https://twitter.com/jasongorman/status/951931951480475648

Simpler.cs

static class Original
{
    // Adding new extensions is simple copy/paste

    public static Int32? ConvertToInt32(this string value)
    {
        return Int32.TryParse(value, out var result) ? result : (Int32?)null;
    }

    public static Int64? ConvertToInt64(this string value)
    {
        return Int64.TryParse(value, out var result) ? result : (Int64?)null;
    }
}

static class Refactored
{
    // This isn't simple
    delegate bool TryParser<T>(string s, out T value);
    static T? Convert<T>(this string value, TryParser<T> parser) where T : struct
    {
        return parser(value, out T result) ? result : (T?)null;
    }

    // But adding new extensions is simpler copy/paste
    public static Int32? ConvertToInt32(this string value)
    {
        return value.Convert<Int32>(Int32.TryParse);
    }

    public static Int64? ConvertToInt64(this string value)
    {
        return value.Convert<Int64>(Int64.TryParse);
    }
}