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News and discussion for the Lua programming language. Subreddit: https://www.reddit.com/r/lua Powered by : @r_channels & @reddit2telegram
A way to make cross-platform (Windows, Mac, Linux at least), GUI-based apps that support an acrylic-like background in Lua?
Hey Lua users, i was wondering if you knew a way to make a GUI-based application that would work on Windows, Mac and Linux and who would support acrylic / gaussian-blur Windows backgrounds in Lua.
(similarly to how Glasstron works for Electron apps)
https://redd.it/ljwjs3
@r_lua
Question on Tables
I've got a question on tables. I'm new to lua. I started picking it up a few weeks ago to script a Digital Loggers LPC9 Web Power Switch Pro. Mostly going OK with the usual learning curve. But one thing has me stumped.
In the firmware of the LPC9 is a built-in function wait_until(). It takes a table input, waits until the system clock matches one of the table entries, then returns a value corresponding to which entry is matched.
When I make the call like this:
local event = wait_until ({hour = 11, min = 0}, {hour = 13, min = 0}, {hour = 15, min = 0},
{hour = 17, min = 0}, {hour = 19, min = 0}, {hour = 21, min = 0} )
everything works as expected. Every day on the odd hours between 11a and 9p I get an event trigger. My problem is I'm writing the script for someone else and rather than have them dig in the code to configure the event timer, I thought I'd set up an easily accessible global they can use. I've been testing with a second local variable and I've tried:
local Temp = {hour = 11, min = 0}, {hour = 13, min = 0}, {hour = 15, min = 0},
{hour = 17, min = 0}, {hour = 19, min = 0}, {hour = 21, min = 0}
local event = wait_until (Temp)
but the trigger never fires. Same with:
local Temp = { {hour = 11, min = 0}, {hour = 13, min = 0}, {hour = 15, min = 0},
{hour = 17, min = 0}, {hour = 19, min = 0}, {hour = 21, min = 0} }
local event = wait_until (Temp)
I've tried a couple other things too, but they all fail to fire the event.
What am I doing wrong? Can someone provide a solution?
Thanks ....
\- Joe
https://redd.it/lj6vpe
@r_lua
Interesting little Medium article on Lite, the new editor written in Lua
https://medium.com/swlh/i-switched-to-lite-after-using-vscode-for-3-years-16f2fffa6143
https://redd.it/li7a26
@r_lua
Logitech lua reliable Sleep function
Hi!
​
I am kind of new to lua scripting, so please forgive me if I say something wrong.
I am writing a lua script for my logitech mouse. The logitech lua api has this documentation.
My script moves the mouse every x milliseconds to draw a pattern. My problem is that the Sleep(x) function of thislua api is very inaccurate. I have read that it takes time (couple milliseconds) for it to get a thread, so that time adds to the execution time for the code itself. However it makes it useless for measuring milliseconds.
Do you know a workaround? Is there a more capable way for measuring milliseconds than the Sleep(x) function?
Also I wanted to note that in windows 10 version 1909 and bellow, it was much-much more accurate. They have messed something with it so it is inaccurate since windows 10 version 2004 (aruound august, last year). So I would need to find a workaround for this.
​
Here is a snippet from my code:PressMouseButton(1)--1MoveMouseRelative(-26, 36)Sleep(127)--2MoveMouseRelative(2, 36)Sleep(127)--3MoveMouseRelative(-36, 32)Sleep(127)--4MoveMouseRelative(-33, 30)Sleep(127)--5MoveMouseRelative(-11, 38)Sleep(127)ReleaseMouseButton(1)
This does not function on its own, but you can see here how I want to use the function.
​
Thank you for your help!
https://redd.it/lhjtww
@r_lua
Does anybody know any good tutorials for Lua?
So, recently came across Lua, and I am starting to like its syyntax and perfomance. Does anybody know any nice resources for learning the language, please don't recommend Programming in Lua, its much too complicated for me.
https://redd.it/lgo00y
@r_lua
I have a question about metatables
1. The parameters of for example, the metamethod add is (table, value), so why can you set it equal to a function and have the parameters changed to add(table, table)
ex: add = function(tb1, tb2)
return { value = tb1.value + tb2.value }
https://redd.it/lgaiia
@r_lua
How do i use add in metatables?
