How can I build and compile my own Lua files on Windows? And make them executable.
I am reading Beginning Lua programming, and I have Windows 7 and MacOS Lion both installed. I am having the hard time to follow the instructions. They do not work for me.
On MacOS I open the terminal and put these in:
export LUA_DIR=/usr/local/lib/lua/5.1
mkdir -p /usr/local/lib/lua/5.1 (it tells me, mkdir: illegal option) and I can not follow from here
SET LUA_DIR=”c:\program files\lua\5.1”
As for Windows I do this according to the book.
This what I see in my shell c:\Users\bd>
mkdir "c:\program files\utility" and it tells me access is denied
I have tried to right click on this folder and check off read only, but it does not work.
Any clues would be appreciated, this part has been really confusing for me.
To package your Lua files into an executable on Windows you have several options. There is srlua, there is wxLuaFreeze from wxLua (available as a binary for Windows), and there are more options in this SO answer.
Essentially, the main two options are: (1) append your Lua code to a precompiled exe file, such that it will be loaded and executed when that exe file is run, and (2) convert your Lua code into real executable by compiling it to bytecode, then to C, and then to your target platform.
As to your MacOS issue, mkdir -p means that mkdir is asked to create intermediate directories (for example, you asked to create /a/b/c, it will also create /a/b if those don't exist). As you don't say which version of MacOS you run, it's difficult to provide more detailed answer.
For now the standard distribution of Lua does not compile a script to native executable code; it execute your scripts by first compiling it to bytecode, then by interpreting the bytecode with a reasonnably fast static interpret (this also means that it is easily portable across native or virtual systems, and very resistant to attacks (that could be targetting bugs in the native compiler itself).
Also Lua still does not feature a runtime JIT compiler like Java and .Net: Lua still does not features a VM to produce a safe sandbox.
There exists Lua packages that convert your bytecode (or directly a source script) to a C source that can be used to convert a Lua library into native mode via the same C compiler used to compile the Lua engine itself (this is how the builtin libraries are produced, though they are slightly optimized manually in some time-critical parts).
However it is possible to compile Lua to a javascript source, and run it with fast performance using Javascript, because today's Javascript interprets do have good performance with their implemented VM featuring a JIT compiler for their own bytecodes.
It is also possible by converting it the Lua bytecode to a .Net or Java source that can then be executed directly from Lua (for that you need a version of Lua that has been ported to .Net or Java or Javascript, something that is not so complicate than developing in C/C++ directly a VM with a JIT compiler (a moderately complex part is the bytecode verifier, but the really complex part is the memory manager its garbage collector and its sandbox so that your Lua script will be fully isolated from the Lua engine itself for itw own memory, but the most complex part if the runtime optimizer and collection of profiling statistics: this has been done in the modern VMs for Java, .Net, Javascript, PHP/Zend, Python, Perl...).
I dont know which other language VM would offer the best performance to port Lua and implement on it a compiler to their own bytecode running at near native speed in their VM. But my own small experience with programs (in a much simpler language) self-generating a bytecode that they can run themselves, has always shown me Java winning in performance over .Net and Javascript. This is most probably because Java features an profiling-based dynamic code optimizer
(On the opposite the .Net optimizer runs only once during program installation, using some profiling data collected during the installation of the .Net VM itself, or at first instanciation of the script, without really knowing any profiling data collected during execution of the compiled program itself, and based on some cheked assumptions about the platform capabilities).
I also don't if would be faster in PHP, Python or Perl; the comparison with newer Javascript engines was never attempted though. Porting/compiling a Lua program to Javascript is relatively easy because it implements closures relatively easy for the resolution of linkages. Then the generated Javascript will compile to native code with the excellent Javascript's JIT compilers we have today (and never cease to improve in performance, so much that I've seen various appliactions running now faster in Javascript than before when they were written in C++ or plain C; as well the memory footprint has largely been reduced, we no longer have memory leaks, and even if there's a garbage collector, today's Javascript VM have a very efficient one, which is even better than the GC implemented in the native Lua).
