How to Put Data Into a Table From an Existing File - lua

Question

I have a program for a turtle in ComputerCraft that is meant to be a storage unit. I input an item, and it should read a file to find where to put the item. If there is a new item, it adds the information to a file.
When I do
blockTypes = {}
local file = fs.open(blockTable","r")
line = file.readAll()
table.insert(blockTypes,line)
file.close()
The information gets put in as a string. This means that I can't do
print(blockTypes[1][1])
And recieve the value that would normally be in that position.
Here's my code:
blockAmount = 3
highestVal = {2,0,5}
blockTypes = {}
function addBlock()
local file = fs.open("blockTable", "a")
file.write(name)
file.write(" = {")
file.write(highestVal[1])
file.write(",")
file.write(highestVal[2])
file.write(",")
file.write(highestVal[3])
file.writeLine("};")
file.close()
end
function getBlock()
local file = fs.open("blockTable","r")
line = file.readAll()
table.insert(blockTypes,line)
file.close()
end
--This was used to test before implementing the new file system that I am trying to get to work
blockTypesOld = {
log = {2.0,0,1};
dirt = {2,0,2};
cobblestone = {2,0,3};
iron_ingot = {2,0,4};
planks = {2,0,5};
}
pos = {0,0,0}
looking = 0
function fuel()
if turtle.getFuelLevel() < 20 then
turtle.select(16)
turtle.refuel(1)
end
end
function left()
turtle.turnLeft()
looking = looking - 1
if looking < 0 then
looking = 3
end
end
function right()
turtle.turnRight()
looking = looking + 1
if looking > 3 then
looking = 0
end
end
function forward()
fuel()
if turtle.forward() then
if looking == 0 then
pos[1] = pos[1] - 1
elseif looking == 1 then
pos[3] = pos[3] - 1
elseif looking == 2 then
pos[1] = pos[1] + 1
elseif looking == 3 then
pos[3] = pos[3] + 1
else
end
end
end
function up()
fuel()
turtle.up()
pos[2] = pos[2] + 1
end
function down()
fuel()
turtle.down()
pos[2] = pos[2] - 1
end
function goHome()
while pos[3] > 0 do
while looking > 1 do
left()
end
forward()
end
while pos[2] > 0 do
down()
end
while pos[1] > 0 do
while looking > 0 do
left()
end
forward()
end
end
function goTo(a,b,c)
goHome()
while looking < 2 or looking > 2 do
right()
end
for i = pos[1],a do
forward()
end
while looking > 3 or looking < 3 do
right()
end
for i = pos[3],c do
forward()
end
for i = pos[2],b do
up()
end
while looking < 2 or looking > 2 do
left()
end
end
while true do
turtle.select(15)
while not turtle.suck() do
sleep(1)
end
itemDetails = turtle.getItemDetail()
--Finding what mod item is from and removing corresponding labels--
--EX: "minecraft:log" becomes "log"
if itemDetails.name:match("^ae2stuff:(.+)$") then
name = itemDetails.name:match("^ae2stuff:(.+)$")
elseif itemDetails.name:match("^minecraft:(.+)$") then
name = itemDetails.name:match("^minecraft:(.+)$")
elseif itemDetails.name:match("^appliedenergistics2:(.+)$") then
name = itemDetails.name:match("^appliedenergistics2:(.+)$")
elseif itemDetails.name:match("^buildcraftbuilders:(.+)$") then
name = itemDetails.name:match("^buildcraftbuilders:(.+)$")
elseif itemDetails.name:match("^forge:(.+)$") then
name = itemDetails.name:match("^forge:(.+)$")
elseif itemDetails.name:match("^buildcraftenergy:(.+)$") then
name = itemDetails.name:match("^buildcraftenergy:(.+)$")
elseif itemDetails.name:match("^buildcraftfactory:(.+)$") then
name = itemDetails.name:match("^buildcraftfactory:(.+)$")
elseif itemDetails.name:match("^buildcraftsilicon:(.+)$") then
name = itemDetails.name:match("^buildcraftsilicon:(.+)$")
elseif itemDetails.name:match("^buildcrafttransport:(.+)$") then
name = itemDetails.name:match("^buildcrafttransport:(.+)$")
elseif itemDetails.name:match("^buildcraftcore:(.+)$") then
name = itemDetails.name:match("^buildcraftcore:(.+)$")
elseif itemDetails.name:match("^buildcraftlib:(.+)$") then
name = itemDetails.name:match("^buildcraftlib:(.+)$")
elseif itemDetails.name:match("^computercraft:(.+)$") then
name = itemDetails.name:match("^computercraft:(.+)$")
elseif itemDetails.name:match("^enderstorage:(.+)$") then
name = itemDetails.name:match("^enderstorage:(.+)$")
elseif itemDetails.name:match("^extracells:(.+)$") then
name = itemDetails.name:match("^extracells:(.+)$")
elseif itemDetails.name:match("^thermaldynamics:(.+)$") then
name = itemDetails.name:match("^thermaldynamics:(.+)$")
elseif itemDetails.name:match("^thermalexpansion:(.+)$") then
name = itemDetails.name:match("^thermalexpansion:(.+)$")
elseif itemDetails.name:match("^thermalfoundation:(.+)$") then
name = itemDetails.name:match("^thermalfoundation:(.+)$")
elseif itemDetails.name:match("^tconstruct:(.+)$") then
name = itemDetails.name:match("^tconstruct:(.+)$")
elseif itemDetails.name:match("^webdisplays:(.+)$") then
name = itemDetails.name:match("^webdisplays:(.+)$")
elseif itemDetails.name:match("^ironchest:(.+)$") then
name = itemDetails.name:match("^ironchest:(.+)$")
else
print("ERROR MOD NOT FOUND")
end
getBlock()
local elem = blockTypes[name]
--Gets fuel from fuel chest
right()
turtle.select(16)
turtle.suck(5)
turtle.select(15)
if elem then
--If the item does exist, the turtle goes to it's chest and places it in the chest
goTo(elem[1]-1, elem[2]-1, elem[3]-1)
turtle.select(15)
turtle.drop()
goHome()
right()
turtle.select(16)
turtle.drop()
turtle.select(15)
left()
else
--Creates information for new item--
addBlock()
blockAmount = blockAmount + 1
highestVal[3] = highestVal[3] + 1
if highestVal[3] > 5 then
highestVal[3] = 1
highestVal[2] = highestVal[2] + 1
end
if highestVal[2] > 4 then
highestVal[2] = 0
highestVal[1] = highestVal[1] + 2
end
blockTypes[blockAmount] = name
blockTypes[name] = {highestVal[1],highestVal[2],highestVal[3]}
local elem = blockTypes[name]
left()
turtle.select(15)
turtle.drop()
right()
turtle.select(16)
turtle.suck(2)
fuel()
turtle.drop()
goTo(1,-1,4)
--Crafts an Iron Chest for the New Item
for i = 1,3 do
turtle.select(i)
turtle.suck(1)
end
turtle.select(5)
turtle.suck(1)
turtle.select(7)
turtle.suck(1)
for i = 9,11 do
turtle.select(i)
turtle.suck(1)
end
turtle.select(6)
turtle.craft()
goTo(1,-1,3)
for i = 1,3 do
turtle.select(i)
turtle.suck(1)
end
turtle.select(5)
turtle.suck(1)
turtle.select(7)
turtle.suck(1)
for i = 9,11 do
turtle.select(i)
turtle.suck(1)
end
turtle.select(1)
turtle.craft()
goHome()
right()
turtle.select(16)
turtle.suck(5)
goTo(elem[1]-1, elem[2]-1, elem[3]-1)
turtle.select(1)
turtle.place()
goHome()
end
end
The file containing the coordinates for the items is called blockTable and consist of this:
--blockName = {xCoord,yCoord,zCoord};--
oak_stairs = {2.0,0.0,5.0};
iron_ingot = {2.0,0.0,4.0};
turtle = {2.0,0.0,5.0};
When I put a new item in, it registers the item, makes a chest, and puts it in. When I put the same item in, it goes straight to the chest without crafting a new one. However, when I reboot the turtle and put the same item in, it creates another new chest and tries to place it for the new item. I want it to be able to keep its information even after a reboot. I've been struggling with this program for a while now, any help will be appreciated. Thank you!