Module
local meta = {}
function meta.new(x)
local self = setmetatable({},{index,meta})
self.x = x
return self
end
return meta
Main
local m = require("metatest")
local a = m.new(25)
local b = m.new(7)
local c = a+b
print(c.x)
I want to be able to add a and b together with the + operator. How would i do that?
https://redd.it/lfm4mb
@r_lua
Is there a better way to do this?
If you need to check let's say 30 cases with a variable and instead of using:
if-elseif-elseif-elseif
Would there be a better way to do this?
https://redd.it/ld8khv
@r_lua
Testing for nil in multidimensional tables where table dimensionality can vary?
Hi,
Lately I am having to write a ton of conditional statements to check for existence of nils.
For instance, I have tables, whose dimensions can vary. Some table might have an entry
te = table1"key1""key2"
I can't do tests like
if table1"key1""key2"==nil
because table["key1"\] has to exist first, if I understand lua correctly.
So lately, my code is becoming a mess, because depending on the dimensionality of a table, I have these nested conditional checks like
if table"key1"~= nil then
if table"key1""key2"~= nil then
... and so on ...
Being new to lua, maybe I am just missing some obvious point and I am making things way more complicated than needed?
​
thanks!
https://redd.it/ld2id2
@r_lua
How can I test if every value in a table is true?
How can i test if every element in a table is true? And if everything is true do something.. but if one thing is false, then do not do something?
https://redd.it/lccolr
@r_lua
A pattern to find integers in strings like 'xx 11 22 03 34a' but exclude 34a
Hi,
In the example string, s = 'xx 11 22 3 34a'
I am trying to loop through the string using string.find(s,p,i), so I can return integers
11, 22, 3
34a wouldn't count as a match, since I want only numbers that either are surrounded by space, or followed by nothing. I almost have things working withb,e,num = s:find("%s(%d*)%s?", start)
where in the loop I am setting start to e for the next iteration.
But I can't figure out a pattern that will work that will prevent that 34a from being counted. I tried variations with %A at the end, but nothing seems to be working.
Also it needs to work in cases like
s = 'xx 11 22 3 34 yy'
Where in this case 34 is matched. That is, there is nothing special about the position of the last possible match. It can be a number at the string termination, etc, etc.
Ideas?
https://redd.it/lbt2ta
@r_lua
Understanding what foo'bar' means and does
Hi, I need help understanding code similar to foo['bar'\]() means. In a distro, I found this line of code:
file 1
other stuff
gStateMachine = StateMachine {
'start' = function() return StartState() end,
'play' = function() return PlayState() end
}
another file
-- other stuff
function StateMachine:change(stateName, enterParams)
assert(self.statesstateName) -- state must exist!
self.current:exit()
self.current = self.statesstateName -- what does this mean?
self.current:enter(enterParams)
end
What does
self.current = self.statesstateName
do?
https://redd.it/lbjupu
@r_lua
Luaver - simple Lua version management
https://github.com/guidanoli/luaver
https://redd.it/l9eshm
@r_lua
Need help understanding recursion and the Eight Queen Problem (PiL 4th edition)
I'm having some trouble solving Exercise 2.1 in PiL, which asks to modify the 8 queen problem so that it stops printing after the first solution. The way I solved it feels more like a hack. Here's my code, which merely moves the first call to printsolution() to the end of the function and replaces the call to addqueen() with a return statement instead.
I know that there's no way to "break" out of a recursive function and that you pretty much have to wait until control is returned to the top level function that started the recursive chain. But without moving the printsolution call, I'm at a complete loss as to how to do this.
N = 8
-- board size
-- check whether position (n,c) is free from attacks
function isplaceok (a, n, c)
for i = 1, n - 1 do
-- for each queen already placed
if (ai == c) or
-- same column?
(ai - i == c - n) or
-- same diagonal?
(ai + i == c + n) then
-- same diagonal?
return false
-- place can be attacked
end
end
return true
-- no attacks; place is OK
end
-- print a board
function printsolution (a)
for i = 1, N do
-- for each row
for j = 1, N do
-- and for each column
-- write "X" or "-" plus a space
io.write(ai == j and "X" or "-", " ")
end
io.write("\n")
end
io.write("\n")
end
-- add to board 'a' all queens from 'n' to 'N'
function addqueen (a, n)
if n > N then
-- all queens have been placed?
