refactoring: switched to match/case

wow! python actually added switch cases! too bad this is just syntax sugar...

.gitignore

@@ -1,2 +1,3 @@
 example.*
 __pycache__
+NOTES.md

README.md

@@ -12,51 +12,95 @@ Lua has a relatively small instruction set (only 38 different opcodes!). This ma
 
 ```sh
 > cat example.lua && luac5.1 -o example.luac example.lua
-local total = 0
+local printMsg = function(append)
+    local tbl = {"He", "llo", " ", "Wo"}
+    local str = ""
 
-for i = 0, 9, 1 do
+    for i = 1, #tbl do
-    total = total + i
+        str = str .. tbl[i]
-    print(total)
+    end
+
+    print(str .. append)
 end
+
+printMsg("rld!")
 > python main.py example.luac
 example.luac
 
 ==== [[example.lua's constants]] ====
 
-0: [NUMBER] 0.0
+0: [STRING] rld!
-1: [NUMBER] 9.0
-2: [NUMBER] 1.0
-3: [STRING] print
 
 ==== [[example.lua's locals]] ====
 
-R[0]: total
+R[0]: printMsg
-R[1]: (for index)
-R[2]: (for limit)
-R[3]: (for step)
-R[4]: i
 
 ==== [[example.lua's dissassembly]] ====
 
-[  0]      LOADK :   R[0]   K[0]               ; load 0.0 into R[0]
+[  0]    CLOSURE :   R[0]      0               ; 
-[  1]      LOADK :   R[1]   K[0]               ; load 0.0 into R[1]
+[  1]       MOVE :      1      0      0        ; move R[0] into R[1]
-[  2]      LOADK :   R[2]   K[1]               ; load 9.0 into R[2]
+[  2]      LOADK :   R[2]   K[0]               ; load "rld!" into R[2]
-[  3]      LOADK :   R[3]   K[2]               ; load 1.0 into R[3]
+[  3]       CALL :      1      2      1        ; 
-[  4]    FORPREP :   R[1]      4               ; 
+[  4]     RETURN :      0      1      0        ; 
-[  5]        ADD :   R[0]   R[0]   R[4]        ; add R[4] to R[0], place into R[0]
-[  6]  GETGLOBAL :   R[5]   K[3]               ; move _G["print"] into R[5]
-[  7]       MOVE :      6      0      0        ; move R[0] into R[6]
-[  8]       CALL :      5      2      1        ; 
-[  9]    FORLOOP :   R[1]     -5               ; 
-[ 10]     RETURN :      0      1      0        ; 
 
-==== [[example.lua's decompiled source]] ====
+==== [[example.lua's protos]] ====
 
-local total = 0.0
+
-for i = 0.0, 9.0, 1.0 do
+==== [['s constants]] ====
-    total = (total + i)
+
-    print(total)
+0: [STRING] He
+1: [STRING] llo
+2: [STRING]  
+3: [STRING] Wo
+4: [STRING] 
+5: [NUMBER] 1.0
+6: [STRING] print
+
+==== [['s locals]] ====
+
+R[0]: append
+R[1]: tbl
+R[2]: str
+R[3]: (for index)
+R[4]: (for limit)
+R[5]: (for step)
+R[6]: i
+
+==== [['s dissassembly]] ====
+
+[  0]   NEWTABLE :      1      4      0        ; 
+[  1]      LOADK :   R[2]   K[0]               ; load "He" into R[2]
+[  2]      LOADK :   R[3]   K[1]               ; load "llo" into R[3]
+[  3]      LOADK :   R[4]   K[2]               ; load " " into R[4]
+[  4]      LOADK :   R[5]   K[3]               ; load "Wo" into R[5]
+[  5]    SETLIST :      1      4      1        ; 
+[  6]      LOADK :   R[2]   K[4]               ; load "" into R[2]
+[  7]      LOADK :   R[3]   K[5]               ; load 1 into R[3]
+[  8]        LEN :      4      1      0        ; 
+[  9]      LOADK :   R[5]   K[5]               ; load 1 into R[5]
+[ 10]    FORPREP :   R[3]      3               ; 
+[ 11]       MOVE :      7      2      0        ; move R[2] into R[7]
+[ 12]   GETTABLE :   R[8]      1   R[6]        ; 
+[ 13]     CONCAT :      2      7      8        ; concat 2 values from R[7] to R[8], store into R[2]
+[ 14]    FORLOOP :   R[3]     -4               ; 
+[ 15]  GETGLOBAL :   R[3]   K[6]               ; move _G["print"] into R[3]
+[ 16]       MOVE :      4      2      0        ; move R[2] into R[4]
+[ 17]       MOVE :      5      0      0        ; move R[0] into R[5]
+[ 18]     CONCAT :      4      4      5        ; concat 2 values from R[4] to R[5], store into R[4]
+[ 19]       CALL :      3      2      1        ; 
+[ 20]     RETURN :      0      1      0        ; 
+
+==== [[example.lua's pseudo-code]] ====
+
+local printMsg = function(append)
+    local tbl = {"He", "llo", " ", "Wo", }
+    local str = ""
+    for i = 1, #tbl, 1 do
+        str = str .. tbl[i]
+    end
+    print(str .. append)
 end
 
+printMsg("rld!")
 