But Lua remains useful as it is easy to secure and sandbox and offers various security benefits (but there are security issues in Lua as well for some kinds of applications, where Javascript offers some solutions, notably for side-channel attacks based on variation of time of execution; but these side-channel attacks are very hard to solve and can affect any system, any program, any programming language, and this starts becoming a critical issue because they are now more esily exploitable; the reason of that comes from hardware optimizations that we depend more and more today when we want to maximize the performances). And with Lua you may be more immune to these problems that a sandboxing sofware environment cannot solve alone.
Probably later we'll see a true VM implementation of Lua with a JIT and self-generating code and the possibility to instanciate new sandboxed VMs to run their self-generated code. It will take more time to generate an EXE file for distribution; notably because it generally requires adding also an installer and a distribution manager.
So for now we could imagine distributing Lua applications compiled to the bytecode of another JIT-capable VM: this generated bytecode would be faster than the Lua bytecode, and would then be extremely complex to reverse-engineer to the semantics of Lua because it would require two separate reverse engineering first from the bytecode of the other VM to the bytecode of Lua, both bytecodes loosing some easiy inferable rules and options tested and foll, and then again to sme Lua source
For the OSX terminal issue:
This command should work
export LUA_DIR=/usr/local/lib/lua/5.1
This command will probably give you permission problems:
mkdir -p /usr/local/lib/lua/5.1
You may try this to solve that. You will be prompted for your password:
sudo mkdir -p /usr/local/lib/lua/5.1
This command has nothing to do with OSX and will not work. This is a windows command:
SET LUA_DIR=”c:\program files\lua\5.1”
You have a permissions problem with Windows- try creating your cmd or PowerShell in Administrator mode. C:\Program Files is a protected directory that a regular user account doesn't have permission to write to.
As for the OS X issue, check out the mkdir OS X manual page to make sure you have the command correct.
So, if I understood your question correctly, you are trying to build Lua on Windows.
This is of course possible, but not easy for beginners. I would highly recommend you to use a binary distribution, which is much easier to install, unless you have special requirements.
Here are several Windows distributions :
Lua Binaries (Lua 5.1 and 5.2)
LuaForWindows (Lua 5.1)
LuaDist (Lua 5.2)
Related
I am writing an F# port of a program I wrote in native code in the past. I used BenchmarkDotNet to measure its performance. I also placed a native EXE in the application's output directory.
I set my native program as the baseline benchmark and saw it was 5x faster than my F# program. Just as I expected!
However, the native program is posted on GitHub and distributed as a Win64 binary only. In case somebody using another OS tries to run it, it will crash.
So, how to specify that this benchmark will only run on 64-bit Windows?
In BenchmarkDotNet, there is a concept of Jobs. Jobs define how the benchmark should be executed.
So, you can express your "x64 only" condition as a job. Note that there are several different 64x jit-compilers depends on runtime (LegacyJIT-x64 and RyuJIT-x64 for the full .NET Framework, RyuJIT-x64 for .NET Core, and Mono JIT compiler). You can request not only a specific platform but also a specific JIT-compiler (it can significantly affect performance), e.g.:
[<RyuJitX64Job>]
member this.MyAwesomeBenchmark () = // ...
In this case, a user will be notified that it's impossible to compile the benchmark for required platform.
Unfortunately, there is no way to require a specific OS for now (there is only one option: current OS). So, in your case, it's probably better to check System.Environment.Is64BitOperatingSystem and System.Environment.OSVersion at the start and don't run benchmarks on invalid operation systems.
Sometimes in s/w companies, customers provide data in multiple formats. There are linkable and executable data that are said to be "Rehosted" and compiled object files that are said to be "Retargeted". I am trying to understand what rehosting and retargeting mean in this area. Is it similar to the Bootstrap theory in computer science? I have the understanding of the following process (if not incorrect):
PROBLEM:
I need to write a compiler for a new language called "MyLang" to run on PowerPC
Solution:
1. I need to write a compiler for a language "MyLang-Mini"; a subset of "MyLang" to run on PowerPC.
2. I need to write a compiler for "MyLang" using "MyLang-Mini" to run on PowerPC.
3. I run the compiler obtained from no. 1 through the compiler obtained from no. 2 to
obtain the compiler for MyLang to run on PowerPC.
