Partial Lua Binary Disassembler

local function TestFunction(a,b,c)
    local A = workspace:FindFirstChild("Nonexistent");
    return A;
end

local PrecompiledChunk = ("").dump(TestFunction);

-- Pre-compiled chunk reading
-- Lua binary chunk reading is simple for those who understand basic computer theory and bit marking.
-- The format of Lua 5.1's binary structure can be found:
--      http://luaforge.net/docman/83/98/ANoFrillsIntroToLua51VMInstructions.pdf
local Lexer = 1;

function ReadNextByte()
    local Byte = PrecompiledChunk:sub(Lexer,Lexer):byte();
    Lexer = Lexer + 1
    return Byte;
end

function ReadNextByte2()
    local B1 = ReadNextByte();
    local B2 = ReadNextByte();
    return (B2 * 256) + B1
end

function ReadNextByte4()
    local B1 = ReadNextByte();
    local B2 = ReadNextByte();
    local B3 = ReadNextByte();
    local B4 = ReadNextByte();
    return (B4 * 16777216 ) + (B3 * 65536 ) + (B2 * 256) + B1
end

function ReadNextByte8()
    local B1 = ReadNextByte();
    local B2 = ReadNextByte();
    local B3 = ReadNextByte();
    local B4 = ReadNextByte();
    local B5 = ReadNextByte();
    return (B5 * 4294967296 ) + (B4 * 16777216 ) + (B3 * 65536 ) + (B2 * 256) + B1
end

function ReadString(LengthOfString)
    local String = PrecompiledChunk:sub(Lexer, Lexer + (LengthOfString - 1));
    Lexer = Lexer + LengthOfString
end

-- Lua Header
-- The Lua header is always 12 bytes, no matter what.
local Identification = ReadString(4);
local VersionNumber = ReadNextByte();
local FormatVersion = ReadNextByte();
local EndianFlag = ReadNextByte();
local SizeOfInt = ReadNextByte();
local Size_T = ReadNextByte();
local SizeOfInstruction = ReadNextByte() -- Lua Assembly OpCode sizes
local SizeOfLuaNumber = ReadNextByte();
local IntFlag = ReadNextByte();
print(SizeOfInt, Size_T, SizeOfInstruction); -- Should print three 4's. This means it is correct.
-- That totals to 12 bytes. Success

-- The next step is to get the source name. The size of the string is defined by Size_T. It is defaulted to 4.
-- Obtain the string size like this:
local SizeOfSourceName = (Size_T == 4) and ReadNextByte4() or ReadNextByte8();
print(SizeOfSourceName);

-- With the size of the string, loop through each position by 1 byte
local SourceName = "";
for i = 1, SizeOfSourceName do
    SourceName = SourceName .. ("").char(ReadNextByte());
end
print(SourceName); -- Should print the source name of this script (about the same as script:GetFullName());

-- The next two function proto's are the line definitions of the ORIGINAL dumped function.
-- It is optional debug data. The size of the intenger in the binary dump are define by SizeOfInt (default 4).
local LineDefined = (SizeOfInt == 4) and ReadNextByte4() or ReadNextByte8();
local LineEnded = (SizeOfInt == 4) and ReadNextByte4() or ReadNextByte8();
print(LineDefined, LineEnded);

-- The following is the number of upvalues the function had, and number of parameters:
local NumOfUpvalues = ReadNextByte();
local NumOfParameters = ReadNextByte();
print(NumOfUpvalues, NumOfParameters);