 ```

lparser.py

@@ -6,9 +6,6 @@
     An experimental bytecode decompiler.
 '''
 
-from operator import concat
-from subprocess import call
-from xmlrpc.client import Boolean
 from lundump import Chunk, Constant, Instruction, Opcodes, whichRK, readRKasK
 
 class _Scope:
@@ -30,14 +27,19 @@ class _Line:
         self.scope = scope
 
 def isValidLocal(ident: str) -> bool:
-    for c in ident:
+    # has to start with an alpha or _
-        if c not in "abcdefghijklmnopqrstuvwxyz1234567890_":
+    if ident[0] not in "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_":
+        return False
+
+    # then it can be alphanum or _
+    for c in ident[1:]:
+        if c not in "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890_":
             return False
 
     return True
 
 class LuaDecomp:
-    def __init__(self, chunk: Chunk):
+    def __init__(self, chunk: Chunk, headChunk: bool = True, scopeOffset: int = 0):
         self.chunk = chunk
         self.pc = 0
         self.scope: list[_Scope] = []
@@ -46,6 +48,8 @@ class LuaDecomp:
         self.locals = {}
         self.traceback = {}
         self.unknownLocalCount = 0
+        self.headChunk = headChunk
+        self.scopeOffset = scopeOffset # number of scopes this chunk/proto is in
         self.src: str = ""
 
         # configurations!
@@ -55,6 +59,20 @@ class LuaDecomp:
 
         self.__loadLocals()
 
+        if not self.headChunk:
+            functionProto = "function("
+
+            # define params
+            for i in range(self.chunk.numParams):
+                # add param to function prototype (also make a local in the register if it doesn't exist)
+                functionProto += ("%s, " if i+1 < self.chunk.numParams else "%s") % self.__makeLocalIdentifier(i)
+
+                # mark local as defined
+                self.__addSetTraceback(i)
+            functionProto += ")"
+
+            self.__startScope(functionProto, 0, len(self.chunk.instructions))
+
         # parse instructions
         while self.pc < len(self.chunk.instructions):
             self.parseInstr()
@@ -63,12 +81,18 @@ class LuaDecomp:
             # end the scope (if we're supposed too)
             self.__checkScope()
 
-        print("\n==== [[" + str(self.chunk.name) + "'s decompiled source]] ====\n")
+        if not self.headChunk:
+            self.__endScope()
+
+    def getPseudoCode(self) -> str:
+        fullSrc = ""
 
         for line in self.lines:
             if self.annotateLines:
-                print("-- PC: %d to PC: %d" % (line.startPC, line.endPC))
+                fullSrc += "-- PC: %d to PC: %d\n" % (line.startPC, line.endPC)
-            print(((' ' * self.indexWidth) * line.scope) + line.src)
+            fullSrc += ((' ' * self.indexWidth) * (line.scope + self.scopeOffset)) + line.src + "\n"
+
+        return fullSrc
 
     # =======================================[[ Helpers ]]=========================================
 
@@ -121,7 +145,7 @@ class LuaDecomp:
         self.src = ""
 
     # walks traceback, if local wasn't set before, the local needs to be defined
-    def __needsDefined(self, reg) -> Boolean:
+    def __needsDefined(self, reg) -> bool:
         for _, trace in self.traceback.items():
             if reg in trace.sets:
                 return False
@@ -147,7 +171,7 @@ class LuaDecomp:
         # if the top indx is a local, get it
         return self.locals[indx] if indx in self.locals else self.top[indx]
 
-    def __setReg(self, indx: int, code: str) -> None:
+    def __setReg(self, indx: int, code: str, forceLocal: bool = False) -> None:
         # if the top indx is a local, set it
         if indx in self.locals:
             if self.__needsDefined(indx):
@@ -155,10 +179,9 @@ class LuaDecomp:
             else:
                 self.__addExpr(self.locals[indx] + " = " + code)
                 self.__endStatement()
-        elif self.aggressiveLocals: # 'every register is a local!!'
+        elif self.aggressiveLocals or forceLocal: # 'every register is a local!!'
             self.__newLocal(indx, code)
 
