Variable and Symbol Renaming in Lua/Luau

local _0 = 10
local _1 = "hello"
local function _2(_3)
    return _3 + _0
end

local _0x1A = 10
local _0x2B = "hello"
local function _0x3C(_0x4D)
    return _0x4D + _0x1A
end

local О = 10       -- Cyrillic Capital Letter O (U+041E)
local а = "hello"  -- Cyrillic Small Letter A (U+0430)
local function ƒ(x)
    return x + О
end

local _if = 10
local _end = "hello"
local _do = true
local function _while(_then)
    return _then + _if
end

local kx9mP2vL = 10
local Qr4Tw8zN = "hello"
local function bJ3hF7dC(aX5kL2pR)
    return aX5kL2pR + kx9mP2vL
end

local _a = 10

local function outer()
    local _a = "shadow"
    local function inner()
        local _a = true
        return _a
    end
    return inner()
end

local x = 10          -- outer x

local function f()
    print(x)          -- prints 10 (upvalue)
    local x = 20      -- inner x shadows outer x
    print(x)          -- prints 20
end

f()
print(x)              -- prints 10

-- Original
local playerCount = 5

local function getCount()
    return playerCount
end

local function setCount(n)
    local playerCount = n
    return playerCount
end

-- INCORRECTLY RENAMED (broken)
local _a = 5

local function _b()
    return _a
end

local function _c(_d)
    local _a = _d      -- ERROR: shadows _a but getCount still references outer _a
    return _a
end

-- CORRECTLY RENAMED
local _a = 5

local function _b()
    return _a         -- binds to outer _a
end

local function _c(_d)
    local _e = _d     -- separate name for inner local
    return _e
end

-- Pseudocode for scope-aware renaming
scopes = [{}]  -- stack with global scope at bottom

function enterScope()
    table.insert(scopes, {})
end

function leaveScope()
    table.remove(scopes)
end

function declare(name, generated)
    scopes[#scopes][name] = generated
end

function resolve(name)
    for i = #scopes, 1, -1 do
        if scopes[i][name] then
            return scopes[i][name]
        end
    end
    return name  -- global, leave unchanged
end

-- Original
local function makeCounter()
    local count = 0
    return function()
        count = count + 1
        return count
    end
end

-- Correctly renamed
local function _a()
    local _b = 0
    return function()
        _b = _b + 1
        return _b
    end
end

-- Original
local function calculate(a, b, operation)
    if operation == "add" then
        return a + b
    elseif operation == "mul" then
        return a * b
    end
end

-- Renamed
local function _a(_b, _c, _d)
    if _d == "add" then
        return _b + _c
    elseif _d == "mul" then
        return _b * _c
    end
end

local function _a(...)
    local _b = {...}
    -- work with _b instead of ...
end

-- Original
function Player:getHealth()
    return self.health
end

-- Safe rename (preserving colon)
function _a:_b()
    return _c.health
end

-- Also safe (converting to dot)
function _a._b(_c)
    return _c.health
end

-- Original
local config = {
    maxPlayers = 20,
    gameMode = "capture",
    timeLimit = 300
}

local max = config.maxPlayers
local mode = config["gameMode"]

-- Renamed
local _a = {
    _b = 20,
    _c = "capture",
    _d = 300
}

local _e = _a._b
local _f = _a["_c"]

-- Original
local API = {}
API.baseUrl = "https://api.example.com"
API.version = "v2"
API.timeout = 30

function API:request(endpoint)
    local url = self.baseUrl .. "/" .. self.version .. endpoint
    print("Requesting", url, "with timeout", self.timeout)
    return url
end

return API

-- Renamed
local _a = {}
_a._b = "https://api.example.com"
_a._c = "v2"
_a._d = 30

function _a:_e(_f)
    local _g = _c._b .. "/" .. _c._c .. _f
    print("Requesting", _g, "with timeout", _c._d)
    return _g
end

return _a

-- Original
local function createMultiplier(factor)
    local multiplier = factor
    return function(value)
        return value * multiplier
    end
end

local double = createMultiplier(2)
print(double(5))  -- 10

-- Renamed
local function _a(_b)
    local _c = _b
    return function(_d)
        return _d * _c
    end
end

local _e = _a(2)
print(_e(5))  -- 10

-- Original Luau
local x: number = 5
local y: string = "hello"
local function add(a: number, b: number): number
    return a + b
end

-- After stripping types, then renaming
local _a = 5
local _b = "hello"
local function _c(_d, _e)
    return _d + _e
end

-- Original module
local MyModule = {}

function MyModule.doSomething()
    print("done")
end

return MyModule

-- Option 3: indirection table
local _a = {}

function _a._b()
    print("done")
end

return {
    doSomething = _a._b  -- external name preserved, internal name obfuscated
}