--printsolution(a)
else -- try to place n-th queen
for c = 1, N do
if isplaceok(a, n, c) then
an = c
-- place n-th queen at column 'c'
return addqueen(a, n + 1)
end
end
end
printsolution(a)
end
-- run the program
addqueen({}, 1)
https://redd.it/l8te1a
@r_lua
Does Lua not allow top level expressions?
Not so much a question, rather I would like to expand my understanding of the Lua syntax. It seems that Lua, unlike JS/Python/Ruby, does not allow expressions unless they are enclosed in a statement. Is this correct?
This works:
print(2 + 2)
-- => 4
2 + 2
-- stdin:1: unexpected symbol near '2'
Moonfltk help needed on Sparky.
Hello Stefano, I've posted another question in the issues on your github page. Cheers, Jon.C.
https://github.com/stetre/moonfltk/issues/24
https://redd.it/ljcw25
@r_lua
Lua Quick Guide
I use neovim, which uses Lua as one of its scripting languages. I've been meaning to learn Lua for a while but haven't found the time. I know there are lots of guides online. I usually find them either too long (too much time spent on the basics), too short (syntax just gets thrown at you without much explanation), or too disorganized (no specific order to progress through the language). I decided to put together my own guide while learning the language that is neither too long nor too short and in which there's an order to the natural flow of the content. You can find it here. I believe if you're new to Lua and are already familiar with programming concepts, you will really find this guide useful as I spend very little time discussing the obvious things and expound a bit on the things that are unique to Lua.
As a disclaimer, I've only been using Lua for 3 days. So, I might not have captured all the important facets of the language.
https://redd.it/lizpf6
@r_lua
luaJIT graphics api for use with Luvit?
Are there any good luaJIT graphics apis that are compatible with luvit? i haven't found any because with i search "luvit graphics" on google i get a bunch or graphic design stuff.
https://redd.it/lhl49u
@r_lua
Class Browser for Lua
Is there a class browser for Lua that works with it's metatables that anybody knows of?
Is there a known possible VSCode extension or alternative editor?
https://redd.it/lhc3ie
@r_lua
Is the math.random biased for more even values?
I was just messing around and wanted to find a random seed that would give really high numbers. I did a for loop to find the sum of the first 100 random digits of the first 1,000,000 seeds. I know the expected sum should be 50, and I got a max of 63.413 with the seed 622611. This seemed low so I did the sign test and it said I should expect results like this around 1/4000 trials if it was truly random. I looked up source code and it seems to be shifting some numbers around with pointers, but is this known to be biased towards a more even random result?
https://redd.it/lgk45t
@r_lua
Video with a code review of a code base in Lua (Recording Videos in REAPER (Through OBS))
https://youtu.be/dxfM4ftB1hM
https://redd.it/lg0dj0
@r_lua
I need a step-by-step guide on how to use the official lua executor.
I already have the script and i downloaded the .zip of the executor from github, what do i do now?
https://redd.it/lf53pa
@r_lua
Passing in self in an object to index self without actually declaring self?
I'm confused about how this code works. the onCollide takes in a function as an argument, and the function takes in obj. When I hover over the obj it says that obj is of type table, but in the rest of the code there is no declaration of obj as a table. And since you can index obj.hit and change it's value, does it mean it's refering to itself?
How does lua know what obj is without me actually declaring it
I'm confused about this.
