Hopefully this question won't be too convoluted or vague. I know what I want in my head, so fingers crossed I can get this across in text.
I'm looking for a language with a syntax of my own specification, so I assume I will need to create one myself. I've spent the last few days reading about compilers, lexers, parsers, assembly language, virtual machines, etc, and I'm struggling to sort everything out in terms of what I need to accomplish my goals (file attached at the bottom with some specifications). Essentially, I'm deathly confused as to what tools specifically I will need to use to go forward.
A little background: the language made would hopefully be used to implement a multiplayer, text-based MUD server. Therefore, it needs easy inbuilt functionality for creating/maintaining client TCP/IP connections, non-blocking IO, database access via SQL or similar. I'm also interested in security insofar as I don't want code that is written for this language to be able to be stolen and used by the general public without specialist software. This probably means that it should compile to object code
So, what are my best options to create a language that fits these specifications
My conclusions are below. This is just my best educated guess, so please contest me if you think I'm heading in the wrong direction. I'm mostly only including this to see how very confused I am when the experts come to make comments.
For code security, I should want a language that compiles and is run in a virtual machine. If I do this, I'll have a hell of a lot of work to do, won't I? Write a virtual machine, assembler language on the lower-level, and then on the higher-level, code libraries to deal with IO, sockets, etc myself, rather than using existing modules?
I'm just plain confused.
I'm not sure if I'm making sense.
If anyone could settle my brain even a little bit, I'd sincerely appreciate it! Alternatively, if I'm way off course and there's a much easier way to do this, please let me know!
Designing a custom domain-specific programming language is the right approach to a problem. Actually, almost all the problems are better approached with DSLs. Terms you'd probably like to google are: domain specific languages and language-oriented programming.
Some would say that designing and implementing a compiler is a complicated task. It is not true at all. Implementing compilers is a trivial thing. There are hordes of high-quality compilers available, and all you need to do is to define a simple transform from your very own language into another, or into a combination of the other languages. You'd need a parser - it is not a big deal nowdays, with Antlr and tons of homebrew PEG-based parser generators around. You'd need something to define semantics of your language - modern functional programming langauges shines in this area, all you need is something with a support for ADTs and pattern matching. You'd need a target platform. There is a lot of possibilities: JVM and .NET, C, C++, LLVM, Common Lisp, Scheme, Python, and whatever else is made of text strings.
There are ready to use frameworks for building your own languages. Literally, any Common Lisp or Scheme implementation can be used as such a framework. LLVM has all the stuff you'd need too. .NET toolbox is ok - there is a lot of code generation options available. There are specialised frameworks like this one for building languages with complex semantics.
Choose any way you like. It is easy. Much easier than you can imagine.
Writing your own language and tool chain to solve what seems to be a standard problem sounds like the wrong way to go. You'll end up developing yet another language, not writing your MUD.
Many game developers take an approach of using scripting languages to describe their own game world, for example see: http://www.gamasutra.com/view/feature/1570/reflections_on_building_three_.php
Also see: https://stackoverflow.com/questions/356160/which-game-scripting-language-is-better-to-use-lua-or-python for using existing languages (Pythong and LUA) in this case for in-game scripting.
Since you don't know a lot about compilers and creating computer languages: Don't. There are about five people in the world who are good at it.
If you still want to try: Creating a good general purpose language takes at least 3 years. Full time. It's a huge undertaking.
So instead, you should try one of the existing languages which solves almost all of your problems already except maybe the "custom" part. But maybe the language does things better than you ever imagined and you don't need the "custom" part at all.
Here are two options:
Python, a beautiful scripting language. The VM will compile the language into byte code for you, no need to waste time with a compiler. The syntax is very flexible but since there is a good reason for everything in Python, it's not too flexible.
Java. With the new Xtext framework, you can create your own languages in a couple of minutes. That doesn't mean you can create a good language in a few minutes. Just a language.
Python comes with a lot of libraries but if you need anything else, the air gets thin, quickly. On a positive side, you can write a lot of good and solid code in a short time. One line of python is usually equal to 10 lines of Java.
Java doesn't come with a lot of frills but there a literally millions of frameworks out there which do everything you can image ... and a lot of things you can't.
That said: Why limit yourself to one language? With Jython, you can run Python source in the Java VM. So you can write the core (web server, SQL, etc) in Java and the flexible UI parts, the adventures and stuff, in Python.
If you really want to create your own little language, a simpler and often quicker solution is to look at tools like lex and yacc and similar systems (ANTLR is a popular alternative), and then you can generate code either to an existing virtual machine or make a simple one yourself.
