How can I execute Lua code from a buffer?

Question

I realized that for a very basic lua debugging the most simple way is to write directly the code in the command line (no plugin, no DAP).

For example:

:lua print(vim.inspect(vim.api.nvim_list_wins()))

But debugging/tests would be much more convenient if I could have something like the command line in a dedicated window.

Is that possible?

Answer 1

The :%lua command executes all the lines of the buffer using the lua Neovim interpreter.

The :'<,'>lua command executes the selected line of the buffer using the lua Neovim interpreter.

For making tests:

• I create an empty buffer (optionally I set its filetype to lua to get the lua colorization).
• I type my commands
• I select the ones that I would like to execute
• I hit: :lua that execute :'<,'>lua and pass the lines to the Neovim interpreter.

e.g.: If you have a buffer with the following three lines:

print("top")
n = 4
print("foo " .. tostring(n))

If you select the second and third line and hit :lua you'll get:

foo 4 

Answer 2

This is not as sophisticated as using :[range]source/:[range]lua, but you can open a command-line window using q: (or :Ctrl+f).

Why is it less sophisticated? You can't enter multi-line commands (though | still works). Plus, the advantage of a dedicated buffer as in other answers is that you can write it out to a file somewhere and keep using it later.

Answer 3

You can write Vimscript (including the :lua command) in any buffer. You can then either source the whole buffer with :source or prefix a range, e.g. :.source will work on the current line.

This way, you can develop your code and run it. When you're done you can write the buffer to a file.

See :help :source for reference.