Answer 1

Reading / Writing the entire file every time you add a new block seems a bit messy, specially if you consider that you might restart the turtle in the process of writing the new file and end up with half your data being lost.
You do have a file system, so why not use that instead? Create a directory and write a new file for every block name, then save the coordinates in it. This also allows you to store more than one chest for each block-type, in case you get filthy rich happens sooner than you'd expect when using turtles to excavate huge chunks of the map.
I just realized that I didn't actually answer the question, so here goes that:
When you have a file file, you can easily read a single line with file.readLine(). This returns either the line it read as a string, or nil if you're at the end of a file. Assuming you just write three coordinates separated by spaces after the block name, you can then parse them into a table like this:
local file = fs.open('chests')
local chests = {}
while true do
local line = file.readLine()
if line then
local name, x, y, z = line:match("(%a+) ([%d.+-]+) ([%d.+-]+) ([%d.+-]+)")
chests[name] = {
tonumber(x),
tonumber(y),
tonumber(z)
}
else
break
end
end
Wrap this all up in a function for extra neatness.
Side note:
Computercraft is somewhat inconvenient for dealing with files. In regular Lua I would have done this:
local function map(f, elem, ...)
if elem then return f(elem), map(f, ...) end
end
local function readchests(file)
local res = {}
for line in io.open(file):lines() do
local name, x, y, z = line:match("(%a+)"..(" [%d.-+]+"):rep(3))
res[name]={map(tonumber, x, y, z)}
end
return res
end
If you want to keep the format of storing data as valid Lua code, you could read the entire file with file.readAll(), add "return {" at the start and "}" at the end and then just load and execute that string. In general I don't recommend that though. Id't be better if the entire file was just valid Lua code that you can read and run.

Answer 2

While it is not advisable to read the file every time you add to a new block as stated by DarkWiiPlayer.
To answer your question, you can read the table in and the execute the code from the string using loadstring.
To do this using the existing strings in the file you provided there is some extra work that is needed.
This extra work can be removed by adjusting your the string in the file.
blockTypes = {}
line = "oak_stairs = {2.0,0.0,5.0};"
table_name = line:match("[%a_]+%s")
do_line = assert(loadstring('local ' .. line .. ' return ' .. table_name))
table = do_line();
table.insert(blockTypes,table)
Here we get the name of the table being loaded using match.
Create a string for loadstring that builds and returns the table.
Execute the loaded string, and insert it to the blockTypes.
Alternatively you can adjust the file you are saving to that it acts as a module.
local blocktypes = {
oak_stairs = {2.0,0.0,5.0},
iron_ingot = {2.0,0.0,4.0},
turtle = {2.0,0.0,5.0},
}
return blockTypes
Then you would this to load the data:
blockTypes = require("blockTable")