Question

I happen to know mono’s CSharpRepl, are there emacs csharp mode that use this to run REPL in one window, and compile/run the C# code in the other window just like python mode?

Answer 1

You could just create a lisp function to call the CSharpRepl and assign a key to call it when you’re working on C# code. For example, you could put the following in your Emacs init file (assuming the CSharpRepl executable “csharp” is in your PATH):

(defun csharp-repl ()
  "Open a new side-by-side window and start CSharpRepl in it."
  (interactive)
  (split-window-side-by-side)
  (other-window 1)
  (comint-run "csharp"))

(global-set-key [f11] 'csharp-repl)

So, if you’re editing a C# program (using whatever mode you prefer), you can now press F11 and the CSharpRepl will open up in a new window so that you can interactively evaluate C# code.