Dalbit

Dalbit(달빛) is a Luau-to-Lua transpiler, designed specifically for Lua 5.3.

Note

This project is still in W.I.P

TO-DOs

• Implement CLI.
• Implement basic transpilation process using darklua and full-moon.
• Implement modifiers (such as converting number literals and generalized iterations)
• Implement basic lua polyfills.
• Add tests for polyfills.
• Add tests for transpilation. (to ensure the same results in lua and luau)
• Add tests for dalbit internally.
• Add logging for dalbit internally for debug.
• convert_bit32 modifier now converts bit32.btest.
• Add comments for docs and code readability. (WIP)
• Optimize polyfill.

Installation

Using Cargo (from crates.io)

cargo install dalbit --locked

Usage

init

Initializes dalbit manifest file in the current path.

dalbit init

fetch

Fetches and updates lua polyfills.

• This polyfill can be found here.

dalbit fetch

transpile

Transpiles luau code to lua code.

dalbit transpile [input] [output]

Example

dalbit.toml

file_extension = "lua"
target_version = "lua53"
minify = true

[modifiers]
convert_bit32 = true

[globals]

inputs/input.luau

local log = math.log
local floor = math.floor
local x = bit32
local band = x.band
local rshift = x.rshift
local lshift = x.lshift
local bnot = x.bnot
local bor = x.bor
local t = table.create(1)

local function byteswap(n: number): number
	return bor(bor(bor(lshift(n, 24), band(lshift(n, 8), 0xff0000)), band(rshift(n, 8), 0xff00)), rshift(n, 24))
end

print(byteswap(5))
print(log(5))
print(floor(0.5))
print(t)

outputs/output.luau

local math=require'./__polyfill__'.math local table=require'./__polyfill__'.table local io=nil local module=nil local package=nil local dofile=nil local loadfile=nil local load=nil local log=math.log
local floor=math.floor
 do
end  do
end  do
end  do  end  do

end  do
end local t=table.create(1)

local function byteswap(n)
return ((((((((n<<24)&0xFFFFFFFF)|((((n<<8)&0xFFFFFFFF)&0xff0000)&0xFFFFFFFF))&0xFFFFFFFF)|((((n>>8)&0xFFFFFFFF)&0xff00)&0xFFFFFFFF))&0xFFFFFFFF)|((n>>24)&0xFFFFFFFF))&0xFFFFFFFF)
end

print(byteswap(5))
print(log(5))
print(floor(0.5))
print(t)

How does it work?

• Dalbit actively utilizes darklua and full-moon to transform lua scripts.

Why darklua-demo over darklua?

• darklua-demo is a temporary fork to work properly with dal.
• darklua-demo will be replaced by official darklua once darklua released with important features to work properly with dal.

Special Thanks

• seaofvoices/darklua - Providing important and cool lua mutating rules.
• Kampfkarren/full-moon - A lossless Lua parser.

Trivia

The name of this project, Dalbit, translates to "moonshine" in Korean.