-
         self.__addSetTraceback(indx)
         self.top[indx] = code
 
@@ -176,7 +199,6 @@ class LuaDecomp:
         return self.locals[indx]
 
     def __newLocal(self, indx: int, expr: str) -> None:
-        # TODO: grab identifier from chunk(?)
         self.__makeLocalIdentifier(indx)
 
         self.__addExpr("local " + self.locals[indx] + " = " + expr)
@@ -202,12 +224,15 @@ class LuaDecomp:
         self.__addExpr("end")
         self.scope.pop()
 
+        self.__endStatement()
+
     # =====================================[[ Instructions ]]======================================
 
     def __emitOperand(self, a: int, b: str, c: str, op: str) -> None:
         self.__setReg(a, "(" + b + op + c + ")")
 
-    def __compJmp(self, op: str):
+    # handles conditional jumps
+    def __condJmp(self, op: str, rkBC: bool = True):
         instr = self.__getCurrInstr()
         jmpType = "if"
         scopeStart = "then"
@@ -230,7 +255,13 @@ class LuaDecomp:
             self.__addExpr("%s not " % jmpType)
         else:
             self.__addExpr("%s " % jmpType)
-        self.__addExpr(self.__readRK(instr.B) + op + self.__readRK(instr.C) + " ")
+
+        # write actual comparison
+        if rkBC:
+            self.__addExpr(self.__readRK(instr.B) + op + self.__readRK(instr.C) + " ")
+        else: # just testing rkB
+            self.__addExpr(op + self.__readRK(instr.B))
+
         self.pc += 1 # skip next instr
         if scopeStart:
             self.__startScope("%s " % scopeStart, self.pc - 1, jmp)
@@ -256,102 +287,160 @@ class LuaDecomp:
         else:
             return self.__getReg(rk)
 
+    # walk & peak ahead NEWTABLE
+    def __parseNewTable(self, indx: int):
+        # TODO: parse SETTABLE too?
+        tblOps = [Opcodes.LOADK, Opcodes.SETLIST]
+
+        instr = self.__getNextInstr()
+        cachedRegs = {}
+        tbl = "{"
+        while instr.opcode in tblOps:
+            if instr.opcode == Opcodes.LOADK: # operate on registers
+                cachedRegs[instr.A] = self.chunk.getConstant(instr.B).toCode()
+            elif instr.opcode == Opcodes.SETLIST:
+                numElems = instr.B
+
+                for i in range(numElems):
+                    tbl += "%s, " % cachedRegs[instr.A + i + 1]
+                    del cachedRegs[instr.A + i + 1]
+
+            self.pc += 1
+            instr = self.__getNextInstr()
+        tbl += "}"
+
+        # i use forceLocal here even though i don't know *for sure* that the register is a local.
+        # this does help later though if the table is reused (which is 99% of the time). the other 1%
+        # only affects syntax and may look a little weird but is fine and equivalent non-the-less
+        self.__setReg(indx, tbl, forceLocal=True)
+        self.__endStatement()
+
+        # if we have leftovers... oops, set those
+        for i, v in cachedRegs.items():
+            self.__setReg(i, v)
+
     def parseInstr(self):
         instr = self.__getCurrInstr()
 
