Has Lua a future as a general-purpose scripting language? - scripting

As already discussed in "Lua as a general-purpose scripting language?" Lua currently probably isn't the best scripting language for the desktop environment.
But what do you think about the future? Will Lua get so popular that there will soon be enough libraries to be able to use it like Python, Ruby or something similar?
Or will it simply stay in it's WoW niche and that's it?

I think it has a great future, a lot of projects are starting to adopt it for it's simplicity and usefulness.
Example: Awesome WM (Window Manager)
The project recently released version 3, incorporating a new configuration system completely written in Lua. Allowing you to literally write your configuration file as a program, loops, booleans, data structures.
Personally I love the syntax and the flexibility of such a system, I think it has great potential.
I wouldn't be surprised if it became more popular in the future.
Brian G

I suppose the answer starts with 'It depends how you want to use it...'.
If you're writing the common business app (fetch the data from the database, display the data in a web page or window, save the data to the database), Lua already has what you need.
The Kepler Project contains goodies for web development. Check out their modules to see some of the available libraries - there's network, MVC, DBMS access, XML, zip, WSAPI, docs...
As an example web app, check out Sputnik.
For desktop UI, there's wxLua - Lua hooks for wxWidgets.
ORM is conspicuously missing but that didn't stop people from developing in other languages before ORM was available.
If you're looking for specialized libraries - scientific, multimedia , security - don't count Lua out before you check LuaForge.
When it comes down to it, there's nothing in Lua's design that prevents general purpose use. It just happens to be small, fast, and easy to embed... so people do.

Uh? I would say instead WoW is a niche in the Lua ecosystem... The world of Lua doesn't revolve around WoW, there are lot of applications, some big like Adobe Lightroom (to take a non game), using Lua.
Lua is initially a scripting language, in the initial sense, ie. made to be embedded in an application to script it. But it is also designed as an extensible language, so we will see progressively more and more bindings of various libraries for various purposes.
But you will never get an official big distribution with batteries included, like Python or Perl, because it is just not the philosophy of the authors.
Which doesn't prevent other people to make distributions including lot of features out of the box (for Windows, particularly, where it is difficult to build the softwares).
Lot of people already use it for general system-level scripting, desktop applications, and such anyway.

There are more and more libraries for Lua.
If you are a Windows user, have look at Lua for Windows. It comes with "batteries included" (wxLua, LuaCURL, LuaUnit, getopt, LuaXML, LPeg...).
Very usefull!

It's 2017, 9 years after this question was first asked, and lua is now being heavily used in the field of machine learning due to the Torch library.

I really like it as an embedded language. It's small, very easy to use and embed and mostly does what I need right out of the box. It's also similar enough to most languages that it has never really been an issue for me. I also like how easy it is to redefine and add base functions and keywords to the language to suit whatever needs my application has.
I have used it in the WoW area but I've also found it useful as a generic scripting language for a number of different applications I've worked on, including as a type of database trigger. I like Ruby and Python and other more full-featured scripting languages but they're not nearly as convenient for embedding in small applications to give users more options for customizing their environments.

being comfortable as a shell language has nothing to do with being a great general purpose language.
i, for one, don't use it embedded in other applications; i write my applications in Lua, and anything 'extra' is a special-purpose library, either in Lua or in C.
Also, being 'popular' isn't so important. in the Lua-users list periodically someone appears that says "Lua won't be popular unless it does X!", and the usual answer is either: "great!, write it!", or "already discussed and rejected".

I think the great feature of Lua is, that it is very easily extensible. It is very easy to add the Lua interpreter to a program of your own (e.g. one written in C, C++ or Obj-C) and with just a few lines of code, you can give Lua access to any system resource you can think of. E.g. Lua offers no function to do xxx. Write one and make it available to Lua. But it's also possible the other way round. Write your own Lua extension in a language of your choice (one that is compilable), compile it into a native library, load the library within Lua and you can use the function.
That said, Lua might not be the best choice as a standalone crossplatform language. But Lua is a great language to add scripting support to your application in a crossplatform manner (if your app is crossplatform, the better!). I think Lua will have a future and I think you can expect that this language will constantly gain popularity in the long run.

Warhammer Online, and World of Warcraft use it for their addon language I believe.
I think it's hot! I'm just no good at it!