Making it all yourself is a great learning-experience, and will help you understand what goes on behind the scenes in other virtual machines.
An excellent source for understanding programming language design and implementation concepts is Structure and Interpretation of Computer Programs from MIT Press. It's a great read for anyone wanting to design and implement a language, or anyone looking to generally become a better programmer.
From what I can understand from this, you want to know how to develop your own programming language.
If so, you can accomplish this by different methods. I just finished up my own a few minutes ago and I used HTML and Javascript (And DOM) to develop my very own. I used a lot of x.split and x.indexOf("code here")!=-1 to do so... I don't have much time to give an example, but if you use W3schools and search "indexOf" and "split" I am sure that you will find what you might need.
I would really like to show you what I did and past the code below, but I can't due to possible theft and claim of my work.
I am pretty much just here to say that you can make your own programming language using HTML and Javascript, so that you and other might not get their hopes too low.
I hope this helps with most things....
I have a task to convert COBOL code to .NET. Are there any converters available? I am trying to understand COBOL code in high level. I have a trouble understanding the COBOL code. Is there any flowchart generators? I appreciate any help.
Thank you..
Migrating software systems from one language or operating environment to another is always a challenge. Here are
a few things to consider:
Legacy code tends to be poorly structured as a result of a
long history of quick fixes and problem work-arounds. This really ups the signal-to-noise ratio
when trying to warp your head around what is really going on.
Converting code leads to further "de-structuring"
to compensate for mis-matches between the source and
target implementation platforms. When you start from a poorly structured base (legacy system),
the end result may be totally un-intelligible.
Documentation of the legacy architecture and/or business processes is generally so far out of
date that it is worse than useless, it may actually be misleading.
Complexity of COBOL code is almost always under estimated.
A number of "features" will be promulgated into the converted system that were originally
built to compensate for things that "couldn't be done" at one time (due to smaller memories,
slower computers etc.). Many of these may now be non-issues and you really don't want them.
There are no obvious or straight forward ways to refactor legacy process driven
systems into an equivalent object oriented system (at least not in a meaningful way).
There have been successful projects that migrated COBOL directly into Java. See naca.
However, the end result is only something its mother (or another COBOL programmer) could love, see this discussion
In general I would be suspicious of any product or tool making claims to convert your COBOL legacy
system into anything but another version of COBOL (e.g. COBOL.net). To this end you still
end up with what is essentially a COBOL system. If this approach is acceptable then you
might want to review this white paper from Micro Focus.
IMHO, your best bet for replacing COBOL is to re-engineer your system. If you ever find
a silver bullet to get from where you are to where you want to be - write a book, become
a consultant and make many millions of dollars.
Sorry to have provided such a negative answer, but if you are working with anything
but a trivial legacy system, the problem is going to be anything but trivial to solve.
Note: Don't bother with flowcharting the existing system. Try to get a handle on process input/output and program to program data transformation and flow. You need to understand the business function here, not a specific implementation of it.
Micro Focus and Fujitsu both have COBOL products that work with .NET. Micro Focus allow you to download a product trial, while the Fujitsu NetCOBOL site has a number of articles and case studies.
Micro Focus
http://www.microfocus.com/products/micro-focus-developer/micro-focus-cobol/windows-and-net/micro-focus-visual-cobol.aspx
Fujitsu
http://www.netcobol.com/products/Fujitsu-NetCOBOL-for-.NET/overview
[Note: I work for Micro Focus]
Hi
Actually, making COBOL applications available on the .NET framework is pretty straightforward (contrary to claim made in one of the earlier responses). Fujitsu and Micro Focus both have COBOL compilers that can create ILASM code for execution in the CLR.
Micro Focus Visual COBOL (http://www.microfocus.com/visualcobol) makes it particularly easy to deploy traditional, procedural COBOL as managed code with full support for COBOL data types, file systems etc. It also includes an updated OO COBOL syntax that takes away a lot of the verbosity & complexity of the syntax to be very easy to write COBOL code based on C# examples. It's unique approach also makes it easy to use all the Visual Studio tools such as IntelliSense.
The original question mentioned "convert" and I would strongly recommend against any approach that requires the source code to be converted to some other language before being used in a .NET environment. The amount of effort and risk involved is highly unlikely to be worth any benefits accrued. On the contrary, keeping the code in COBOL maintains the existing, working code and allows for the option to deploy onto other platforms in the future. For example, how about having a single set of source code and having the option to deploy into .NET as a native language and into a Java environment without changing a line of source code?
