I don't have a lot of coding experience, did some C a few years ago, so that helps, but Lua handles things a bit differently, so I can't keep track.
I sometimes (not always) get this error when a friend or guildy logs into the game:
Date: 2013-06-14 16:57:57
ID: -1
Error occured in: Global
Count: 4
Message: ..\AddOns\Tukui\scripts\chat.lua line 335:
attempt to concatenate upvalue 'classColor' (a nil value)
Debug:
[C]: ?
Tukui\scripts\chat.lua:335: AddMessage()
..\FrameXML\ChatFrame.lua:2755: ChatFrame_MessageEventHandler()
..\FrameXML\ChatFrame.lua:2491: ChatFrame_OnEvent()
...s\WIM\Libs\LibChatHandler-1.0\LibChatHandler-1.0.lua:281:
...s\WIM\Libs\LibChatHandler-1.0\LibChatHandler-1.0.lua:252
...s\WIM\Libs\LibChatHandler-1.0\LibChatHandler-1.0.lua:308:
...s\WIM\Libs\LibChatHandler-1.0\LibChatHandler-1.0.lua:296
I have to do a reload of the ui after this happens to be able to see chat text again for that person.
Line 335 in that .lua file is this:
text = replace(text, "^|Hplayer:(.+)|h%[(.+)%]|h", "|Hplayer:%1|h|cff"..classColor.."%2|r|h")
Now I've learned that the .. indicates the concatenate function, but that isn't really helping me.
I don't know if this is enough information, but if you need it I can post the whole local function or whatever else is required.
If it makes any difference, I'm running the 3.3.5a WoW client.
You are probably using a global that gets defined from some other addon in a now deterministic way
While the (classColor or "") will get you rid of the error, you should try and find why that variable (classColor) is sometimes defined and sometimes not. Maybe it happens only for certain classes?
A simple hack would be to just replace
..classColor..
with
..(classColor or "")..
where it will select a blank string when classColor has no value assigned to it.
Related
I am learning how work with files in Lua, and I came across a problem.
I know that:
io.output() allows me to specify the file that I will write output to.
The io.write() function simply gets a number of string arguments and writes them to the current output file.
io.close() then closes the file I am reading or writing on.
I first set io.output() to "myNewFile.txt" then I did io.write("Hello World!").
io.output("myNewFile.txt")
io.write("Hello World!")
This part worked well and myNewFile.txt got Hello World written to it.
Then I wrote io.close() to close the myNewFile.txt.
After that, I wrote io.write("Hello World!"), but I got an error:
C:\\Program Files\\lua\\lua54.exe: ...OneDrive\\Documents\\learning lua\\steve's teacher\\main.lua:9: default output file is closed stack traceback: \[C\]: in function 'io.write' ...OneDrive\\Documents\\learning lua\\steve's teacher\\main.lua:9: in main chunk \[C\]: in ?
I wanted io.write("Hello World!") to write Hello World in the terminal. I know can use print() but print() function adds extra characters like \n and things like that.
So my question is, how do I write Hello World in the terminal using io.write("Hello World!") in this situation?
I tried to search this error up on Google, but there weren't any results. I also tried joining many Discord servers, but I didn't get a proper response. I am a new developer to Lua so this all is really confusing to me.
After io.close() do a io.output(io.stdout) to set it back.
The clean way
local oldout = io.output() -- without argument returns actual output
io.output("file") -- set to a filename
-- do file operations here
-- use io.flush() where it is necessary
io.close() -- close file also do a flush()
io.output(oldout) -- set back to oldout ( normally io.stdout )
-- changing io.output() back should also close() and flush() the "file"
-- But better doublecheck this when using userdata without experience
I'm attempting to constantly read and parse a log file (Minecraft log file) by using io.popen in tandem with Ubuntu's tail command so that I can send some messages upon certain events.
Now, I have mostly everything working here, except one small issue. After a while of reading, the entire program just freezes.
Here is the relevant code:
-- Open the tail command, return a file handle for it.
local pop = io.popen(config.listen_command)
-- Simply read a single line, I've pulled this into its own
-- function so that if this ever needs changing I can do so
-- easily.
local function get_line()
logger:log(4, "READ LINE")
return pop:read("*l")
end
-- For each line in the log file, check if it matches any
-- of a list of patterns, return the matches and the
-- pattern information if so.
local function match_line()
local line = get_line()
logger:log(4, "Line: %s", line)
-- This all works, and I've tested that it's not freezing
-- here. I've just included it for completion of the call
-- -stack.
for event_type, data in pairs(config.message_patterns) do
for event_name, pattern in pairs(data) do
local matches = {line:match(pattern)}
if matches[1] then
return event_type, event_name, matches
end
end
end
end
-- The main loop, simply read a line and send a message
-- if there was a match.
logger:log(4, "Main loop begin.")
while true do
local event_type, event_name, matches = match_line()
-- ...