Well, greetings from 2022.
It is already a general purpose language. Today you can even serve pages using OpenResty, extend games, read databases or create scripts as shellscript replacements.
There are a plenty of libraries "modules" for Lua, many ways to achieve what you are wanting and Lua 5.4 is even faster.
The "extendable and extensive" nature of Lua, accostumed people to think it should only be used as plugin or extension. In Linux, by example, you can shebang a file with lua-any, make it executable and run like any system script. Or you can make a folder app like Python or virtualenv using Lupe. Lua 5.3 also gained impressive performance improvements.
Also there are many good tools like IUP to create native windows in Lua for Mac, BSD, Linux and Windows and side environments like Terra that lets you use Lua with its counterpart Terra and write compiled programs. Lua now, is more than a extension language, it has its own universe.

Related

How to develop many-language / multi-platform lib?

Background: I want to develop a component therefore building a class library.
This component should be usable with many higher-order languages such as C, C#, C++, VB, Java, Haskell, Ruby, Erlang, ...
I do not want to exclude any users which are not using my development language.
Are there principles or tools which supports my project?
I searched a little bit and found Haxle for compiling into different languages, but it supports very few of them.
I would even develop parallel in all n languages to be supported, but if I want to change or fix something I have to maintain all other n-1 and the code is possibly distributed...
This is not what I know about clean code design and maintainability. So how to manage edits on code for the different languages?
What is the proper way to solve this? I am surely not the first one which want to build a library for multiple languages.
I want to develop this library (in this case for complexity reduction) in one target language but this time for multiple platforms (Unix, Win, Mac ...).
How to manage this? In fact there will be appreciated about 90% of code which is platform independent and 10% which differs for every OS.
What is the best way to control the changes in the platform dependent code? (The independent is easy ...)
What if I change so things in the part which uses Unix dependent code, then I have to trail all other platform and the code is possibly distributed.
I think #IFDEF is no option ...
Are there any experiences or hints?
I would be delighted if there are existing solutions to these problems, which are quite similar.
What you want is only possible if you provide interfaces for every language you want to support. Some kind of wrapper which transforms between the client language and ypu library.
This is possible but not practical in most cases for standalone libraries.
Take a look at webservices or or message orientad middleware. In this case your application will be provided within a special container which itself provides interface mechanism e.g.
SOAP, XML-RPC to call your application.
For 1), I would use an interface that all these languages can use. A common approach is something based on networking/TCP, like protobuffer, REST, SOAP. Many languages support these in their standard libraries, and interfaces designed with that are normally language agnostic.
There are basically two options - you could develop a network server or you could develop a JVM-based library which could be shared between some of the JVM languages like JRuby or Jython.
Update from #millimoose: you could also develop your library in C and create bindings for all other languages.
For multi-language:
I thought about TCP/middleware/webservices/REST/ which seems to be the recommended proceeding.
But I think it's all to much at runtime for only using a library.
Also the functionality is a little bit time-critical and so direct procedure calls are more fitting (instead of networking even on localhost). And the library user hasn't to construct an access component only to use the library functions.
So I think the way to go seems to be developing the library in a core language which is widely supported (C/C++, ...) and provide wrapper interfaces for the different target languages.
For multi-platform (mono-language):
No real answer has been provided also not in my mind.
Of course I could simply use Java (what I am familiar with) but what about other languages?
I am surely not the first one having this/these problem(s) ...

Sharing logic across different platforms

We have a business logic that works with the file systems on OS that we want to implement on both Linux and Windows platforms. The language we have selected is Python for Linux and C# for Windows. GUI is not a priority for now. We were looking for ways to abstract the business logic in a way that we dont have to repeat the business logic (ofcourse I understand since it is related to file system, some code will differ from platform to platform).
Any ideas on how to implement it? Is C/C++ the only option. We dont want to use Java.
Thanks,
Pranz
yea, pick a common language for the logic first. Punting down in to C/C++ pretty much eliminates any of the real values to development that the Python and C# languages provide. Done write, MOST of your logic will be "Business Logic" with the rest glue to external services (i.e. databases, etc.).
So, you should pick a portable environment from the get go. Dropping down to C/C++ and linking it in is a viable alternative, but most likely not worth the time.
Mono is an option you'll probably want to look into.
Quote from the site for easy explanation:
Mono is a software platform designed to allow developers to easily create cross platform applications. Sponsored by Novell, Mono is an open source implementation of Microsoft's .NET Framework based on the ECMA standards for C# and the Common Language Runtime. A growing family of solutions and an active and enthusiastic contributing community is helping position Mono to become the leading choice for development of Linux applications.
Either use Mono or Python.
Mono allows you to run C# .NET code on both platforms. Python can be executed on both platforms already.
Qt has cross-platform libraries for all sorts of things, including UI and file system. It does, however, use C++.