I recommend you get a trial copy of Visual COBOL from the link above and see how you can use your existing code in .NET without making any changes.
This is not an easy task. COBOL has fundamental ideas about data types that do not map well with the object-oriented .NET framework (e.g. in COBOL, all data types are represented in terms of fixed-size buffers) and in particular the way groups and arrays work do not map well to .NET classes.
I believe there are COBOL compilers that can actually compile .NET bytecode, but they would have their own runtime libraries to manage all of that. It might be worth looking at one of these compilers and simply leaving the legacy code in COBOL.
Other than that, line-by-line translation is probably not possible. Look at the code at a higher level and translate blocks of code at a time (e.g. at the procedure level or even higher).
There are a lot mechanisms how to convert COBOL to modern scalable environments, such as .NET or Java.
The first is a migration to a new environment with saving the existing COBOL code with some minor modifications (NET Microfocus COBOL);
The second is a migration to a new platform with simulation of COBOL statements and constructions. When there are some additional NET/Java libraries to simulate some specific COBOL logic:
ACCEPT goes to NETLibrary.Accept and so on.
The third approach is the most valuable one, when you migrate to "pure" NET/Java code with all the benefits of the new environment. It can be easily maintained and developed in the future.
However, the unique expertise and toolkits are required for this approach, and there are only a few players on the global market that can help you in this case.
If we are talking about automatic migration, the number of players decreases greatly and, unfortunately for you, you have to pay for the specific technologies and tools (like ours).
However, it is a better idea to invest your money in your future growth in the modern environment, than to spend your money on the "simulation" of old technologies.
Translations is not an easy task. Besides Micro Focus and Fujitsu there is also Raincode that offers a free version of Cobol that nicely integrates with Visual Studio.
Let's say that you have to implement some functionality that is not trivial (it will take at least 1 work week). You have a SDK/API/library that contains (numerous) code samples demonstrating the usage of the part of the SDK for implementing that functionality.
How do you approach learning all the samples, extract the necessary information, techniques, etc. in order to use them to implement the 'real thing'. The key questions are:
Do you use some tool for diagramming of the control flow, the interactions between the functions from the SDK, and the sample itself? Which kind of diagrams do you find useful? (I was thinking that the UML sequence diagram can be quite useful together with the debugger in this case).
How do you keep the relevant and often interrelated information about SDK/API function calls, the general structure and calls order in the sample programs that have to be used as a reference - mind maps, some plain text notes, added comments in the samples code, some refactoring of the sample code to suit your personal coding style in order to make the learning easier?
Personally I use the prototyping approach. Keep development to manageable iterations. In the beginning, those iterations are really small. As part of this, don't be afraid to throw code away and start again (everytime I say that somewhere a project manager has a heart attack).
If your particular task can't easily or reasonably be divided into really small starting tasks then start with some substitute until you get going.
You want to keep it as simple as you can (the proverbial "Hello world") just to familiarize yourself with building, deploying, debugging, what error messages look like, the simple things that can and do go wrong in the beginning, etc.
I don't go as far as using a diagramming tool sorry (I barely see the point in that for my job).
As soon as you start trying things you'll get the hang of it, even if in the beginning you have no idea of what's going on and why what you're doing works (or doesn't).
I usually compile and modify the examples, making them fit something that I need to do myself. I tend to do this while using and annotating the corresponding documents. Being a bit old school, the tool I usually use for diagramming is a pencil, or for the really complex stuff two or more colored pens.
I am by no means a seasoned programmer. In fact, I am learning C++ and I've been studying the language primarily from books. When I try to stray from the books (which happens a lot because I want to start contributing to programs like LibreOffice), for example, I find myself being lost. Furthermore, when I'm using functionality of the library, my implementations are wrong because I don't really understand how the library was created and/or why things need to be done that way. When I look at sample source code, I see how something is done, but I don't understand why it's done that way which leads to poor design of my programs. And as a result, I'm constantly guessing at how to do something and dealing with errors as I encounter them. Very unproductive and frustrating.
Going back to my book comment, two books which I have ready from cover to cover more than once are Ivor Horton's Beginning Visual C++ 2010 and Starting Out with C++: Early Objects (7th Edition). What I really loved about Ivor Horton's book is that it contained thorough explanation of why something needs to be done a certain way. For example, before any Windows programming began, lots of explanation about how Windows works was given first. Understanding how and why things work a certain way really helps in how I develop software.
