How to map a shell command in the lua nvim config?

Question

How to map a shell command in the lua nvim config?

maps.n["<F4>"] = { function() io.popen("python3 " + vim.fn.expand("%")) end, desc = "Run current Python file"}

Error:

E5108: Error executing lua: /home/kobe/.config/nvim/lua/core/mappings.lua:19: attempt to perform arithmetic on a string value                                                                               
stack traceback:
        /home/kobe/.config/nvim/lua/core/mappings.lua:19: in function </home/kobe/.config/nvim/lua/core/mappings.lua:19>

Answer 1

Maybe this isn't exactly what you're looking for, but I use plugins like toggleterm for this. You can setup keymappings to run whatever shell command or program you want, and also have it show up in a floating or none-floating window, too.

As for just mapping it without any plugins and having the command be executing, I'm not entirely sure.

Answer 2

In Lua, operand to concatenate 2 strings is .. not + as in Python.

Correct your code: function() io.popen("python3 ".. vim.fn.expand("%")) end