[luarrow] Pipeline-operator and Haskell-style function composition, for Lua (like: `x |> h |> g |> f` and `f . g . h $ x`)

Hey r/lua!
I've been working on a library that brings functional programming elegance to Lua through operator overloading.

**What it does:**
Instead of writing nested function calls like `f(g(h(x)))`, we can write:

* Pipeline-style:
* `x % arrow(h) ^ arrow(g) ^ arrow(f)`
* Like `x |> h |> g |> f` in other languages
* Haskell-style:
* `fun(f) * fun(g) * fun(h) % x`
* Like `f . g . h $ x` in Haskell

**Purpose:**
Clean coding style, improved readability, and exploration of Lua's potential!

**Quick example:**
This library provides `arrow` and `fun` functions.

`arrow` is for pipeline-style composition using the `^` operator:

local arrow = require('luarrow').arrow

local _ = 42
% arrow(function(x) return x - 2 end)
^ arrow(function(x) return x * 10 end)
^ arrow(function(x) return x + 1 end)
^ arrow(print) -- 401

`arrow` is good at processing and calculating all at once, as described above.

The `fun` is suitable for function composition. Using the `*` operator to concatenate functions:

local add_one = function(x) return x + 1 end
local times_ten = function(x) return x * 10 end
local minus_two = function(x) return x - 2 end
local square = function(x) return x * x end

-- Function composition!
local pipeline = fun(square) * fun(add_one) * fun(times_ten) * fun(minus_two)

print(pipeline % 42) -- 160801

In Haskell culture, this method of `pipeline` composition is called `Point-Free Style'. It is very suitable when there is no need to wrap it again in`function\` syntax or lambda expressions.

**Performance:**
In LuaJIT environments, pre-composed functions have virtually **no overhead compared to pure Lua**.
Even Lua, which is not LuaJIT, performs comparably well for most applications.
Please visit [https://github.com/aiya000/luarrow.lua/blob/main/doc/examples.md#-performance-considerations](https://github.com/aiya000/luarrow.lua/blob/main/luarrow.lua/doc/examples.md#-performance-considerations)

**Links:**

* GitHub: [https://github.com/aiya000/luarrow.lua](https://github.com/aiya000/luarrow.lua)
* Install: luarocks install luarrow

I'd love to hear your thoughts and feedback!
Is this something you'd find useful in your Lua projects?

https://redd.it/1ojwll9
@r_lua

Simple machine learning model using Lua

Hello r/lua! I haven't been here in a long time, and I've been making either stupid and cool stuff in the meantime. I found this cool library on GitHub, it's super easy to use, and I'd want to share the things I've made with it! It's nothing much but I think it's really cool because now I can do something interesting with Lua! It's a cool noscripting language and I hope more things like this happen in the future! Link to library:

[https://github.com/Nikaoto/nn.lua](https://github.com/Nikaoto/nn.lua)

Simple XOR model:

local nn = require("nn") -- import neural network library into your noscript

local net = nn.new_neural_net({
neuron_counts = {2, 10, 1},
act_fns = {'sigmoid', 'sigmoid'}
})

-- initalize neural network with 2 input, 10 hidden, and 1 output neurons, respectively

local training_data_xor = {
-- Format: {inputs = {A, B}, output = {Y}}

-- Case 1: 0 XOR 0 = 0
{inputs = {0.0, 0.0}, outputs = {0.0}},

-- Case 2: 0 XOR 1 = 1
{inputs = {0.0, 1.0}, outputs = {1.0}},

-- Case 3: 1 XOR 0 = 1
{inputs = {1.0, 0.0}, outputs = {1.0}},

-- Case 4: 1 XOR 1 = 0
{inputs = {1.0, 1.0}, outputs = {0.0}}
}

nn.train(net, training_data_xor, {
epochs = 1000,
learning_rate = 0.1
})

-- train the model

local outputs = nn.feedforward(net, {inputs={1, 0}})
print(outputs[1])

-- Expected 0
local out_00 = nn.feedforward(net, {inputs={0.0, 0.0}})
print(string.format("0 XOR 0: %.4f (Expected: 0)", out_00[1]))

