I am looking for the best scripting language interpreter for cross compiling to an ARM processor. Here are the requirements for "best":
Its small. Ideally, I'd like to be able to decide which parts of the language and "standard" libraries that are supported. (For instance: file system, nah don't want that. Floating point math, nope don't want that either.)
Its easy. Ideally, I'd like some documentation/tutorial/examples on how to do the cross-compile.
The goal: I'm writing a small, simple web server in an embedded ARM device and I'd like to do some string processing easily. The code is currently written in C.
I'd like the server and system-level code to be in C. I'd like to write the web "application" in a scripting language. The language features I'm most interested in are:
built-in string support
built-in regex support
built-in map support (i.e key-value pairs object)
I'd like the "best" to come from the following list: Perl, Python, Ruby, Lua. But I would be open to other language suggestions.
I would consider Lua.
Lua is distributed in a small package and builds out-of-the-box in all
platforms that have an ANSI/ISO C compiler. Lua runs on all flavors of
Unix and Windows, and also on mobile devices (such as handheld
computers and cell phones that use BREW, Symbian, Pocket PC, etc.) and
embedded microprocessors (such as ARM and Rabbit) for applications
like Lego MindStorms.
Pattern matching in Lua
Lua tables should meet your map requirement.
Lua string manipulation
Lua compared to Python
(Note: I really like Python and for general purpose scriping would prefer it to Lua but in terms of portability and performance on embedded processors I'd lean towards Lua).
Related
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) ...
I am wondering what is difference between scripting and non scripting language. For example like LUA and C++. Because in game development I often read that they are hiring programmer who must know scripting language. Thank you!
Some of this is somewhat historical in nature.
Non-scripted languages like C and C++ are compiled into "raw machine code" (RMC).
That RMC is then run directly on the machine. Note that RMC is typically
very specific to the underlying CPU/hardware AND to the supporting Operating
System. So if you want to run a C program on both linux and windows, it has to be
compiled for each (two copies to maintain and distribute).
A scripted language is typically NOT compiled. Instead, the source
code is passed to an interpreter that understands the language. The
interpreter itself is typically written in a language that is
itself compiled to RMC. The interpreter's task is to read the
scripted language, and translate that into operations done by RMC.
The line has blurred in recent years (decades?) with the advent of
systems like Java. With languages like Java, source code is
compiled to an intermediate/portable language, and the Java Virtual
Machine handles the translation of that portable language into
operations for the target CPU/OS.
I have seen a lot of C/C++ Libraries and Gui Toolkits. Among them there are some like GTK+ , Qt , Swing etc. which claim to be platform-independent. While some , like WxWidgets, SWT etc. which claim to be cross-platform. At first I thought it to be just a change in wording, but the terms have been used with such consistency that I have started to wonder. What is the difference?
Cross-platform only implies that you support multiple platforms. It usually means Linux, Mac, and Windows. Platform-independent implies that you support any platform that your language supports- i.e., you depend on no behaviour that is not specified in the language specification. However that's just my personal opinion and most uses just take both of them to mean "multiple platforms", usually "Windows and ...".
For what its worth, this is what Wikipedia has to say on the matter:
In order for software to be considered cross-platform, it must be able to function on more than one computer architecture or operating system.
Software that is platform independent does not rely on any special features of any single platform, or, if it does, handles those special features such that it can deal with multiple platforms
"Platform-independent" would usually be a program written in a high-level language that doesn't need recompiling or adjusting for another platform and can just run "as is" (Java, most Perl scripts, etc.) as long as the particular platform implements the language runtime. This is possible when there are layers below the program that deal with different platforms (the VM or the interpreter).
"Cross-platform" implies that the program can be compiled/adjusted for multiple platforms, but not for any platform. Think of #ifdef's in C and C++ code.
Cross-platform means your program can work on different platforms example Windows, Linux, and Mac.
Platform Independent means your code is Write once Run Anywhere i.e. you don't need to change your code to run on different platforms
All platform independent programs are cross-platform but vice versa not true
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++.
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.