-        # python, add switch statements *please*
+        match instr.opcode:
-        if instr.opcode == Opcodes.MOVE: # move is a fake ABC instr, C is ignored
+            case Opcodes.MOVE: # move is a fake ABC instr, C is ignored
-            # move registers
+                # move registers
-            self.__setReg(instr.A, self.__getReg(instr.B))
+                self.__setReg(instr.A, self.__getReg(instr.B))
-        elif instr.opcode == Opcodes.LOADK:
+            case Opcodes.LOADK:
-            self.__setReg(instr.A, self.chunk.getConstant(instr.B).toCode())
+                self.__setReg(instr.A, self.chunk.getConstant(instr.B).toCode())
-        elif instr.opcode == Opcodes.LOADBOOL:
+            case Opcodes.LOADBOOL:
-            if instr.B == 0:
+                if instr.B == 0:
-                self.__setReg(instr.A, "false")
+                    self.__setReg(instr.A, "false")
-            else:
+                else:
-                self.__setReg(instr.A, "true")
+                    self.__setReg(instr.A, "true")
-        elif instr.opcode == Opcodes.GETGLOBAL:
+            case Opcodes.GETGLOBAL:
-            self.__setReg(instr.A, self.chunk.getConstant(instr.B).data)
+                self.__setReg(instr.A, self.chunk.getConstant(instr.B).data)
-        elif instr.opcode == Opcodes.GETTABLE:
+            case Opcodes.GETTABLE:
-            self.__setReg(instr.A, self.__getReg(instr.B) + "[" + self.__readRK(instr.C) + "]")
+                self.__setReg(instr.A, self.__getReg(instr.B) + "[" + self.__readRK(instr.C) + "]")
-        elif instr.opcode == Opcodes.SETGLOBAL:
+            case Opcodes.SETGLOBAL:
-            self.__addExpr(self.chunk.getConstant(instr.B).data + " = " + self.__getReg(instr.A))
+                self.__addExpr(self.chunk.getConstant(instr.B).data + " = " + self.__getReg(instr.A))
-            self.__endStatement()
+                self.__endStatement()
-        elif instr.opcode == Opcodes.SETTABLE:
+            case Opcodes.SETTABLE:
-            self.__addExpr(self.__getReg(instr.A) + "[" + self.__readRK(instr.B) + "] = " + self.__readRK(instr.C))
+                self.__addExpr(self.__getReg(instr.A) + "[" + self.__readRK(instr.B) + "] = " + self.__readRK(instr.C))
-            self.__endStatement()
+                self.__endStatement()
-        elif instr.opcode == Opcodes.ADD:
+            case Opcodes.NEWTABLE:
-            self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " + ")
+                self.__parseNewTable(instr.A)
-        elif instr.opcode == Opcodes.SUB:
+            case Opcodes.ADD:
-            self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " - ")
+                self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " + ")
-        elif instr.opcode == Opcodes.MUL:
+            case Opcodes.SUB:
-            self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " * ")
+                self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " - ")
-        elif instr.opcode == Opcodes.DIV:
+            case Opcodes.MUL:
-            self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " / ")
+                self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " * ")
-        elif instr.opcode == Opcodes.MOD:
+            case Opcodes.DIV:
-            self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " % ")
+                self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " / ")
-        elif instr.opcode == Opcodes.POW:
+            case Opcodes.MOD:
-            self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " ^ ")
+                self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " % ")
-        elif instr.opcode == Opcodes.UNM:
+            case Opcodes.POW:
-            self.__setReg(instr.A, "-" + self.__getReg(instr.B))
+                self.__emitOperand(instr.A, self.__readRK(instr.B), self.__readRK(instr.C), " ^ ")
-        elif instr.opcode == Opcodes.NOT:
+            case Opcodes.UNM:
-            self.__setReg(instr.A, "not " + self.__getReg(instr.B))
+                self.__setReg(instr.A, "-" + self.__getReg(instr.B))
-        elif instr.opcode == Opcodes.LEN:
+            case Opcodes.NOT:
-            self.__setReg(instr.A, "#" + self.__getCurrInstr(instr.B))
+                self.__setReg(instr.A, "not " + self.__getReg(instr.B))
-        elif instr.opcode == Opcodes.CONCAT:
+            case Opcodes.LEN:
-            count = instr.C-instr.B+1
+                self.__setReg(instr.A, "#" + self.__getReg(instr.B))
-            concatStr = ""
+            case Opcodes.CONCAT:
+                count = instr.C-instr.B+1
+                concatStr = ""
 
-            # concat all items on stack from RC to RB
+                # concat all items on stack from RC to RB
-            for i in range(count):
+                for i in range(count):
-                concatStr += self.__getReg(instr.B + i) + (" .. " if not i == count - 1 else "")
+                    concatStr += self.__getReg(instr.B + i) + (" .. " if not i == count - 1 else "")
 
-            self.__setReg(instr.A, concatStr)
+                self.__setReg(instr.A, concatStr)
-        elif instr.opcode == Opcodes.JMP:
+            case Opcodes.JMP:
-            pass
+                pass
-        elif instr.opcode == Opcodes.EQ:
+            case Opcodes.EQ:
-            self.__compJmp(" == ")
+                self.__condJmp(" == ")
-        elif instr.opcode == Opcodes.LT:
+            case Opcodes.LT:
-            self.__compJmp(" < ")
+                self.__condJmp(" < ")
-        elif instr.opcode == Opcodes.LE:
+            case Opcodes.LE:
-            self.__compJmp(" <= ")
+                self.__condJmp(" <= ")
-        elif instr.opcode == Opcodes.CALL:
+            case Opcodes.TEST:
-            preStr = ""
+                if instr.C == 0:
-            callStr = ""
+                    self.__condJmp("", False)
-            ident = ""
+                else:
+                    self.__condJmp("not ", False)
+            case Opcodes.CALL:
+                preStr = ""
+                callStr = ""
+                ident = ""
 
-            # parse arguments
+                # parse arguments
-            callStr += self.__getReg(instr.A) + "("
+                callStr += self.__getReg(instr.A) + "("
-            for i in range(instr.A + 1, instr.A + instr.B):
+                for i in range(instr.A + 1, instr.A + instr.B):
-                callStr += self.__getReg(i) + (", " if not i + 1 == instr.A + instr.B else "")
+                    callStr += self.__getReg(i) + (", " if not i + 1 == instr.A + instr.B else "")
-            callStr += ")"
+                callStr += ")"
 