​
-- other stuff
table.insert(objects,
-- jump block
GameObject {
texture = 'jump-blocks',
x = (x - 1) TILE_SIZE,
y = (blockHeight - 1) TILESIZE,
width = 16,
height = 16,
-- make it a random variant
frame = math.random(#JUMPBLOCKS),
collidable = true,
hit = false,
solid = true,
-- understand more in depth tomorrow
-- collision function takes itself
onCollide = function(obj)
-- spawn a gem if we haven't already hit the block
if not obj.hit then
-- chance to spawn gem, not guaranteed
if math.random(5) == 1 then
-- maintain reference so we can set it to nil
local gem = GameObject {
texture = 'gems',
x = (x - 1) TILE_SIZE,
y = (blockHeight - 1) TILESIZE - 4,
width = 16,
height = 16,
frame = math.random(#GEMS),
collidable = true,
consumable = true,
solid = false,
-- gem has its own function to add to the player's score
onConsume = function(player, object)
gSounds['pickup']:play()
player.score = player.score + 100
end
}
-- make the gem move up from the block and play a sound
Timer.tween(0.1, {
[gem] = {y = (blockHeight - 2) * TILESIZE}
})
gSounds'powerup-reveal':play()
table.insert(objects, gem)
end
obj.hit = true
end
gSounds'empty-block':play()
end
}
)
end
https://redd.it/ld353w
@r_lua
Rock Paper Scissors Help
I am new to lua and wanted to practice by constructing a rock paper scissors game. Though I am running inot a problem when I run my code saying "lua: [string "<eval>"\]:9: attempt to perform arithmetic on a string value
stack traceback:
[string "<eval>"\]:9: in main chunk"
Here is my code:
print("Hello Welcome to Rock Paper Scissors. Choose 1")
local input = io.read("*l")
local choices = {"rock", "paper", "scissors"}
local computerchoice = choices[math.random(3)\]
if input==computerchoice then
print("The computer chose" + computerchoice + " . Its a tie")
elseif input=="rock" and computerchoice=="scissors" or input=="paper" and computerchoice=="rock" or input=="scissors" and computerchoice=="paper" then
print("The computer chose " + computerchoice +". You won!")
else
print("The computer chose "+ computerchoice +". You Lost :(")
end
https://redd.it/lczgjv
@r_lua
TED: a Text EDitor for CLI made in lua
Exactly what the title says
Made in 1.5 days in a phone
No external libraries or frameworks
One small file
Funny name (kind of)
Runs in Luajit(5.1) but should work on newer versions
Infinite argument support
Meant for quick and easy automation
Read and write to files
GitHub repo
https://redd.it/lc80vf
@r_lua
Lua and sorting... numeric keys, numeric values
Hi, say you have a table of integers.t={2,4,6,1}
These integers index into another table to retrieve some number valuesomenum=othertable[2]
Now for each index in t, I know its associated number and end up with this table, for instancenums={[2]=num1, [4]=num2, [6]=num3, [1]=num4}
num1, num2, etc can be the same.
I need to sort by ascending order based on these num1, num2, etc, so that in the end I have the indices in t ordered based on num1, num2, etc.
So if I have tn={[2]=12, [4]=4, [6]=3, [1]=6} I need to end up withnums = [6]: 3[4]: 4[1]: 6[2]: 12
Make sense? Or better yet just end up with {6,4,1,2}. Been messing with table.sort, which is not producing what I need.
For instance, here is what I have:
nums={}
for ti in ipairs(t) donums[ti] = othertable[ti][2]
end
table.sort(nums, function(a,b) return a < b end)
This returns a table with its values sorted, but the indices are in consecutive order, not telling me the correct order of of the keys.
Can't figure out what I am doing wrong...
https://redd.it/lbluo1
@r_lua
[OC] A video about a cool project using the Minecraft mod ComputerCraft to make self replicating probes
https://youtu.be/xvjcM1Hpr6o
https://redd.it/lb78i8
@r_lua
Destroy() Function on Gui does not work, Please help
so Ive been making some dialogue and when you click the option sure I wanted a Gui to destroy Here is the Code, Also the Gui Is not visible and It is In The Diolauge Gui It is in a menu gui
Sure.MouseButton1Click:Connect(function()
game.StarterGui.QuestGui.NoQ:Destroy() <----------That is the destroy script
if script.Parent.Parent.Parent.TalkGui.TalkFrame.Dialogue.Text == "Hey kid Can you Do somthing for me?" then
local text = "Well i cant find My radio, last time i saw it I was at this abbandoned place"
local length = string.len(text)
for i = 1, length do
script.Parent.Parent.Parent.TalkGui.TalkFrame.Dialogue.Text = text:sub(1, i)
wait(0.04)
end
wait(0.5)
script.Parent.Parent.Parent.ButtonGui.ButtonFrame.Visible = false
script.Parent.Visible = false
end
end)
Also Ive Tried this
Local E = Game.StarterGui.QuestGui.NoQ
Sure.MouseButton1Click:Connect(function()
E.Destroy <---------------This is the destroy code
if script.Parent.Parent.Parent.TalkGui.TalkFrame.Dialogue.Text == "Hey kid Can you Do somthing for me?" then
local text = "Well i cant find My radio, last time i saw it I was at this abbandoned place"
local length = string.len(text)
for i = 1, length do
script.Parent.Parent.Parent.TalkGui.TalkFrame.Dialogue.Text = text:sub(1, i)
wait(0.04)
end
wait(0.5)
script.Parent.Parent.Parent.ButtonGui.ButtonFrame.Visible = false
script.Parent.Visible = false
end
end)
​
Could you please help i spent 3 hours on Looking for solutions
https://redd.it/l8zhfk
@r_lua
Lua and recursion - trying to determine similarity among strings
Hi, I am trying to group strings together if certain criteria are met. For instance I might have something liket1='cello' t2='cello dbl' t3='cello od' t4='cello od dbl' t5='cello od a' t6='cello od a dbl' t7='cello od a xx'
​
So per my rules, 'cello' and 'cello dbl' would be grouped together, because there is nothing else starting with 'cello dbl' that would enable 'cello dbl' to be grouped elsewhere.
