Sharing variables between languages

When I first tried Polyglot Notebooks, I had an immediate thought to try to work directly with an F# variable from C# code.

Let’s try that now by adding a new code cell and changing its language to C#. Next, add a line of code attempting to reference the maxNum variable:

Console.WriteLine($"The value in maxNum is {maxNum}");

When you run this, you should see a “red squiggly line” under maxNum and get a CS0103 compiler error below your cell, as shown in Figure 2.20:

Figure 2.20 – A compiler error shown in the notebook

As we saw earlier, maxNum is available in the Variables view, so what’s going on?

It turns out that each language has its own kernel that is part of .NET Interactive. This means that your C# variables are kept in a separate area from your F# variables, and so on for other languages.

Effectively, your C# code cannot reference F# variables and vice...