So to contribute my two pennies towards answering your question. I think the best approach is to pick up well written books and sit down and begin learning about that library, API, SDK, whatever in a structured approach that offers real-world examples along with explanations as to how and why things are implemented as they are.
I don't know if I totally missed your question, but I don't think I did.
Cheers!
This was my first post on this site. Don't rip me too hard. (:
I am trying to build out a useful 3d game engine out of the Ogre3d rendering engine for mocking up some of the ideas i have come up with and have come to a bit of a crossroads. There are a number of scripting languages that are available and i was wondering if there were one or two that were vetted and had a proper following.
LUA and Squirrel seem to be the more vetted, but im open to any and all.
Optimally it would be best if there were a compiled form for the language for distribution and ease of loading.
One interesting option is stackless-python. This was used in the Eve-Online game.
The syntax is a matter of taste, Lua is like Javascript but with curly braces replaced with Pascal-like keywords. It has the nice syntactic feature that semicolons are never required but whitespace is still not significant, so you can even remove all line breaks and have it still work. As someone who started with C I'd say Python is the one with esoteric syntax compared to all the other languages.
LuaJIT is also around 10 times as fast as Python and the Lua interpreter is much much smaller (150kb or around 15k lines of C which you can actually read through and understand). You can let the user script your game without having to embed a massive language. On the other hand if you rip the parser part out of Lua it becomes even smaller.
The Python/C API manual is longer than the whole Lua manual (including the Lua/C API).
Another reason for Lua is the built-in support for coroutines (co-operative multitasking within the one OS thread). It allows one to have like 1000's of seemingly individual scripts running very fast alongside each other. Like one script per monster/weapon or so.
( Why do people write Lua in upper case so much on SO? It's "Lua" (see here). )
One more vote for Lua. Small, fast, easy to integrate, what's important for modern consoles - you can easily control its memory operations.
I'd go with Lua since writing bindings is extremely easy, the license is very friendly (MIT) and existing libraries also tend to be under said license. Scheme is also nice and easy to bind which is why it was chosen for the Gimp image editor for example. But Lua is simply great. World of Warcraft uses it, as a very high profile example. LuaJIT gives you native-compiled performance. It's less than an order of magnitude from pure C.
I wouldn't recommend LUA, it has a peculiar syntax so takes some time to get used to. Depending on who will be doing the scripting, this may not be a problem, but I would try to use something fairly accessible.
I would probably choose python. It normally compiles to bytecode, so you would need to embed the interpreter. However, if you must you can use PyPy to for example translate the code to C, and then compile it.
Embedding the interpreter is no issue. I am more interested in features and performance at this point in time. LUA and Squirrel are both interpreted, which is nice because one of the games i am building out is to include modifiable code, which has an editor in game.
I would love to hear about python, as i have seen its use within the battlefield series i believe.
python is also nice because it has actual OGRE bindings, just in case you need to modify something lower-level on the fly. I don't know of any equivalent bindings for Lua.
Since it's a C++ library, I would suggest either JavaScript or Squirrel, the latter being my personal favorite of the two for being even closer to C++, in particular to how it handles tables/structs and classes. It would be the easiest to get used to for a C++ coder because of all the similarities.
However, if you go with JavaScript and find an HTML5 version of Ogre3D, you should be able to port your game code directly into the web version with minimal (if any) changes necessary.
Both of these are a good choice, and both have their pros and cons, but both would definitely be the easiest to learn since you're likely already working in C++. If you're working with Java, the same may hold true, and if it's Game Maker, you wouldn't need either one unless you're trying to make an executable that people wouldn't need Game Maker itself to run, in which case, good luck finding an extension to run either of these.
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I am part of a high school robotics team, and there is some debate about which language to use to program our robot. We are choosing between C (or maybe C++) and LabVIEW. There are pros for each language.
C(++):
Widely used
Good preparation for the future (most programming positions require text-based programmers.)
We can expand upon our C codebase from last year
Allows us to better understand what our robot is doing.
LabVIEW
Easier to visualize program flow (blocks and wires, instead of lines of code)
Easier to teach (Supposedly...)
"The future of programming is graphical." (Think so?)
Closer to the Robolab background that some new members may have.
Don't need to intimately know what's going on. Simply tell the module to find the red ball, don't need to know how.
This is a very difficult decision for us, and we've been debating for a while. Based on those pros for each language, and on the experience you've got, what do you think the better option is? Keep in mind that we aren't necessarily going for pure efficiency. We also hope to prepare our programmers for a future in programming.
Also:
Do you think that graphical languages such as LabVEIW are the future of programming?
Is a graphical language easier to learn than a textual language? I think that they should be about equally challenging to learn.
