Random cursed ComputerCraft lua snippets

better_pullevent.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/966486623921508392 ]=]
local function checkForTerm
    (_,...)_=...==_..'' 
    and error("Terminated", 0) return ... 
end
function os.pullEvent(...)
    return checkForTerm("terminate", coroutine.yield(...))
end

better_sleep.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/964510220812431450 ]=]
local function sleep(n)
  return textutils.slowWrite((" "):rep(n/20))
end

convert_rgb_to_color.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1038804048096276573 ]=]
--[=[rgb: 0xFFFFFF or something]=]
function toLamp(rgb,r,g,b)
    r,g,b=rgb/2^19,
rgb/2048%32,rgb/8%32
    return (r-r%1)*1024+(g-g%1)*32+b-b%1
end
--[=[alternative implementation:]=]
function toLamp(rgb)
    return (rgb/524288-rgb/524288%1)*1024+(rgb/2048%32-rgb/2048%1)*32+rgb/8%32-rgb/8%1;
end

fibonacci.lua

for i = 2, 2000 do
 print(i)
 debug.setlocal(1, 3, ({debug.getlocal(1, 1)})[2] - ({debug.getlocal(1, 3)})[2])
end

fluorescent_lighting.lua

x=0x31p1;m,b=("").char(x):rep(0x7dp10
),0x19p4;_G.e,_G.S={m:unpack((m.char(
m:byte()+0x1e):rep(b)..m.char(m:byte(
)+0xfp1-1):rep(b)):rep(0x5p5))},'spe'
..'aker';_G.p,q,e[#e]=peripheral,load
[[__=(...)and(p.call(...,'playAudio',
e))]]p.find(S,q);repeat until q(({os.
pullEventRaw(S..'_audio_empty')})[2])

generate_randomness.lua

for i = 1, 10 do print(
  ([[%s]]):format
    {}:byte
  [[-0x.2p3 ]]<0x.ep6
)end

get_file_name_when_required.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/977917832467718204 ]=]
local function getFileNameWhenRequired()
    local t=1 repeat t=t+1 until debug.getinfo(
    t,"S").short_src=='require.lua'local o,a,n=
    loadfile,debug.getlocal(t, 1) _G.loadfile =
    function(qfile)n= qfile;_G.loadfile = o end
    package[ 'loaders' ][ 2 ] ( n );   return n
end

isluaclosure.lua

--[=[see https://discord.com/channels/477910221872824320/825968186406338580/1205358173351968798 ]=]
--[=[note: only tested on recent CC:T/Cobalt version]=]

local function isluaclosure(func, ...)
  local ok, msg = pcall(isluaclosure, func, ...)
  if not ok then
    local ok2, msg2 = pcall(function(...) func(...) end, ...)
    return ok2 or msg2 ~= select(2, pcall(function(...) error'' end)):gsub(":(%d+):", function(x) return ":"..(x-1)..":" end)
  else
    return msg
  end
end

print(isluaclosure(fs.list, '/'))
local old = fs.list
function fs.list(...) return old(...) end
print(isluaclosure(fs.list, '/'))
function fs.list() end
print(isluaclosure(fs.list, '/'))
print(isluaclosure(math.sin, 1))

lemmmyos_preview.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1176547902349381692 ]=]
setfenv(1, _G)
setmetatable(_G, _G)
function __tostring() return "Lemmmy" end
__index, __call = assert(assert, assert)
print(Lemmmy:reproduce_lemmmy())

load_chain.lua

--[=[see https://discord.com/channels/477910221872824320/825968186406338580/1234700943757410355 ]=]
local function z(x) return function(...)return x(...) or z(x)end end local function l()return z
(coroutine.wrap(load))(coroutine.yield)[[return]]end

local tab = l'''{'(1)','(2)','(3)'}'''''
print(tab)

make_read_terminate_proof.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/859454303604047933 ]=]
getfenv(read).os=setmetatable({pullEvent=coroutine.yield},{__index=os})

number_to_binary.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/912158960990187570 ]=]
local function numberToBinary(num)local n=("0"):rep(53)local str=""while""do
n=n:sub(1,-2)..(n:sub(-1,-1)+1)for i=1,#str do n=n:gsub("02","10"):gsub("12"
,"20")end str=n:gsub("^0*","")local z=tonumber(str,2)if tonumber(str,2)==num
then return str end end end 