IN BESPOKE "T" DIAGRAM (...ISH):
MyLang PowerPC MyLang PowerPC
MyLangMini MyLangMini PowerPC PowerPC(instr.)
PowerPC(instr.)
What I am getting confused about is rehosting and retargeting. How are they coonected to this concept? What am I rehosting and retargeting if I have some binary data such as .exe or .obj? I would appreciate some detailed explanation if possible please!
I know that this will embark onto "CROSS-COMPILERS", but would prefer expert opinions to be sure.
Thanks in advance.
I now know that in s/w engineering:
REHOSTING - If you have a third-party application linkable/executable that requires usage on your host machine, you do rehosting. The target in this case are most often the same (OS platform, processor, etc.). In worst case, there is a virtualisation required. The rehosted application will run as if it was one of the application running in the host machine
RETARGETTING - If you have a third-party source code, you might need to recompile that to match with your target environment. It may also be that you have third-party .o or .obj compiled models and you want to link them with your source code (retargeted) in order to host it on a host machine. Just like REHOSTED application, it will be as if the application was installed on the host machine.
It will be good to know how this is similar to the compiler rehosting and retargeting. Sorry, I am a newbee is this area and will appreciate even a slap on the wrist.
Is there any VM for Erlang that allows you to do compilation on the fly instead of compiling before?
There is a possibility to compile from the shell, thanks Martin.
Now, from the Erlang shell (or some other module!):
1> compile:file("mymod.erl").
{ok,mymod}
2> mymod:myfun().
Hello Joe
Is there any pros or cons with doing this?
Will you still be able to hot swap code?
Is it the regular use-case to handle code?
What benefits does the compiler give you in the end then?
From the Erlang shell, you can compile a module on the fly using c("path/to/module.erl"). You can also access this functionality through the compile module, specifically the compile:file/{1,2} functions.
For example, suppose we have a file mymod.erl:
-module(mymod).
-export([myfun/0]).
myfun() -> io:format("Hello Joe~n").
Now, from the Erlang shell (or some other module!):
1> compile:file("mymod.erl").
{ok,mymod}
2> mymod:myfun().
Hello Joe
See Erldocs on the compile module for more information.
You can do a great deal with the Erlang compiler in runtime. For example, you can dynamically generate code for a module (use erl_syntax!) and then compile it without even writing it to a file using compile:forms/{1,2}.
(Insert standard speech on great power and great responsibility.)
Will you still be able to hot swap code?
Yes.
Is it the regular use-case to handle code?
No. Normally Erlang code is compiled ahead of time into BEAM bytecode. Depending on whether Erlang was started in embedded or interactive mode, the modules are either loaded on startup, or dynamically as they are referenced. If you are building a release, you basically have to compile ahead of time.
What benefits does the compiler give you in the end then?
Well, for one thing, we can build compact releases without unnecessary components like the compiler. Of course, we also get all the traditional benefits of ahead-of-time compilation, particularly that of not having to waste time compiling all the time.
To sum it up, unless you fully understand the implications and have a very good reason not to compile your code ahead of time, please follow the standard practices.
The Erlang VM can only run compiled code! If you want to interpret Erlang code then you need an interpreter. The module erl_eval implements an Erlang interpreter and is part of the standard Erlang/OTP distribution. It is used by the Erlang shell to interpret the expressions entered.
All code handling in the Erlang VM, whether compiling, loading or updating, is done at the module level so it is impossible to compile or load a just one function. The Erlang compiler is written in Erlang and always available and can compile to either a file or a binary which can be immediately loaded into the system. As #MartinTörnwall has pointed out compiling a module from the shell using c(module) is in essence compiling on the fly.