-            # parse return values
+                # parse return values
-            if instr.C > 1:
+                if instr.C > 1:
-                preStr = "local "
+                    preStr = "local "
-                for indx  in range(instr.A, instr.A + instr.C - 1):
+                    for indx  in range(instr.A, instr.A + instr.C - 1):
-                    if indx in self.locals:
+                        if indx in self.locals:
-                        ident = self.locals[indx]
+                            ident = self.locals[indx]
-                    else:
+                        else:
-                        ident = self.__makeLocalIdentifier(indx)
+                            ident = self.__makeLocalIdentifier(indx)
-                    preStr += ident
+                        preStr += ident
 
-                    # normally setReg() does this
+                        # normally setReg() does this
-                    self.top[indx] = ident
+                        self.top[indx] = ident
 
-                    # just so we don't have a trailing ', '
+                        # just so we don't have a trailing ', '
-                    preStr += ", " if not indx == instr.A + instr.C - 2 else ""
+                        preStr += ", " if not indx == instr.A + instr.C - 2 else ""
-                preStr += " = "
+                    preStr += " = "
 
-            self.__addExpr(preStr + callStr)
+                self.__addExpr(preStr + callStr)
-            self.__endStatement()
+                self.__endStatement()
-        elif instr.opcode == Opcodes.RETURN:
+            case Opcodes.RETURN:
-            self.__endStatement()
+                self.__endStatement()
-            pass # no-op for now
+                pass # no-op for now
-        elif instr.opcode == Opcodes.FORLOOP:
+            case Opcodes.FORLOOP:
-            pass # no-op for now
+                pass # no-op for now
-        elif instr.opcode == Opcodes.FORPREP:
+            case Opcodes.FORPREP:
-            self.__addExpr("for %s = %s, %s, %s " % (self.__getLocal(instr.A+3), self.__getReg(instr.A), self.__getReg(instr.A + 1), self.__getReg(instr.A + 2)))
+                self.__addExpr("for %s = %s, %s, %s " % (self.__getLocal(instr.A+3), self.__getReg(instr.A), self.__getReg(instr.A + 1), self.__getReg(instr.A + 2)))
-            self.__startScope("do", self.pc, instr.B)
+                self.__startScope("do", self.pc, instr.B)
-        else:
+            case Opcodes.SETLIST:
-            raise Exception("unsupported instruction: %s" % instr.toString())
+                # LFIELDS_PER_FLUSH (50) is the number of elements that *should* have been set in the list in the *last* SETLIST
+                # eg.
+                # [ 49]      LOADK :  R[49]   K[1]               ; load 0.0 into R[49]
+                # [ 50]      LOADK :  R[50]   K[1]               ; load 0.0 into R[50]
+                # [ 51]    SETLIST :      0     50      1        ; sets list[1..50]
+                # [ 52]      LOADK :   R[1]   K[1]               ; load 0.0 into R[1]
+                # [ 53]    SETLIST :      0      1      2        ; sets list[51..51]
+                numElems = instr.B
+                startAt = ((instr.C - 1) * 50)
+                ident = self.__getLocal(instr.A)
+
+                # set each index (TODO: make tables less verbose)
+                for i in range(numElems):
+                    self.__addExpr("%s[%d] = %s" % (ident, (startAt + i + 1), self.__getReg(instr.A + i + 1)))
+                    self.__endStatement()
+            case Opcodes.CLOSURE:
+                proto = LuaDecomp(self.chunk.protos[instr.B], headChunk=False, scopeOffset=len(self.scope))
+                self.__setReg(instr.A, proto.getPseudoCode())
+            case _:
+                raise Exception("unsupported instruction: %s" % instr.toString())

lundump.py

@@ -1,7 +1,7 @@
 '''
     l(un)dump.py
 
-    A Lua5.1 cross-platform bytecode deserializer. This module pulls int and size_t sizes from the
+    A Lua5.1 cross-platform bytecode deserializer && serializer. This module pulls int and size_t sizes from the
     chunk header, meaning it should be able to deserialize lua bytecode dumps from most platforms,
     regardless of the host machine.
 
