graphql-dotnet Enum value naming convention for HotChocolate

NamingConventions.cs

/// <summary>
/// Custom naming conventions. 
/// 
/// Usage in v10:
/// <c>services.AddSingleton&lt;INamingConventions, NamingConventions&gt;()</c>
/// <c>IRequestExecutorBuilder.AddConvention<INamingConventions>(new NamingConventions())</c>
/// Usage in v11:
/// 
/// </summary>
public class NamingConventions : DefaultNamingConventions
{
    /// <summary>
    /// Gets the enum value name for the graph enum definition.
    /// Overrides the default by using the same naming convention graphql-dotnet was using,
    /// e.g. SOME_ENUM_VALUE, rather than SOMEENUMVALUE.
    /// </summary>
    /// <param name="value">Value to get name for.</param>
    /// <returns>Enum value name.</returns>
    public override NameString GetEnumValueName(object value)
    {
        if (value == null)
        {
            throw new ArgumentNullException(nameof(value));
        }

        // Same convention as graphql-dotnet was using, e.g. SOME_ENUM_VALUE
        // See: https://github.com/graphql-dotnet/graphql-dotnet/blob/7c00e2a9a8cc9250fcdbe012bd9b40e110f6d5ab/src/GraphQL/Utilities/StringUtils.cs#L40
        var result = "";
        var index = 0;

        foreach (Match match in _reWords.Matches(value.ToString()))
        {
            result += (index == 0 ? "" : "_") + match!.Value.ToUpperInvariant();
            index++;
        }

        return result;
    }

    private static readonly Regex _reWords = new Regex(@"[A-Z\xc0-\xd6\xd8-\xde]?[a-z\xdf-\xf6\xf8-\xff]+(?:['’](?:d|ll|m|re|s|t|ve))?(?=[\xac\xb1\xd7\xf7\x00-\x2f\x3a-\x40\x5b-\x60\x7b-\xbf\u2000-\u206f \t\x0b\f\xa0\ufeff\n\r\u2028\u2029\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000]|[A-Z\xc0-\xd6\xd8-\xde]|$)|(?:[A-Z\xc0-\xd6\xd8-\xde]|[^\ud800-\udfff\xac\xb1\xd7\xf7\x00-\x2f\x3a-\x40\x5b-\x60\x7b-\xbf\u2000-\u206f \t\x0b\f\xa0\ufeff\n\r\u2028\u2029\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000\d+\u2700-\u27bfa-z\xdf-\xf6\xf8-\xffA-Z\xc0-\xd6\xd8-\xde])+(?:['’](?:D|LL|M|RE|S|T|VE))?(?=[\xac\xb1\xd7\xf7\x00-\x2f\x3a-\x40\x5b-\x60\x7b-\xbf\u2000-\u206f \t\x0b\f\xa0\ufeff\n\r\u2028\u2029\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000]|[A-Z\xc0-\xd6\xd8-\xde](?:[a-z\xdf-\xf6\xf8-\xff]|[^\ud800-\udfff\xac\xb1\xd7\xf7\x00-\x2f\x3a-\x40\x5b-\x60\x7b-\xbf\u2000-\u206f \t\x0b\f\xa0\ufeff\n\r\u2028\u2029\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000\d+\u2700-\u27bfa-z\xdf-\xf6\xf8-\xffA-Z\xc0-\xd6\xd8-\xde])|$)|[A-Z\xc0-\xd6\xd8-\xde]?(?:[a-z\xdf-\xf6\xf8-\xff]|[^\ud800-\udfff\xac\xb1\xd7\xf7\x00-\x2f\x3a-\x40\x5b-\x60\x7b-\xbf\u2000-\u206f \t\x0b\f\xa0\ufeff\n\r\u2028\u2029\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000\d+\u2700-\u27bfa-z\xdf-\xf6\xf8-\xffA-Z\xc0-\xd6\xd8-\xde])+(?:['’](?:d|ll|m|re|s|t|ve))?|[A-Z\xc0-\xd6\xd8-\xde]+(?:['’](?:D|LL|M|RE|S|T|VE))?|\d+|(?:[\u2700-\u27bf]|(?:\ud83c[\udde6-\uddff]){2}|[\ud800-\udbff][\udc00-\udfff])[\ufe0e\ufe0f]?(?:[\u0300-\u036f\ufe20-\ufe23\u20d0-\u20f0]|\ud83c[\udffb-\udfff])?(?:\u200d(?:[^\ud800-\udfff]|(?:\ud83c[\udde6-\uddff]){2}|[\ud800-\udbff][\udc00-\udfff])[\ufe0e\ufe0f]?(?:[\u0300-\u036f\ufe20-\ufe23\u20d0-\u20f0]|\ud83c[\udffb-\udfff])?)*");
}