[Solved] Problem with love.filesystem.write and read

[Natmaz]

Hello! First time posting here. I just can't seem to figure this out myself. I already checked previous forum topics where people had a similar issue, although they're from 2014 so copying code from those topics didn't work. Looking up the documentation left me even more confused.

All I'm trying to do is save my game, and by extension load my game. I made a table called "data" in which I have all the variables that I want to be saved. My game will be a simple Tamagotchi clone of sorts, and I only have a few numbers and booleans that I want to save so far.

When I test my game, no errors appear, but I have a feeling that I did something wrong since in appData there's no LOVE folder, and one isn't creating itself no matter how much I try. I did use setIdentity but that also seems to do nothing.

Both filesystem.write and setIdentity are in love.load. I doubt it's a bug, then what am I doing wrong?

(English isn't my native language, and I'm a total begginner at programming, excuse my lack of knowledge )

[MrFariator]

Can you show your love.load in question?

[Natmaz]

I apologize if it's a bit messy and lenghty

Code: Select all

function love.load()

	love.filesystem.setIdentity('Plumgotchi')
	

--[[
	function loadGame()
		toload = love.filesystem.load("save.txt")
		toload()
	end
--]]

	love.window.setMode(500, 500, {}) -- Window size.
	love.window.setTitle('Plumgotchi') -- Window title.

	gotchiWindow.gay = love.graphics.newImage('Menus/Screen.png')
	
	data = {
	
		species = 'Common Egg',
		stage = 'Egg',
		gender = 'Egg',
		points = 0,
		money = 0,
		hunger = 4,
		mood = 4,
		eggPresent = true
	
	}
	
	function saveGame()
--		local save = data
--		love.filesystem.write("save.txt",save)
		success, message = love.filesystem.write(name, data, all)
	end
	
	eggTimer = 0
	timer = 0
	timerS = 0
	menu = 1
	hungryTimer = 0
	happyTimer = 0
	debug = true
	gotchiVisible = true
	statScreen = 1
	subMenu = false
	RNG = 0
	
	Menu1 = false
	Menu2 = false
	Menu3 = false
	Menu4 = false
	Menu5 = false
	Menu6 = false
	Menu7 = false
	Menu8 = false
	Menu9 = false
	Menu10 = false

	outerButtons = {}
	egg = {}
	child = {}
	teenager = {}
	adult = {}
	circle = {}
	heart = {}
	star = {}
	emptyStats = {}
	
	eggmax = love.filesystem.getDirectoryItems('Egg')
	childmax = love.filesystem.getDirectoryItems('Child')
	teenmax = love.filesystem.getDirectoryItems('Teenager')
	adultmax = love.filesystem.getDirectoryItems('Adult')

-- Loading images in a batch.
-- outerButtons.
	for i = 1,10 do
		outerButtons[i] = love.graphics.newImage('Menus/outer buttons/'..i..'.png')
	end

-- circle
	for i = 1,4 do
		circle[i] = love.graphics.newImage('Menus/on the screen/Hunger '..i..'.png')
	end

-- heart
	for i = 1,4 do
		heart[i] = love.graphics.newImage('Menus/on the screen/Happy '..i..'.png')
	end

-- star
	for i = 1,4 do
		star[i] = love.graphics.newImage('Menus/on the screen/Health '..i..'.png')
	end

-- emptyStats
	for i = 1,3 do
		emptyStats[i] = love.graphics.newImage('Menus/on the screen/Empty stats '..i..'.png')
	end

-- egg	
	for i = 1,#eggmax do
		egg[i] = love.graphics.newImage('Egg/Egg '..i..'.png')
	end

-- child	
	for i = 1,#childmax do
		child[i] = love.graphics.newImage('Child/Child '..i..'.png')
	end

-- teen
	for i = 1,#teenmax do
		teenager[i] = love.graphics.newImage('Teenager/Teen '..i..'.png')
	end

-- adult
	for i = 1,#adultmax	do
		adult[i] = love.graphics.newImage('Adult/Adult '..i..'.png')
	end

-- Loading sounds
	confirm = love.audio.newSource("Sfx/Select.wav", "static") -- Static for sfx, stream for music.
	moveCursor = love.audio.newSource("Sfx/Move Cursor.wav", "static")
	cancel = love.audio.newSource("Sfx/Cancel.wav", "static")


end

[zorg]

Reading the wiki's article about love.filesystem.write tells you this: data can either be a string, or a löve object; you're trying to save a table, which is basically a number.

If you don't want to use any fancy serialization libraries, then you could tiptoe the issue the following way:

Code: Select all

function serialize(t)
local s = {"return {"}
for k,v in pairs(t) do
table.insert(s, "[")
if type(k) == "string" then table.insert(s, "'") end
table.insert(s, tostring(k))
if type(k) == "string" then table.insert(s, "'") end
table.insert(s, "]")
table.insert(s, " = ")
if type(v) == "string" then table.insert(s, "'") end
table.insert(s, tostring(v))
if type(v) == "string" then table.insert(s, "'") end
table.insert(s, ", ")
end
table.insert(s, "}")
return table.concat(s)
end

This basically allows you to save a table, if it only has strings, numbers, and booleans, as either keys or values, to a file, and then you would use love.filesystem.load to load the data back as lua code, and call the chunk that function returned to get back the original values in a table.

[Natmaz]

Hmm, do I have to change anything in the function you provided? Since inserting it doesn't seem to do anything, but maybe I just don't know how to check if it works. I'm new to programming and Lua, so even with your explanation (which I appreciate a whole lot) I don't seem to know what I'm supposed to do with it.

[MrFariator]

Example usage of zorg's code (just put the serialize function somewhere where it's accessible in scope, like at the top of main.lua):

Code: Select all

local myTable = {
  myValue = 1,
  mySecondValue = 3,
  myThirdValue = 4
}

-- Serialize the table into a string with the function
local myString = serialize(myTable) -- myString is now "return {['mySecondValue'] = 3, ['myValue'] = 1, ['myThirdValue'] = 4, }"

-- Write myString into a file
love.filesystem.write( "myTestFile.txt", myString )

-- Load the file, because of the way the serialize() function formats the string it is 
-- now a function that returns the original table's contents when called.
-- This is why we add the extra parentheses to the end
local loadedValues = love.filesystem.load ( "myTestFile.txt" ) ()


print(loadedValues.myValue) -- prints 1

Do note that zorg's example function is a very basic serializer, so it won't cover all use-cases. To get around that you could, for instance, use bitser. Its usage would be something along the lines of:

Code: Select all

-- save
serializedString = bitser.dumps(tableToSave)
love.filesystem.write("myTestFile.txt", serializedString)

-- load
love.filesystem.load ("myTestFile.txt" )
someValue = bitser.loads(serializedString)

But as he said, if you don't need anything fancy with the tables you want to save, bitser isn't really necessary.

[Natmaz]

Holy heck, bitser is super easy to use and it worked for me perfectly!
Thank you very much!