
private static readonly FrozenSet<FileAttributes> allowedAttributes = Freeze(FileAttributes.Archive, FileAttributes.Device, FileAttributes.Hidden);
private static readonly FrozenSet<string> allowedKeywords = Freeze(StringComparer.OrdinalIgnoreCase, "squirrel", "cat", "dog");

// example without:
private static readonly FrozenSet<FileAttributes> allowedAttributesUgly = new HashSet<FileAttributes>([FileAttributes.Archive, FileAttributes.Device, FileAttributes.Hidden]).ToFrozenSet();
private static readonly FrozenSet<string> allowedKeywordsUgly = new HashSet<string>(["squirrel", "cat", "dog"]).ToFrozenSet(StringComparer.OrdinalIgnoreCase);



#if NET8_0_OR_GREATER
/// <summary>
/// Provides a set of static methods for creating frozen sets with a readable syntax in field / property initialization.
/// </summary>
internal static class Freezer
{
    /// <summary>
    /// Creates a new <see cref="FrozenSet{T}"/> from the specified elements.
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="enumerable"></param>
    /// <returns></returns>
    public static FrozenSet<T> From<T>(params IEnumerable<T> enumerable)
    {
        return enumerable.ToFrozenSet();
    }

    /// <summary>
    /// Creates a new <see cref="FrozenSet{T}"/> from the specified elements.
    /// </summary> 
    public static FrozenSet<T> From<T>(IEqualityComparer<T> comparer, params IEnumerable<T> enumerable)
    {
        return enumerable.ToFrozenSet(comparer);
    }
}
#endif