https://github.com/wiremod/wire/issues/1179

file_DeleteDir.lua

-- Localization of used libraries/functions, as an access to local (upvalues) is faster than global.
local file = file
local file_Delete, file_Find = file.Delete, file.Find

local file_DeleteDir  -- Separate declaration from definition (since it is a recursive function).

--- A function to recursively remove/delete files and sub-directories.
--- gate_folder_name: Name of the folder for the Editor mode (e.g. expression2).
--- selected_folder_path: Directory (relative to gate_folder_name) to be deleted/removed.
file_DeleteDir = function(gate_folder_name, selected_folder_path)
	if not isstring(gate_folder_name) or not isstring(selected_folder_path) or gate_folder_name:len() < 1 or selected_folder_path:len() < 1 or gate_folder_name == "/" or selected_folder_path == "/" then return end  -- Avoid errors and removing/deleting everything from gate's folder (don't display an option on the root/gate folder).
	local path = ((gate_folder_name:sub(-1) == "/" and gate_folder_name) or (gate_folder_name .. "/")) .. ((selected_folder_path:sub(-1) == "/" and selected_folder_path) or (selected_folder_path .. "/"))  -- Make sure both arguments end with '/' character.
	local found_files, found_directories = file_Find(path .. "*", "DATA")  -- Search for files and folders in selected path.
	for _, file_name in next, found_files do
		if file_name:sub(-4):upper() == ".TXT" then  -- Security measure, only process files with '.txt' (text file) extension.
			file_Delete(path .. file_name)  -- First, remove/delete files from directory (it is automatically relative to DATA folder).
		end
	end
	for _, directory_name in next, found_directories do
		if directory_name ~= '..' then  -- Another security measure (skip the hardlink to the parent directory).
			file_DeleteDir(gate_folder_name, selected_folder_path .. "/" .. directory_name)  -- Second, call this function recursively to remove/delete all files and sub-directories.
		end
	end
	return file_Delete(path:sub(1, -2))  -- Finally, try to remove/delete (empty) directory.
end

file_DeleteDir("expression2", "path/to/lib") -- Given the correct path. In this case, it would remove/delete all files and sub-directories from "expression2/path/to/lib" directory.
file_DeleteDir("expression2/", "path/to/lib/") -- Same as above, it shows that the function will still work even with trailing '/' character (in either of the two arguments).
	
-- The following won't work (at least it is not supposed to be called like so):
file_DeleteDir("/", "")
file_DeleteDir()