What language is used when developing apps for multiple platforms?

I just caught one of Google's commercials for Chrome where at the end they mention that it runs on Linux, Mac, and PC. So I started wondering how they are able to develop a program that can run on multiple platforms like that? I have experience with Java, and .Net but only on a windows machine. Java is by design portable, but I wouldn't think Google is using Java for something like Chrome where performance is such a concern.
I understand that each version is going to have some platform specific code, such as for the UI. But there must also be some central code that is reused across each platform. What language is this written in?
Here is an entire article about the development of Chrome. It's mostly written in C++.
Chrome is written in C++, so they will have a significant amount of platform-specific code for each OS. They most likely maintain a separate branch for each OS.
Any reasonably standardized and popular language will do, because the goal is to compile it on all platforms, not create one binary that will work on Windows, MacOSX, Linux, and z/OS. C and C++ are popular choices, because they'll work readily with pretty much anything. Java is a good choice, because it runs on pretty much everything. For applications with low performance requirements, Perl and Python are good.
The important point is to separate out what is platform-dependent from what isn't, since (except in the case of Java or scripting languages) it will probably be necessary to rewrite platform-specific stuff for each platform, and not necessarily in the same language. MacOSX is best programmed in Objective-C, and that's true for no other popular platform.
The programs are supposed to be portable in source level, not binary level. So you only need to compile it for different platforms, not necessary to make one universal binary. In fact, most languages are supported in all modern platforms including UNIX/Windows/Mac, so you can choose from almost all modern lanagues, which C/C++ is prefered by many people. BTW, C++ is the language of Chrome.
Scripting languages like Python/Perl are also good choices. One more thing, Java can be faster than you think - see Eclipse. Even without JNI Technology, Java is still good enough for most applications like JDownloader.
Google had to build different distributions for each OS (ie compiled for each platform as Francis's answer explains) - in fact the Mac OS version only recently became available - the Windows version has been around much longer.
Google Apps are 'thin applications' - the grunt-work is done on their servers.
The Apps are portable in the sense that the front-end is put together using HTML, CSS and Javascript - which are standard (in theory at least) across all browsers.
Google put a lot of effort into building Chrome's Javascript engine to be performant - to ensure any client-side logic is run quickly.

Can statically compiled languages replace scripting language?