-- Expected 1
local out_01 = nn.feedforward(net, {inputs={0.0, 1.0}})
print(string.format("0 XOR 1: %.4f (Expected: 1)", out_01[1]))

-- Expected 1
local out_10 = nn.feedforward(net, {inputs={1.0, 0.0}})
print(string.format("1 XOR 0: %.4f (Expected: 1)", out_10[1]))

-- Expected 0
local out_11 = nn.feedforward(net, {inputs={1.0, 1.0}})
print(string.format("1 XOR 1: %.4f (Expected: 0)", out_11[1]))

https://redd.it/1okasgq
@r_lua

Is GLua same as Roblox Lua?

I go to have a look at roblox studio the lua. I've been think that GLua is same programing language as roblox because this two has same code like

Gmod is

(Print hello world)

Roblox is this too.

(Print hellow world)

So i might be think if a one person has the lua experience on roblox? That was mean he is understand how to create a GLua for addons

https://redd.it/1okw1n6
@r_lua

Does anyone else use lua as their main language for system automation and shell noscripting?

it's no secret that Lua is heavily underrated. ironically, i used to be against lua until i understood how nifty it is as a language. i formerly thought that one had to use index or metatable to create objects, only to find out that i could do this



```

function NameOfObject(instanceVariable1, instanceVariable2)

return{

method1 = function(self)

end,



method2 = function(self)

end,



method3 = function(self)

end,

}

end

```

and just like that it overtook the appreciation i had for how objects can be created in other languages.

in a less subjective sense, however, given how ridiculuously fast lua is compared to the bulk of languages that are interpreted, i committed to it for all my noscripting needs.

lua has now become my premier choice for automating anything related to my environment: my file system, my window manager, and even my system settings. it also greatly helps that i can automate repetitive and tedious text editing in neovim with lua as well.

i formerly used python for my noscripting needs, and in retrospect, it's rather comical to me how poor python is as a noscripting language compared to lua; it's a night and day difference. i can always trust lua for a startup time that is as good as instantaneous, whereas such a thing would be a fool's game in python.

granted, python does have all the abstractions one can hope for, but for system tasks, it's just outright overkill. one does not need a gazillian abstractions for system admin or shell noscripting needs

anyways, i've rambled long enough. is there anyone else that uses lua for shell noscripting needs and system automation, as opposed to roblox, C programming, game dev, and other low level tasks?



https://redd.it/1olcmrc
@r_lua

What game engine should i choose?

what game engine that is not a library, framework or Roblox Studio should i use

https://redd.it/1olhgl9
@r_lua

Luraph deobfuscator

Any working deobfuscator for luraph ?

https://redd.it/1olqhjc
@r_lua

Question about string.match() and string.gsub()

I'm playing around with strings a bit and I got a weird result that I'd like an explanation for if possible.

Below, when I just run string.match on the test string, I get a string with the letter e at the end. But when I run it through gsub to strip the spaces, the e becomes a 0. Why is that?

> test_string = 'words_here.test.test'
> string.match(test_string, "(.+)%..+(e)")
words_here.test e
> string.match(test_string, "(.+)%..+(e)"):gsub("%s+", "")
words_here.test 0
> string.gsub(string.match(test_string, "(.+)%..+(e)"), "%s+", "")
words_here.test 0

EDIT: It also doesn't strip the spaces...

https://redd.it/1olycge
@r_lua

Hey so this game uses lua and some custom code to this character,i need help making so whenever i say an specific word it does something,so far i got this noscript working but only for the "hi" part (someone shared an noscript with me)

https://redd.it/1oma091
@r_lua

Problem with MoonSec V3

https://redd.it/1omaxzh
@r_lua

car flipping upside down only ingame and only on pc, in roblox studio everything is good

i used a Jeep free model from the toolbox, you must know what is this model, the code is:

--Scripted by DermonDarble



local car = noscript.Parent

local stats = car.Configurations

local Raycast = require(noscript.RaycastModule)



local mass = 0



for i, v in pairs(car:GetChildren()) do

if v:IsA("BasePart") then

mass = mass + (v:GetMass() * 196.2)

end

end



local bodyPosition = car.Chassis.BodyPosition

local bodyGyro = car.Chassis.BodyGyro



--local bodyPosition = Instance.new("BodyPosition", car.Chassis)

