My .fsx scripts are kind of old so they only work with .NET4.x, which means I need to run them with the fsharpi command in macOS.
Now I'm thinking to start migrating them to dotnet fsi; however, ideally I can find a way to run them in both ways for a while, in a transition period.
So I was hoping that, inside them, I could do some kind of conditional code like this:
#if NET5_0
System.Console.WriteLine "we're running in dotnet fsi, yay"
#else
System.Console.WriteLine "we're running with fsharpi, legacy"
#endif
But it doesn't work, surprisingly (and I say surprisingly because the define NET5_0 is being mentioned in many documentation pages). Any other idea of how I could detect this?
I think System.Environment.Version will give you the info you need:
if System.Environment.Version.Major >= 5 then
System.Console.WriteLine "we're running in dotnet fsi, yay"
else
System.Console.WriteLine "we're running with fsharpi, legacy"
It looks like NET5_0 is only defined for C#.