rawR function that checks for required .NET framework

[tobiasko]

What about a rawR function that checks for the installed .NET framework? The C# code could be based on

 
const string subkey = @"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full\";

using (var ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey(subkey))
{
    if (ndpKey != null && ndpKey.GetValue("Release") != null)
    {
        Console.WriteLine($".NET Framework Version: {CheckFor45PlusVersion((int)ndpKey.GetValue("Release"))}");
    }
    else
    {
        Console.WriteLine(".NET Framework Version 4.5 or later is not detected.");
    }
}

// Checking the version using >= enables forward compatibility.
static string CheckFor45PlusVersion(int releaseKey)
{
    if (releaseKey >= 528040)
        return "4.8 or later";
    if (releaseKey >= 461808)
        return "4.7.2";
    if (releaseKey >= 461308)
        return "4.7.1";
    if (releaseKey >= 460798)
        return "4.7";
    if (releaseKey >= 394802)
        return "4.6.2";
    if (releaseKey >= 394254)
        return "4.6.1";
    if (releaseKey >= 393295)
        return "4.6";
    if (releaseKey >= 379893)
        return "4.5.2";
    if (releaseKey >= 378675)
        return "4.5.1";
    if (releaseKey >= 378389)
        return "4.5";
    // This code should never execute. A non-null release key should mean
    // that 4.5 or later is installed.
    return "No 4.5 or later version detected";
}

as shown here by Microsoft.

We would just need to write into a tmp file instead to the console. The R function could be something like dotNetInfo() aligned with sessionInfo() output. Or we directly check if >= 4.5.1 and return a logical, but then the function should be named is.NET() and contain a parameter named release and we would set it to 4.5.1 as default. This would also be very useful for CI, since we probably can't request specific .NET version on the test infrastructure.

What do you think, @cpanse ?