--bodyPosition.MaxForce = Vector3.new()

--local bodyGyro = Instance.new("BodyGyro", car.Chassis)

--bodyGyro.MaxTorque = Vector3.new()



local function UpdateThruster(thruster)

-- Raycasting

local hit, position = Raycast.new(thruster.Position, thruster.CFrame:vectorToWorldSpace(Vector3.new(0, -1, 0)) * stats.Height.Value) --game.Workspace:FindPartOnRay(ray, car)

local thrusterHeight = (position - thruster.Position).magnitude



-- Wheel

local wheelWeld = thruster:FindFirstChild("WheelWeld")

wheelWeld.C0 = CFrame.new(0, -math.min(thrusterHeight, stats.Height.Value * 0.8) + (wheelWeld.Part1.Size.Y / 2), 0)

-- Wheel turning

local offset = car.Chassis.CFrame:inverse() * thruster.CFrame

local speed = car.Chassis.CFrame:vectorToObjectSpace(car.Chassis.Velocity)

if offset.Z < 0 then

local direction = 1

if speed.Z > 0 then

direction = -1

end

wheelWeld.C0 = wheelWeld.C0 * CFrame.Angles(0, (car.Chassis.RotVelocity.Y / 2) * direction, 0)

end



-- Particles

if hit and thruster.Velocity.magnitude >= 5 then

wheelWeld.Part1.ParticleEmitter.Enabled = true

else

wheelWeld.Part1.ParticleEmitter.Enabled = false

end

end



car.DriveSeat.Changed:connect(function(property)

if property == "Occupant" then

if car.DriveSeat.Occupant then

car.EngineBlock.Running.Pitch = 1

car.EngineBlock.Running:Play()

local player = game.Players:GetPlayerFromCharacter(car.DriveSeat.Occupant.Parent)

if player then

car.DriveSeat:SetNetworkOwner(player)

local localCarScript = noscript.LocalCarScript:Clone()

localCarScript.Parent = player.PlayerGui

localCarScript.Car.Value = car

localCarScript.Disabled = false

end

else

car.EngineBlock.Running:Stop()

end

end

end)



--spawn(function()

while true do

game:GetService("RunService").Stepped:wait()

for i, part in pairs(car:GetChildren()) do

if `part.Name` == "Thruster" then

UpdateThruster(part)

end

end

if car.DriveSeat.Occupant then

local ratio = car.DriveSeat.Velocity.magnitude / stats.Speed.Value

car.EngineBlock.Running.Pitch = 1 + ratio / 4

bodyPosition.MaxForce = Vector3.new()

bodyGyro.MaxTorque = Vector3.new()

else

local hit, position, normal = Raycast.new(car.Chassis.Position, car.Chassis.CFrame:vectorToWorldSpace(Vector3.new(0, -1, 0)) * stats.Height.Value)

if hit and hit.CanCollide then

bodyPosition.MaxForce = Vector3.new(mass / 5, math.huge, mass / 5)

bodyPosition.Position = (CFrame.new(position, position + normal) * CFrame.new(0, 0, -stats.Height.Value + 0.5)).Position

bodyGyro.MaxTorque = Vector3.new(math.huge, 0, math.huge)

bodyGyro.CFrame = CFrame.new(position, position + normal) * CFrame.Angles(-math.pi/2, 0, 0)

else

bodyPosition.MaxForce = Vector3.new()

bodyGyro.MaxTorque = Vector3.new()

end

end

end

--end)


ask in the comments for more info

i alredy lowered down the speed of the car and turn speed too, to avoid them falling upside down, but its still going crazy on slopes

https://redd.it/1on2tkz
@r_lua

I wrote a framework to build VST Plugins using Lua!

This is a Stereo Imager VST plugin that can be used to increase or decrease the stereo field.

This is a Physically modeled amplifier VST plugin

I found it difficult to iterate and coordinate changes efficiently with C++ compile times, even when they were minimized.