Assuming you can get a dynamic interpreter; can statically compiled languages replace scripting language? I never quite understood why anyone would use a scripting language? I am talking about on PC, not a limited system which needs a simplistic interpreter. I seen some python install scripts and seen similar python and C# solutions to a problem. So why use a scripting language?
NOTE: There are things that bother me about C#, i am not asking why not use C# instead. I am asking why use a scripting language? I find static compiled languages much easier to debug and often easier to code in.
There is very little distinction these days between compiling and interpreting. Look at how an interpreted language is executed - the first step is to convert the script into some kind of internal executable form, like byte code that can be executed by a simpler instruction set. This is essentially compilation to a virtual machine format. This is exactly what modern compiled languages do. And when compiled languages are deployed in server-side web apps, they even recompile from the source on the fly. So there's practically no difference in terms of the compile/execute technique.
The only difference is in the details of the instruction set, specifically in the type system. Scripting languages are usually (but not always) dynamically typed. But many large applications are also written in dynamically typed languages too. So again, there is no clear distinction here.
Personally I think static typing, far from being "extra unnecessary effort" (as it is often described) is actually a huge productivity booster, making it much easier to write short snippets correctly on the first attempt, thanks to intellisense/autocompletion. To underline this, look at how Microsoft has improved the jQuery library simply by adding static type information to it (in specially formatted comments) so we can have intellisense in the IDE.
And meanwhile, static languages (including C# and Java) are bringing in more dynamic typing features.
So I see these categories as eventually merging and the distinction being meaningless.
Wikipedia says that a Scripting Language is a language that controls other software. You can do that with C#, but true scripting languages like Powershell are designed specifically for this.
I tend to think of a scripting language in more "interactive" terms than C#. With a scripting language, you can write a line or two of code, execute it and see the results immediately. That's not so easy in C#, where you have to put your code in a Console Application, or fire it off from a unit test, or type it into the Immediate window where you don't have intellisense.
That rapid cycle of write, execute allows rapid prototyping of complete "scripts" in a scripting language, because it gives you immediate feedback on each line of code.
This kind of question often starts flame wars as people are passionate about their respective camps.
In the computer olden days, Unix command line tools and console shells provided a rich scripting environment where all sorts of processing could be done. You didn't need to be an expert programmer in any specific language and could string (pun intended) various programs (other people wrote) together using the pipe structure to massage your data which was mostly text not binary related. It is quick and easy to make changes to your batch command file. You don't have a source file that has to be edited, compiled linked with external static or shared libries/DLLS in the case of Windows.
One thing scripting does not have normally have is speed. You don't write device drives and live internet trading AI systems in scripting. But if you run a script once a day on some data received via e-mail or ftp you don't normally care how long it takes as it can run it background anyway.
Rewind back to the present and the waters become muddy. Some scripting enviroments offer a kind of speed up facility where they will read you script and almost compile and link in modules the same a normal C++ or VB program might use for speed puposes. But this very iffy and can't be relied on.
So how do you choose which route to go. Start doing tasks using scripting. If it runs too slow or you are having to do stuff every 5 minutes then parts of your script might benifit from a section written in a traditional language or the whole thing could be written in a language.
Like anything dabble and learn
Each is used for different purposes. Programs written in scripting languages are often not self-contained; they often function as "glue code" or (as Robert Harvey mentions) to automate a task. You often find scripting language interpreters embedded within an application (cf Python in Blender; Guile, Perl and Python in GIMP; JS in umpteen different browsers; Lua in countless games). Compiled languages, on the other hand, are used to produce self-contained applications. Scripts are mostly cross-platform; compiled applications usually aren't.
Note that a scripting language doesn't necessarily use an interactive interpreter (e.g. Perl), and an interpreted language isn't necessarily use for scripts (e.g. games made using PyGame). Note also that there's nothing about the languages themselves that make them interpreted or compiled. You could have a C# interpreter or a Ruby compiler. There have been a number of Lisp systems that offered both interpreters and compilers.
I would call my shell (bash) a scripting language, and I don't see a replacement comming, which is compiled.
I like to use scala, which is a statically typed language which comes with an interpreter-like REPL-interface, and due to type interference looks pretty much like a scripting language; have a look here: http://www.simplyscala.com/ .
But it isn't meant to be the glue between other programs as the shell is, so for small jobs, which are easily verified by hand and eye, which are just a few lines of code, I prefer to use the shell. And jumping from directory to directory is comfortable in a shell, where the prompt shows where I am.
Before we begin, I don't think that I've ever met a static language user who "got" scripting language without trying them, including myself. It is a different experience.
So no. Basically, you can add features to static languages which makes them superficially seem like scripting languages (like simple type inference), but its not the same:
Many scripting language users hate static languages. They feel constrained. Scripting languages are typically very good at not getting in the users way, which is sacrificed in static languages for speed/correctness.
Duck typing will not appear in static languages.
Scripting language users don't like type annotations. Its not really possible to provide a type-inference system for scripting languages, and the simple type inference appearing in some languages now only works for static types.
Techniques like monkey patching (which to my mind is a very bad idea) is pervasive in Ruby, and allows for very powerful techniques, which won't become available soon in static languages either.
Which isn't to say that a yet-to-be-designed language can't handle scripting language features in a relatively static way, but it would be difficult for it to become popular relative to the entrenched Python/PHP/Perl/Ruby/Javascript set. Factor is the closest thing, AFAICT.
What will happen is that scripting language implementations will get faster by using JITs.
Can a screw driver replace a hammer ? No, because you just don't use them for the same purpose. And if both exist, and if such a lot of people use either one or the other, there must be a reason...
Same anwser for :
class inheritance vs prototype;
imperative vs oo;
static vs dynamic typing;
strongly vs weakly typed;
manual memory management vs GC;
C# vs Java;
blue vs red;
man vs woman;
batman vs superman (but I do think superman would win... wait, there is kryptonite... oh man, I don't know...)
etc...
Because it is shorter to write since it is a higher level language, and it doesn't need the compilation cycle which also makes thing shorter.
I am asking why use a scripting
language? I find static compiled
languages much easier to debug and
often easier to code in.
Because I find loosely-typed dynamic languages without an explicit compile-run cycle much easier to debug and generally easier to code in.