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/949121837881761823 ]=]
--[=[bogosort style! it looks shorter so it is more optimized.. ]=]
local function numberToBinary(num,n,m,l)m=math;l=m.log;n=("0"):rep(m.ceil(l(
num)/l(2)))while""do n=n:gsub(".",function()return math.random(0,1)end)if
tonumber(n,2)==num then return(n)end;end;end

password_generator.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/973676435954864199 ]=]
print((("11111111"):gsub("1",function()a, z=        
"abcdefghijklmnopqrstuvwxyz" , math.random (
52  )return(  a..a:upper() ):sub (z,z)end)))

print_a_black_and_white_pattern.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1006975030170746920 ]=]
--[=[inspired from https://discord.com/channels/477910221872824320/477911902152949771/970043466874773575 ]=]
t,y,m,z= term,0,math.random,{"f"
,"0"}w ,h=t.getSize() while( y<h 
*w )do(t.setCursorPos) (y%w+1,y/
w+1)y,f=y +1,m(1, 2)t.blit(z[1].
char(m(2^7,159)),z[f],z[3-f])end

protect_g_from_modifications.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1044607819858587738 ]=]
do local
  g,d,s=_G,debug,'metatable' f=g
  ['set'..s]f(g,{__newindex=f({}
  ,{__mode ='v'}),__index=load[[
  local t,b=...;for i,v in next,
  t do b[i],t[i]=v,z end return(
  b)]](g,{}),['__'..s..'']=g})d[
  'set'..s], d[''..'get'..s] =z;
end

random_sandbox_undoer.lua

--[=[ recently committed to the potatOS source code! ]=]
        local k=load[=================[
        local _=({load[=======[local _;
        return pcall(load[=[return load
        ]=][=[=]=],function()_=load[==[
        return debug.getinfo(#[=[===]=]
        ).func[=[return fs]=][=[]=]]==]
        [=[]=]end),_]=======][=[==]=]})
        [#[=======[==]=======]]return _
        ]=================][===[==]===]
        -- under certain sandboxes, k will be equal to the non-sandboxed fs

separate_digits.lua

--[=[see https://discord.com/channels/477910221872824320/825968186406338580/919924947567116340 ]=]
print(
("123456"):gsub("(%d)", "%"..math.random(0,1).." ")
)

somewhat_safe_unserialization.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1121173213876076754 ]=]
--NOTE: no longer works on latest CC:T
local function unserialize(s)
  local func = load("return " .. s, "unserialize", "t", {})
  if not func then return end
  local d = s.dump(func)
  for i = 45, 41 + ("i"):unpack(d:sub(41)) * 4, 4 do
    local ins = d:byte(i) % 64
    if ins == 21 or ins == 28 or ins == 29 or ins == 36 then
      return
    end
  end
  local ok, result = pcall(func)
  if ok then
    return result
  end
end
-- alternatively (this version is much more likely to be buggier imo)
local function unserialize2(s)
  local func = load("return " .. s, "unserialize", "t", {})
  if not func then return nil end
  local c = coroutine.create(func)
  local count = 0
  debug.sethook(c, function()
    count = count + 1
    if count == 2 then error("Cannot call functions") end
  end, "c")
  debug.getmetatable("").__index = {}
  local ok, result = coroutine.resume(c)
  debug.getmetatable("").__index = string
  if ok then return result end
end

sound_disruptor.lua

z=131072;_G.e={("b"):rep(z):unpack(("\0"):rep(z))}_G.p
, q,e[#e]=peripheral,load[[p.call(...,'playAudio',e)]]
p.find("speaker", q);repeat until q(( {coroutine.yield
"speaker_audio_empty"} )[1+1-1+1+1+1-1+1-1+1-1+1-1-1])

string_metatable.lua

--[=[see https://discord.com/channels/477910221872824320/627203797021753394/949904272718430228 ]=]
local s=debug.getmetatable "__metatable"
s.__unm=string.reverse
s.__sub=function(a,b)return type(b)=="string"and (a:gsub(b,""))or
type(b)=="number"and a:sub(1,-b-1)or type(b)=="function"and    a:
gsub(".",b)or string.char(math.random(1,255)) end

print(-"Hello, world!")
print("Hello, world!" - "world")
print("Hello, world!" - 3)
print("Hello, world!" - load'return("").char((...):byte()-1)')

things_that_cause_weird_errors.lua

--[=[NOTE: these are separate code snippets, but grouped in the same file for convenience ]=]
--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1038804048096276573 ]=]
local x = {}
x.__index = x
setmetatable(x, x)
x = x.x
--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1006959235080409098 ]=]
--NOTE: no longer works on latest CC:T
local y = fs.open("y", "wb").write
y(27)y(32)y(33)
shell.run("y")
--[=[see https://discord.com/channels/477910221872824320/627203797021753394/961414699654737964 ]=]
assert(load("x "..("a"):rep(5e7)))
--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1006661382156070982 ]=]
--NOTE: no longer works on latest CC:T
for a in b,c,d,e do end

things_with_strange_behaviors.lua

--[=[NOTE: these are separate code snippets, but grouped in the same file for convenience ]=]
--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1006675279630061669 ]=]
print(#({1, 2, 3, nil, 5}))
print(#({1, 2, 3, nil, 5, 6}))