So I decided to build a framework, using C++ on the back-end, and writing a Lua-library for hot-reloaded application setup, resource management, UI, interactivity and even optimized DSP!

https://redd.it/1ongpry
@r_lua

I think I'm misunderstanding the return function
https://redd.it/1onmn3h
@r_lua

Node.js bindings for Lua — lua-state

I’ve recently published an open-source package called lua-state.

It provides native Lua bindings for Node.js — you can create Lua virtual machines from JavaScript, run Lua code, exchange values between JS and Lua, and even use prebuilt binaries (no manual compilation required for Lua 5.4.8).

Supports Lua 5.1–5.4 and LuaJIT.

Source code: github.com/quaternion/node-lua-state

If you’re interested in embedding Lua into JS applications or experimenting with Lua noscripting from Node, I’d really appreciate any feedback or thoughts.

https://redd.it/1oo3cib
@r_lua

LÖVE - Free 2D Game Engine
https://love2d.org/

https://redd.it/1oou0qr
@r_lua

How bad is it to use local self = {} instead of the vastly popular local M = {}

I've just start learning lua mostly for using it in neovim. As I expand my knowledge to writing bigger modules, I noticed that most Lua tutorials use the following convention:

local M = {}

<..code..>

return M

However, to my naive self, self seems a lot better. Consider:

local M = {}
M.bar = 2
function M:foo()
    return self.bar + 1
end
return M

vs

local self = {}
self.bar = 2
function self.foo()
    return self.bar + 1
end
return self

1. Notice how foo continues using self so that it "feels" like the former (perhaps more OOP-ish) way of doing things.
2. It helps everywhere you want to pass foo as a callback in other modules:

p = require('a.b.mymodule')

some_function({callback = function() p:foo() end})
---vs (IMO much better)
some_function({callback = p.foo})

So I only see advantages to doing it the local self = {} way. Why is this not popular or not recommended? I'm assuming it'll break something but not sure what.

https://redd.it/1op9cnw
@r_lua

I'm developing Sandman, an HTTP focussed, Lua based Notebook-style app, (more than a Postman alternative)
https://redd.it/1opca0h
@r_lua

Interactive fractal graphics zoom (Love2d)
https://slicker.me/lua/fractal.html

https://redd.it/1opdsai
@r_lua

Made this GUI Library thing for LOVE2D

https://github.com/TookeyPower/TookeyPower-GUI-LibraryThing/tree/main
LMK what would be cool to add or what could be improved

https://redd.it/1opm94y
@r_lua

Need help with images

I am incredibly new to Lua. Like so very very new. like i know nothing. I am learning to code, my programs are love2d to load the game and visual studio to write it

I have the image i want in the file (as seen below, ignore the name for it i was tired.), but im not sure how to load it onto the actual screen of the game. Ive tried loadfile(yummy.jpg, bt, any) after the function with an ending but nothing happens. help is very much appreciated :)

https://preview.redd.it/8wfgr3sxs30g1.png?width=175&format=png&auto=webp&s=935f048738bf34fe2d4be93e90d078964770d91c



https://redd.it/1os1ime
@r_lua

Desobfuscate Lua noscript

Who can help me to desobfuscate this noscript: https://raw.githubusercontent.com/ZutixHub/Premium/refs/heads/main/HouseCloner.lua

https://redd.it/1osjvae
@r_lua

Syntax conventions, string.foo(bar) vs bar:foo()

I'm primarily a Python programmer but I've been learning Lua for various reasons and I am coming to appreciate its sleek nature the more I use it.

That said, I'm grappling with the different syntax options that Lua provides. In the Pythonic mantra, the line There should be one-- and preferably only one --obvious way to do it. comes to mind; while it is nice to have options I feel like I should choose one way or another and stick to it. Is this how Lua programmers typically operate?

If I were to stick with one, which to do? Again referencing the Pythonic way, we have Explicit is better than implicit. and Sparse is better than dense. and Readability counts., which to me would point to using string.foo(bar) instead of the : syntactic sugar, but it also isn't quite as compact.

What are your thoughts? Am I just overthinking things and applying Pythonic logic where I shouldn't? How do Lua programmers typically write their code?

https://redd.it/1osu6zj
@r_lua