-- The rest of the code here is not relevant.
config.listen_command = "tail -F --lines=1 latest.log"
The issue is in the get_line function. After a while of reading the log file, it completely freezes on the pop:read("*l"). It prints the READ LINE message, but never prints the Line: <whatever data here> line.
This is a really strange issue that I've been getting really confused about. I've tried swapping to different distributions of Lua (Luvit, LuaJIT, Lua) and a very large amount of debugging, changing small things, rerunning, ... But I cannot think of anything that'd be causing this.
Perhaps there's something small I've missed.
So my question here is this: Why is pop:read("*l") freezing, even though more data is being outputted to the logfile? Is there a way to fix this? Perhaps to detect if the next read will freeze indefinitely, so I can try closing the popen'ed file and re-open it (or to preferably stop it happening altogether?)
I'm following your roguelike tutorial and have encountered a problem I do not know how to solve. This is my first-time coding with Lua
If r.nospawn then return 0
--Attempt to index local "R" (a nil value)
I asked the PICO-8 discord server, they tried to help me, but I still don't fully understand, and I did not want to pester them further with the issue. The name of my file on PICO-8 is called Rogue - if that has anything to do with the issue.
Here's a picture of the error, the discord comment I received, and a link to the full list of code on GitHub.
Error in PICO-8
Discord Comment
Github Code
I think you are missing a simple failure case. i.e. what happens when all the entries in rpot have been removed. Then local r=getrnd(rpot) should return null. That might be an error in it's own right i.e. there should always be something to allocate from there.
However getrnd will fail.
function getrnd(arr)
return arr[1+flr(rnd(#arr))]
end
In the case when arr is empty you will try and return element 1, which will be out of bounds. I don't know lua but it might return null for you which leads to the next problem. But that has a simple fix:
repeat
local r=getrnd(rpot)
if r
placed+=infestroom(r)
del(rpot,r)
end
until #rpot==0 or placed>maxmons[floor]
This is my first time using Lua, and with following a tutorial, Im making a chat program, allowing two players to send and receive messages to each other. The receiving is called chatreceive.lua. The script is:
rednet.open("right")
sender, message = rednet.receive()
print("computer " .. sender .. " has sent :")
print(message)
I keep getting an error saying
chatreceive.lua:3: attempt to concatenate global 'sender' (a nil value)
Any solutions? Ive been trying for a while now
That means that the variable 'sender' was nil. This probably means that there was some sort of error with rednet. You should add a lot of checks to make sure your programs don't fail in critical situations:
if sender==nil then
print("SENDER IS NIL!!!")
end
Also, what version of CC are you using? You shoud be more specific, to get better answers...
I am trying to make a simple UI using qtlua, in which I want to capture the slider value everytime it changes. I tried to connect to the valueChanged() signal, but qlua gives me the following error:
cannot find source signal valueChanged()
The code snippet looks like this:
slide = (widget.sliderLight)
print(slide)
qt.connect(slide, 'valueChanged()',
function()
print('Value: ', slide.value)
end)
So just a test to print everytime the value changes. But I cannot get it working. The documentation for the qtlua doesn't have a class for qslider, so that's a dead end for me. And I couldn't find any examples for using qtlua with a slider that is connected to the valueChanged() signal. The only example I found was with the test.lua in the qtuiloader example, but that uses a timer, which I assume is pooled at regular interval. My aim is to hook this up to an image processing system, so it would be useful if I could tie it to when the value changes, rather than patch in with a timer and a check system. I am pretty new to qt, so must be missing something. Any and all help would be really appreciated!
Oh and I made sure I have tracking checkbox checked in the qtdesigner, to ensure that the signal is emitted.
Okay, so I dug around a little more in the documentation of QT for the valueChanged() slot. Turns out, the function signature has an int argument in it, so the Lua connect code was looking for a function signature without any arguments. Modifying the above code to the following works as expected:
slide = (widget.sliderLight)
print(slide)
qt.connect(slide, 'valueChanged(int)',
function(w)
print('Value: ', w)
end)
Declaring a function with the same signature also passes in the required value, which saves me an explicit value query.
Hopefully, this will be useful for someone someday.