jupiter.lua

--write a (non-serial) table to a file. The filename should be a property of "data": data._fileName = "*.extn"
local jupiter = {saveDir = "save"}

jupiter.save = function(data)
	assert(type(data) == "table", "Tables must be provided to saveFile!")
	if not love.filesystem.getInfo(jupiter.saveDir) == "directory" then assert(love.filesystem.createDirectory(jupiter.saveDir), "Unable to create save directory in " .. love.filesystem.getSaveDirectory() .. "!") end --make the save folder if required
	local file = love.filesystem.newFile(jupiter.saveDir .. "/" .. data._fileName)
	file:open("w")

	local function serial(table, scope)
		scope = scope or ""
		for k, v in pairs(table) do
			if k ~= "_fileName" then
				if type(v) == "table" then
					serial(v, scope .. tostring(k) .. ".")
				else
					local x = file:write(scope .. k .. "=" .. tostring(v) .. "\n") --write value
					if not x then return nil end
				end
			end
		end
	end

	serial(data)

	return true
end

--load a file. If no specific file is given it returns the latest save file
jupiter.load = function(name)

	if not love.filesystem.getInfo(jupiter.saveDir) == "directory" then assert(love.filesystem.createDirectory(jupiter.saveDir), "Unable to create save directory in " .. love.filesystem.getSaveDirectory() .. "!") end
	--load the latest save file if no file is given (useful for 'continue' option)
	if not name then
		local saveFiles = love.filesystem.getDirectoryItems(jupiter.saveDir)
		local orderedFiles = {}
		for k, file in ipairs(saveFiles) do
			--ignore files such as .DS_Store
			if not (file:sub(1, 1) == ".") and file:match("%.save$") then
				table.insert(orderedFiles, {f = file, t = love.filesystem.getInfo(jupiter.saveDir .. "/" .. file).modtime or 0})
			end
		end
		if # orderedFiles ~= 0 then
			--sort the files in modified order
			table.sort(orderedFiles, function(a, b) return a.t > b.t end)
			name = orderedFiles[1].f
		end
	end
	--don't do anything if there are no saves
	if name then
		if love.filesystem.getInfo(jupiter.saveDir .. "/" .. name) and love.filesystem.getInfo(jupiter.saveDir .. "/" .. name).type == "file" then
			local saveFile = {} --data from the file
			local pointer
			--find tables
			local function deserial(value)
				pointer = saveFile
				local scope, dotCount = value:gsub("%.", "%1")
				for x = 1, dotCount do
					local element = scope:match("^(..-)%.") --get the leftmost index
					scope = scope:match("^" .. element .. "%.(.+)") --trim the current index for the next iteration
					element = tonumber(element) and tonumber(element) or element
					pointer[element] = not pointer[element] and {} or pointer[element] --create the table if needed
					pointer = pointer[element] --set the pointer to the current level
				end
				return scope
			end

			--load the data
			for l in love.filesystem.lines(jupiter.saveDir .. "/" .. name) do
				local k, v = l:match("^(..-)=(.+)$")
				if k and v then
					local index = deserial(k)
					if v ~= "nil" and v ~= "false" then --ignore nil values that may have been set by the player
						index = tonumber(index) and tonumber(index) or index
						pointer[index] = tonumber(v) and tonumber(v) or v
					end
				end
			end
			saveFile._fileName = name
			return saveFile
		end
	end
end

return jupiter