@@ -9,11 +9,9 @@
     as well as read the lundump.c source file from the Lua5.1 source.
 '''
 
-from multiprocessing.spawn import get_executable
 import struct
 import array
 from enum import IntEnum, Enum, auto
-from typing_extensions import Self
 
 class InstructionType(Enum):
     ABC = auto(),
@@ -70,6 +68,8 @@ _RKBCInstr = [Opcodes.SETTABLE, Opcodes.ADD, Opcodes.SUB, Opcodes.MUL, Opcodes.D
 _RKCInstr = [Opcodes.GETTABLE, Opcodes.SELF]
 _KBx = [Opcodes.LOADK, Opcodes.GETGLOBAL, Opcodes.SETGLOBAL]
 
+_LUAMAGIC = b'\x1bLua'
+
 # is an 'RK' value a K? (result is true for K, false for R)
 def whichRK(rk: int):
     return (rk & (1 << 8)) > 0
@@ -152,7 +152,7 @@ class Constant:
         self.data = data
 
     def toString(self):
-        return "[" + self.type.name + "] " + str(self.data)
+        return "[%s] %s" % (self.type.name, str(self.data))
 
     # format the constant so that it is parsable by lua
     def toCode(self):
@@ -164,7 +164,7 @@ class Constant:
             else:
                 return "false"
         elif self.type == ConstType.NUMBER:
-            return str(self.data)
+            return "%g" % self.data
         else:
             return "nil"
 
@@ -189,6 +189,7 @@ class Chunk:
         self.maxStack: int = 0
 
         self.upvalues: list[str] = []
+        self.lineNums: list[int] = []
         self.locals: list[Local] = []
 
     def appendInstruction(self, instr: Instruction):
@@ -200,9 +201,15 @@ class Chunk:
     def appendProto(self, proto):
         self.protos.append(proto)
 
+    def appendLine(self, line: int):
+        self.lineNums.append(line)
+
     def appendLocal(self, local: Local):
         self.locals.append(local)
 
+    def appendUpval(self, upval: str):
+        self.upvalues.append(upval)
+
     def findLocal(self, pc: int) -> Local:
         for l in self.locals:
             if l.start <= pc and l.end >= pc:
@@ -298,11 +305,7 @@ class LuaUndump:
         self.rootChunk: Chunk = None
         self.index = 0
 
-    @staticmethod
+    def _loadBlock(self, sz) -> bytearray:
-    def dis_chunk(chunk: Chunk):
-        chunk.print()
-    
-    def loadBlock(self, sz) -> bytearray:
         if self.index + sz > len(self.bytecode):
             raise Exception("Malformed bytecode!")
 
@@ -310,82 +313,71 @@ class LuaUndump:
         self.index = self.index + sz
         return temp
 
-    def get_byte(self) -> int:
+    def _get_byte(self) -> int:
-        return self.loadBlock(1)[0]
+        return self._loadBlock(1)[0]
 
-    def get_int32(self) -> int:
+    def _get_uint32(self) -> int:
-        if (self.big_endian):
+        order = 'big' if self.big_endian else 'little'
-            return int.from_bytes(self.loadBlock(4), byteorder='big', signed=False)
+        return int.from_bytes(self._loadBlock(4), byteorder=order, signed=False)
-        else:
-            return int.from_bytes(self.loadBlock(4), byteorder='little', signed=False)
 
-    def get_int(self) -> int:
+    def _get_uint(self) -> int:
-        if (self.big_endian):
+        order = 'big' if self.big_endian else 'little'
-            return int.from_bytes(self.loadBlock(self.int_size), byteorder='big', signed=False)
+        return int.from_bytes(self._loadBlock(self.int_size), byteorder=order, signed=False)
-        else:
-            return int.from_bytes(self.loadBlock(self.int_size), byteorder='little', signed=False)
 
-    def get_size_t(self) -> int:
+    def _get_size_t(self) -> int:
-        if (self.big_endian):
+        order = 'big' if self.big_endian else 'little'
-            return int.from_bytes(self.loadBlock(self.size_t), byteorder='big', signed=False)
+        return int.from_bytes(self._loadBlock(self.size_t), byteorder=order, signed=False)
-        else:
-            return int.from_bytes(self.loadBlock(self.size_t), byteorder='little', signed=False)
 
-    def get_double(self) -> int:
+    def _get_double(self) -> int:
-        if self.big_endian:
+        order = '>d' if self.big_endian else '<d'
-            return struct.unpack('>d', self.loadBlock(8))[0]
+        return struct.unpack(order, self._loadBlock(self.l_number_size))[0]
-        else:
-            return struct.unpack('<d', self.loadBlock(8))[0]
 
-    def get_string(self, size) -> str:
+    def _get_string(self) -> str:
-        if (size == None):
+        size = self._get_size_t()
-            size = self.get_size_t()
+        if (size == 0):
-            if (size == 0):
+            return ""
-                return ""
 
-        return "".join(chr(x) for x in self.loadBlock(size))
+        # [:-1] to remove the NULL terminator
+        return ("".join(chr(x) for x in self._loadBlock(size)))[:-1]
 
     def decode_chunk(self) -> Chunk:
         chunk = Chunk()
 