Similarly, 'cello od' and 'cello od dbl' would be grouped together, because there is nothing else starting with 'cello od dbl' that would enable 'cello od dbl' to be grouped elsewhere.
And 'cello od a' and 'cello od a dbl' and 'cello od a xx' would be grouped together, because there is nothing else starting with 'cello od a' that would enable other groupings.
Hard to explain, but hopefully you see what I mean by these grouping rules.
I have a function that creates a similarity map among these strings, so that for any string, I know what other strings start off the same.
So,map['cello']['cello dbl'] = 'cello'
Likewise all other map['cello'[\] entries are equal to 'cello'map['cello dbl'][] entries are all empty (except map['cello dbl'\]['cello dbl'\] which is 'cello dbl'.map['cello od a'][] entries would equal 'cello od a' for strings 'cello od a dbl' and 'cello od a xx'
So I figured this amounts to some sort of recursion, so that I can determine if somewhere down the line, a string can be matched with something. My rule is, a string can't be matched to something, if that something also matches elsewhere. That way I ensure 'cello od a' does not match with 'cello od' and 'cello od dbl' because presence of 'cello od a dbl' (as well as 'cello od a xx') would force 'cello od a' to be grouped with them.
My recursion function to check all this isfunction does_word_match(similarity_matrix, someword)
local doesmatch=false
for commoni,commonv in pairs(similarity_matrix[someword]) doif commoni~= someword thenif commonv ~= '' thenmsg(3, someword..' and '..commoni..' have '..commonv..' in common\n')if not does_word_match(similarity_matrix, commoni) thendoesmatch=truemsg(3, 'a track containing '..someword..' can match to '..commoni..'\n')elsedoesmatch=falseendendend
end
if not doesmatch thenmsg(3, someword..' cannot match elsewhere\n')
end
return doesmatchend
I almost have this working, but I just can't figure out how to break out of the recursion once I have determined that a string will match somewhere. The function eventually exits, but seems to run too many times.
Anyway, I am not a programmer by profession, so I suspect I am doing something fundamentally wrong here, and was hoping based on the problem statement someone might know a better way, or might see immediately what I need to do to adjust this recursion function. I can't find much in google about lua and recursion, and examples I see seem to have return recursive_function sort of operation.
(sorry about formatting - can't seem to figure out how to get code looking normal...)
thanks!
https://redd.it/l7qhtm
@r_lua
Find integer in string, but make sure doesn't end with a non number
Hi,
I am trying to write a pattern that will extract 2 numbers from a string.
So with these sorts of inputs, I need to indicated outputss='A 11 22' -- 11, 22s='A 11' -- 11s='A 11 22b' -- 11s='A 11 23 B' -- 11, 23
In other words, I need to find 1 or 2 (or 0) integers
If I try thiss='A 11 34B'
with patternp='%s(%d*)%s(%d*)%s'n1,n2 = string.match(s,p)
then it returns nil, though I was expecting n1 to be 11.
Ideas?
https://redd.it/l67m0a
@r_lua