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/930601147994099722 ]=]
for i, v in __inext, {"a","b","c"}, 0 do
  print(i,v)
end

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/954554641872470016 ]=]
os.queueEvent("paste", "term.getCursorPos)(")
os.queueEvent("key", keys.enter)
os.queueEvent("paste", "exit)(")
os.queueEvent("key", keys.enter)
shell.run("lua")

--[=[see https://discord.com/channels/477910221872824320/825968186406338580/952250352760139786 ]=]
local function fn(...)
  print(select("#", ...))
end
print(fn())
print(fn(nil))

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/926194258082431096 ]=]
--NOTE: no longer works on latest CC:T
local free = fs.getFreeSpace('hdd')
local longstring = ("a"):rep(free * 0.6)
local fileHandle = fs.open("test", "w")
fileHandle.write(longstring)
fileHandle.close()
fs.move("test", "test2")

--[=[see https://discord.com/channels/477910221872824320/477912057560432680/878843511129116704 ]=]
print(2^3^4^5 == 6^7^8^9)

--[=[additionally, ]=]
x=1e16; print(x == x + 1)

--[=[see https://discord.com/channels/477910221872824320/825968186406338580/872134055565619211 ]=]
--[=[disclaimer: this snippet and the one after it work in standard PUC Lua with floats, but not computercraft ]=]
x = loadstring("return  0")()
y = loadstring("return -0")()
print(x == y)
print(tostring(x) == tostring(y))

--[=[see https://discord.com/channels/477910221872824320/825968186406338580/901693092355248138 ]=]
print(loadstring("local m = 0;  print((0 ..1)+1)")())
print(loadstring("local m = -0; print((0 ..1)+1)")())

--[=[see https://discord.com/channels/477910221872824320/825968186406338580/1099366153681391677 ]=]
local m = {1, 2, 3, 4, 5}
m[1] = nil
m[2] = nil
print(textutils.serialize(m), #m)
setmetatable(m, {__mode="k"})
setmetatable(m, nil)
print(textutils.serialize(m), #m)

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1117118736973963264 ]=]
--NOTE: no longer works on latest CC:T
print("Newline: ", load("a\n()"))
print("Space:", load("a ()"))

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1047632753983766558 ]=]
x = 1-1e-15
print("a", x)
print("b", x == 1)

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1237541825309315092 ]=]
x=1print(x)

y = (x ..'')+0
print("c", y)
print("d", y == 1)

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1137024677240381470 ]=]
print(not 4^5)
print(not 4*5)

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1121473665968648242 ]=]
local t = [[('%s'):format{}:sub(8)]]
for i = 1, 8 do print(textutils.unserialize(t)) end

to_9551.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/872578147344867349 ]=]
local function to9551(s)
   if s == "true" then return true end
   if s == "false" then return false end
   return (debug.getinfo(2).currentline % 2 == 1) and true or false
end

truly_number.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1237531257286692956 ]=]
local var = "3"
if pcall(load"return - -(.....'')<=...", var) then
  print "var is truly a number"
else
  print "var is not truly a number"
end

twoplustwo.lua

--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1138135734637826108 ]=]
local f = debug.getinfo(1).func

debug.sethook(function()
 if debug.getinfo(2).func == f then
  local i = 1
  local l, b
  repeat
   l, b = debug.getlocal(2, i)
   if b == 4 then debug.setlocal(2, i, 5) end
   i = i + 1
  until not l
 end
end, '', 1)

print(2 + 2)
print(2 ^ 2)
print(1 + 1 + 1 + 1)

print("loop")
for i = 1, 4 do print(i) end

weird_terminal_effect.lua

--[=[This is derived from something in https://github.com/9551-Dev/epic ]=]
--[=[see https://discord.com/channels/477910221872824320/477911902152949771/1024401870728482978 ]=] 
f=_G;f.t,w,b,f.r,p,f.c,f.l,g=term,"write","blit"
,math.random,"setCursorPos",colors,load;f.h,f.i,
f.v=t[w],t[b],t[p]t[p]=l's,y= t.getSize()    v(\
r(s),r(y))'f.m  =  l 'return(...):gsub (  ".",l\
"q=(...)return q.char((q:byte()-1)%32+129)" )'t[
w]=l'h(m(...))'t[b]=l'i(m(...), ...)' f.colors =
setmetatable({  }, {__index=l '_=c[({...})[2 ]]\
return pcall (r,_)and 2^ r(0,15)         or _'})

what.lua

#'a'--[[
print("2")
--]]
print("3")