-        chunk.name = self.get_string(None)
+        # chunk meta info
-        chunk.frst_line = self.get_int()
+        chunk.name = self._get_string()
-        chunk.last_line = self.get_int()
+        chunk.frst_line = self._get_uint()
-
+        chunk.last_line = self._get_uint()
-        chunk.numUpvals = self.get_byte()
+        chunk.numUpvals = self._get_byte()
-        chunk.numParams = self.get_byte()
+        chunk.numParams = self._get_byte()
-        chunk.isVarg = (self.get_byte() != 0)
+        chunk.isVarg = (self._get_byte() != 0)
-        chunk.maxStack = self.get_byte()
+        chunk.maxStack = self._get_byte()
-
-        if (not chunk.name == ""):
-            chunk.name = chunk.name[1:-1]
 
         # parse instructions
-        num = self.get_int()
+        num = self._get_uint()
         for i in range(num):
-            chunk.appendInstruction(_decode_instr(self.get_int32()))
+            chunk.appendInstruction(_decode_instr(self._get_uint32()))
 
         # get constants
-        num = self.get_int()
+        num = self._get_uint()
         for i in range(num):
             constant: Constant = None
-            type = self.get_byte()
+            type = self._get_byte()
 
-            if type == 0: #nil
+            if type == 0: # nil
                 constant = Constant(ConstType.NIL, None)
             elif type == 1: # bool
-                constant = Constant(ConstType.BOOL, (self.get_byte() != 0))
+                constant = Constant(ConstType.BOOL, (self._get_byte() != 0))
             elif type == 3: # number
-                constant = Constant(ConstType.NUMBER, self.get_double())
+                constant = Constant(ConstType.NUMBER, self._get_double())
             elif type == 4: # string
-                constant = Constant(ConstType.STRING, self.get_string(None)[:-1])
+                constant = Constant(ConstType.STRING, self._get_string())
             else:
                 raise Exception("Unknown Datatype! [%d]" % type)
 
             chunk.appendConstant(constant)
 
         # parse protos
-        num = self.get_int()
+        num = self._get_uint()
         for i in range(num):
             chunk.appendProto(self.decode_chunk())
 
@@ -393,47 +385,47 @@ class LuaUndump:
         # eh, for now just consume the bytes.
 
         # line numbers
-        num = self.get_int()
+        num = self._get_uint()
         for i in range(num):
-            self.get_int()
+            self._get_uint()
 
         # locals
-        num = self.get_int()
+        num = self._get_uint()
         for i in range(num):
-            name = self.get_string(None)[:-1] # local name ([:-1] to remove the NULL terminator)
+            name = self._get_string() # local name
-            start = self.get_int() # local start PC
+            start = self._get_uint() # local start PC
-            end = self.get_int() # local end PC
+            end = self._get_uint() # local end PC
             chunk.appendLocal(Local(name, start, end))
 
         # upvalues
-        num = self.get_int()
+        num = self._get_uint()
         for i in range(num):
-            self.get_string(None) # upvalue name
+            chunk.appendUpval(self._get_string()) # upvalue name
 
         return chunk
 
     def decode_rawbytecode(self, rawbytecode):
         # bytecode sanity checks
-        if not rawbytecode[0:4] == b'\x1bLua':
+        if not rawbytecode[0:4] == _LUAMAGIC:
             raise Exception("Lua Bytecode expected!")
 
         bytecode = array.array('b', rawbytecode)
         return self.decode_bytecode(bytecode)
 
     def decode_bytecode(self, bytecode):
-        self.bytecode   = bytecode
+        self.bytecode = bytecode
 
         # aligns index, skips header
         self.index = 4
-        
+
-        self.vm_version = self.get_byte()
+        self.vm_version = self._get_byte()
-        self.bytecode_format = self.get_byte()
+        self.bytecode_format = self._get_byte()
-        self.big_endian = (self.get_byte() == 0)
+        self.big_endian = (self._get_byte() == 0)
-        self.int_size   = self.get_byte()
+        self.int_size   = self._get_byte()
-        self.size_t     = self.get_byte()
+        self.size_t     = self._get_byte()
-        self.instr_size = self.get_byte() # gets size of instructions
+        self.instr_size = self._get_byte() # gets size of instructions
-        self.l_number_size = self.get_byte() # size of lua_Number
+        self.l_number_size = self._get_byte() # size of lua_Number
-        self.integral_flag = self.get_byte()
+        self.integral_flag = self._get_byte() # is lua_Number defined as an int? false = float/double, true = int/long/short/etc.
 
         self.rootChunk = self.decode_chunk()
         return self.rootChunk
@@ -444,5 +436,122 @@ class LuaUndump:
             return self.decode_rawbytecode(bytecode)
 
     def print_dissassembly(self):
-        LuaUndump.dis_chunk(self.rootChunk)
+        self.rootChunk.print()
 