So there would be no problems in automatically compiling code on the fly when it is used, at the module level. It is just that the current system is not designed to work that way and by default when it tries to load a module it only looks for the pre-compiled object file, the .beam file.
Erlang has an interpreter escript. Entire Erlang archive can be written in script. Almost all features are available.
By default, the script will be interpreted. You can force it to be compiled by including the -mode(compile). in the script.
Though it depends on the way you design your application, regular practice is to have .erl files which are compiled and run than having escript files.
So now you have many options.
Compile .erl file to .beam using c(my_module) this auto loads the .beam file. So the existing VM can run it on the fly. On in code you can use compile module functions like file, purge and load to load and run it on the fly.
Compile and keep the .erl files using erlc, erl -make, rebar, etc (Erlang has rich support) and then run it. You can build archives, boot scripts, rel etc to manage running and release of the Erlang software. This usually is the practice for production.
Use escript and run everything in interpreted mode.
Use escript and give -mode(compile) option to tell Erlang VM that at runtime (when starting to run escript) compile the code and run the compiled code (in memory)
Is there any pros or cons with doing this?
Compiled code is faster than interpreted code. I dont see any other right now in Erlang as pretty much everything is supported in both. Erlang even supports combination (Calling compiled code from interpreted code)
Will you still be able to hot swap code?
Yes in all cases. Your code also should be able to handle this.
Is it the regular use-case to handle code?
Option 2 for production. Option for 1 for learning / simple development. Option 3 and 4 in need basis for specific requirements (May be one time running).
What benefits does the compiler give you in the end then?
To make it clear, erlc program provides a common way to run all compilers in the Erlang system and compile module gives an interface to Erlang compilers. Compiler gives intermediate binary .beam file which helps in running Erlang code faster than interpreted counterpart. They also catch syntax errors (compilation errors).
If I compile a regular .lua file with luac, can the result be ran without the Lua library or interpreter installed?
No. You can run it on a version of Lua that was built without the compiler, but you still need the Lua interpreter to execute the code.
Incidentally, the compiled Lua bytecode is also machine-specific; i.e. you can't compile on one architecture and then run that output on another architecture unless you understand the subtleties (endianness, sizes of types, etc.).
If your code doesn't use any dynamic load-based facility (that's loadstring, loadfile, require, etc.) you can strip Lua library to just a VM, because what compiler emits is code to be run on this virtual machine. This can easily cut Lua already small footprint to 1/3 fraction of original.
However, since this is NOT a native binary code for any currently existing architecture, you still CAN'T run it directly without assistance of VM.
I'm trying to learn Lua, but I don't really know which binary to download. There's 2 choices:
Lua Binaries
Lua for Windows
The second option Lua for Windows seems to be the recommended option, but the installer weighs in at 26.6Mb, which is pretty hefty for what is supposed to be a v.lightweight language.
I'm thinking of using Lua as a scripting language for games, and perhaps as a fast development language for file processing like how Python or Ruby does it. So it must be something lightweight, not a 26.6Mb file.
Which is the appropriate one to download and start?
Luaforwindows, no doubt. It's simpler, easier and faster.
The installer comes with lots of stuff (Scite editor & several extra libs if I remember well). But the installer asks you before installing all those extra stuff. Just install the minimum and you will be fine.
Lua for Windows includes a handful of other, useful libraries and tools. The actual Lua executable included is still tiny, in the 1-2MB range as expected.
Having the extras there already will only make things easier, and disk space is cheap: go with Lua for Windows.
You may also want to check ZeroBrane Studio, which is only 4M download on Windows and is based on the same editor as SciTE that comes with Lua for Windows. ZBS also comes with 50+ Lua examples and few simple lessons to get started quickly with Lua programming.
Quoting from here.
Installation
The LuaBinaries files are intended for advanced users and programmers who want to incorporate Lua in their applications or distributions and would like to keep compatibility with LuaBinaries, so they also will be compatible with many other modules available on the Internet.
If what you want is a full Lua installation, please check other projects such as the Lua for Windows and LuaRocks.
Seems quite clear to me that you should download Lua for Windows.