What’s the best way to play with F# that feels natural for a Python programmer?

I really like having my screen split down the middle (tmux), with code on the left (“vim code/“) and program output on the right (“watch-exec code/ — python -mcode”).

Every time I change a file in code/, watch-exec runs the program again.

Doing this with dotnet run seems to take a full 2 to 4 seconds to run though, which seems pretty heavyweight. It’s obviously not the best way to interactively edit a file of code. What is?