+class LuaDump:
+    def __init__(self, rootChunk: Chunk):
+        self.rootChunk = rootChunk
+        self.bytecode = bytearray()
+
+        # header info
+        self.vm_version = 0x51
+        self.bytecode_format = 0x00
+        self.big_endian = False
+
+        # data sizes
+        self.int_size = 4
+        self.size_t = 8
+        self.instr_size = 4
+        self.l_number_size = 8
+        self.integral_flag = False # lua_Number is a double
+
+    def _writeBlock(self, data: bytes):
+        self.bytecode += bytearray(data)
+
+    def _set_byte(self, b: int):
+        self.bytecode.append(b)
+
+    def _set_uint32(self, i: int):
+        order = 'big' if self.big_endian else 'little'
+        self._writeBlock(i.to_bytes(4, order, signed=False))
+
+    def _set_uint(self, i: int):
+        order = 'big' if self.big_endian else 'little'
+        self._writeBlock(i.to_bytes(self.int_size, order, signed=False))
+
+    def _set_size_t(self, i: int):
+        order = 'big' if self.big_endian else 'little'
+        self._writeBlock(i.to_bytes(self.size_t, order, signed=False))
+
+    def _set_double(self, f: float):
+        order = '>d' if self.big_endian else '<d'
+        self._writeBlock(struct.pack(order, f))
+
+    def _set_string(self, string: str):
+        self._set_size_t(len(string)+1)
+        self._writeBlock(string.encode('utf-8'))
+        self._set_byte(0x00) # write null terminator
+
+    def _dumpChunk(self, chunk: Chunk):
+        # write meta info
+        self._set_string(chunk.name)
+        self._set_uint(chunk.frst_line)
+        self._set_uint(chunk.last_line)
+        self._set_byte(chunk.numUpvals)
+        self._set_byte(chunk.numParams)
+        self._set_byte(1 if chunk.isVarg else 1)
+        self._set_byte(chunk.maxStack)
+
+        # write instructions
+        self._set_uint(len(chunk.instructions))
+        for l in chunk.instructions:
+            self._set_uint32(_encode_instr(l))
+
+        # write constants
+        self._set_uint(len(chunk.constants))
+        for constant in chunk.constants:
+            # write constant data
+            if constant.type == ConstType.NIL:
+                self._set_byte(0)
+            elif constant.type == ConstType.BOOL:
+                self._set_byte(1)
+                self._set_byte(1 if constant.data else 0)
+            elif constant.type == ConstType.NUMBER: # number
+                self._set_byte(3)
+                self._set_double(constant.data)
+            elif constant.type == ConstType.STRING: # string
+                self._set_byte(4)
+                self._set_string(constant.data)
+            else:
+                raise Exception("Unknown Datatype! [%s]" % str(constant.type))
+
+        # write child protos
+        self._set_uint(len(chunk.protos))
+        for p in chunk.protos:
+            self._dumpChunk(p)
+
+        # write line numbers
+        self._set_uint(len(chunk.lineNums))
+        for l in chunk.lineNums:
+            self._set_uint(l)
+
+        # write locals
+        self._set_uint(len(chunk.locals))
+        for l in chunk.locals:
+            self._set_string(l.name)
+            self._set_uint(l.start)
+            self._set_uint(l.end)
+
+        # write upvals
+        self._set_uint(len(chunk.upvalues))
+        for u in chunk.upvalues:
+            self._set_string(u)
+
+    def _dumpHeader(self):
+        self._writeBlock(_LUAMAGIC)
+
+        # write header info
+        self._set_byte(self.vm_version)
+        self._set_byte(self.bytecode_format)
+        self._set_byte(0 if self.big_endian else 1)
+        self._set_byte(self.int_size)
+        self._set_byte(self.size_t)
+        self._set_byte(self.instr_size)
+        self._set_byte(self.l_number_size)
+        self._set_byte(self.integral_flag)
+
+    def dump(self) -> bytearray:
+        self._dumpHeader()
+        self._dumpChunk(self.rootChunk)
+
+        return self.bytecode

main.py

@@ -1,3 +1,4 @@
+#!/usr/bin/env python3
 import sys
 import lundump
 import lparser
@@ -7,4 +8,8 @@ print(sys.argv[1])
 chunk = lc.loadFile(sys.argv[1])
 
 lc.print_dissassembly()
-lp = lparser.LuaDecomp(chunk)
+
+lp = lparser.LuaDecomp(chunk)
+
+print("\n==== [[" + str(chunk.name) + "'s pseudo-code]] ====\n")
+print(lp.getPseudoCode())