Most appropriate platform independent development language

A project is looming whereby some code that I will be writing may be deployed on any hardware that potential clients happen to have. Its a business application that will be running 24/7 so I envisage that most of the host machines will be server type boxes but smaller clients might, for example, just have a simple PC.
A few more details about the code I will be writing:
There will be no GUI.
It will need to communicate with another bespoke 'black box' device over an Ethernet network.
It will need to communicate with a MySQL database somewhere on the network.
I don't have any performance concerns as a) the number of communications with the black box will be small, around 1 per second, and the amount of data exchanged will be tiny (around 1K each time), b) the number of read/writes with the database will be small, around 5 per minute, and again the amount of data exchanged will be tiny and c) the processing that needs to be performed is fairly simplistic.
Nothing I'm doing is very 'close to the metal' so I don't want to use languages that are too low level. Ease of development and ease of deployment are my main priorities.
I'm not expecting there to be a perfect solution so I can live with things like, for example, having to have slightly different configuration files for Windows machines than for Linux boxes etc. I would like to avoid having to compile the software for each host machine if possible though.
I would value your thoughts as to which development language you think is most suitable.
Cheers,
Jim
I'd go with a decent scripting language such as Python, Perl or Ruby personally. All of those have decent library support, can communicate easily with both local and remote MySQL databases and are pretty platform independent.
The first thing we need to know is what language skills you already have? This is likely to be a fairly big determiner of what choice you would ideally make.
If I was doing this I'd suggest Java for a couple of reasons:
It will run almost anywhere and meet the requirements you've outlined.
Its not an esoteric language so there will be plenty of developers.
I already know how to program in it!
Probably the most extensive library ecosystem of any of the development platforms.
Also note that you could write it in another language on the JVM if your more comfortable with Ruby or Python.
Sounds like Perl or Python would fit the bill perfectly. Which one you choose would depend on the expertise of the people building and supporting the system.
On the subject of scripting languages versus Java, I have been disappointed with developing command line tools using Java. You can't directly execute them, you have to (1) compile them and (2) write a shell script to execute the jar file, this script may differ between platforms. I recommend Python because it runs anywhere and it's got a great SQL library, mysql-python. The library is ready to use on Windows and Linux. Python also has a lot less boilerplate, you'll write fewer lines of code to do the same thing.
EDIT: when I talked about JARs being executable or not, I was talking about whether they are directly executable be the OS. You can, of course, double click on them to run them if your file manager is set up to do so. But when you're in a terminal window and you want to run a java program, you have to "java -jar myapp.jar" instead of the usual "./myapp.jar". In Python one just runs "./myapp.py" and doesn't have to worry about compiling or class paths.
If all platforms are standard PCs (or at least run Linux), then Python should be considered. You can compile it yourself if no package exists for your version. Also, you can strip the standard library easily from things that aren't available and which you don't need (sound support, for example).
Python doesn't need lots of resources, it's easy to learn and read.
If you know Perl, you can try that. If you don't use Perl on a daily basis, then don't. The Perl syntax is hard to remember and after a week, you'll wonder what the code did, even if you wrote it yourself.
Perl may be of help to you as it is available for many platforms and you can get almost any functionality by simply installing modules from CPAN.
Python or Java. They both are easy to deploy on both the server environments and the desktop environments you mention - i.e., Linux/Solaris and Windows.
Perl is also a nice choice, but it depends on how well you know Perl, how well other people that will maintain your code know Perl, and number of desktop users that are savvy enough to handle an install of the Windows Perl version(s).
As Java supports Python via Jython, I'd go with a JVM requirement myself, but I'd personally go with a Java application all the way for such a system you describe.
I would say use C or C++. They are platform independant, though you will have to compile for each platform.
Or use Java. That runs in a Virtual Machine so is truely cross platform and not a slow level as C.