Seeing as we are partailly rooted in helping people learn, how much should we rely on prewritten modules, and how much should we try to write on our own? ("Good programmers write good code, great programmers copy great code." But isn't it worth being a good programmer, first?)
Thanks for the advice!
Edit:
I'd like to emphasize this question more:
The team captain thinks that LabVIEW is better for its ease of learning and teaching. Is that true? I think that C could be taught just as easily, and beginner-level tasks would still be around with C. I'd really like to hear your opinions. Is there any reason that typing while{} should be any more difficult than creating a "while box?" Isn't it just as intuitive that program flows line by line, only modified by ifs and loops, as it is intuitive that the program flows through the wire, only modified by ifs and loops!?
Thanks again!
Edit:
I just realized that this falls under the topic of "language debate." I hope it's okay, because it's about what's best for a specific branch of programming, with certain goals. If it's not... I'm sorry...
Before I arrived, our group (PhD scientists, with little programming background) had been trying to implement a LabVIEW application on-and-off for nearly a year. The code was untidy, too complex (front and back-end) and most importantly, did not work. I am a keen programmer but had never used LabVIEW. With a little help from a LabVIEW guru who could help translate the textual progamming paradigms I knew into LabVIEW concepts it was possible to code the app in a week. The point here is that the basic coding concepts still have to be learnt, the language, even one like LabVIEW, is just a different way of expressing them.
LabVIEW is great to use for what it was originally designed for. i.e. to take data from DAQ cards and display it on-screen perhaps with some minor manipulations in-between. However, programming algorithms is no easier and I would even suggest that it is more difficult. For example, in most procedural languages execution order is generally followed line by line, using pseudo mathematical notation (i.e. y = x*x + x + 1) whereas LabVIEW would implement this using a series of VI's which don't necessarily follow from each other (i.e. left-to-right) on the canvas.
Moreover programming as a career is more than knowing the technicalities of coding. Being able to effectively ask for help/search for answers, write readable code and work with legacy code are all key skills which are undeniably more difficult in a graphical language such as LabVIEW.
I believe some aspects of graphical programming may become mainstream - the use of sub-VIs perfectly embodies the 'black-box' principal of programming and is also used in other language abstractions such as Yahoo Pipes and the Apple Automator - and perhaps some future graphical language will revolutionise the way we program but LabVIEW itself is not a massive paradigm shift in language design, we still have while, for, if flow control, typecasting, event driven programming, even objects. If the future really will be written in LabVIEW, C++ programmer won't have much trouble crossing over.
As a postcript I'd say that C/C++ is more suited to robotics since the students will no doubt have to deal with embedded systems and FPGAs at some point. Low level programming knowledge (bits, registers etc.) would be invaluable for this kind of thing.
#mendicant Actually LabVIEW is used a lot in industry, especially for control systems. Granted NASA unlikely use it for on-board satellite systems but then software developement for space-systems is a whole different ball game...
I've encountered a somewhat similar situation in the research group I'm currently working in. It's a biophysics group, and we're using LabVIEW all over the place to control our instruments. That works absolutely great: it's easy to assemble a UI to control all aspects of your instruments, to view its status and to save your data.
And now I have to stop myself from writing a 5 page rant, because for me LabVIEW has been a nightmare. Let me instead try to summarize some pros and cons:
Disclaimer I'm not a LabVIEW expert, I might say things that are biased, out-of-date or just plain wrong :)
LabVIEW pros
Yes, it's easy to learn. Many PhD's in our group seem to have acquired enough skills to hack away within a few weeks, or even less.
Libraries. This is a major point. You'd have to carefully investigate this for your own situation (I don't know what you need, if there are good LabVIEW libraries for it, or if there are alternatives in other languages). In my case, finding, e.g., a good, fast charting library in Python has been a major problem, that has prevented me from rewriting some of our programs in Python.
Your school may already have it installed and running.
LabVIEW cons
It's perhaps too easy to learn. In any case, it seems no one really bothers to learn best practices, so programs quickly become a complete, irreparable mess. Sure, that's also bound to happen with text-based languages if you're not careful, but IMO it's much more difficult to do things right in LabVIEW.
There tend to be major issues in LabVIEW with finding sub-VIs (even up to version 8.2, I think). LabVIEW has its own way of knowing where to find libraries and sub-VIs, which makes it very easy to completely break your software. This makes large projects a pain if you don't have someone around who knows how to handle this.
Getting LabVIEW to work with version control is a pain. Sure, it can be done, but in any case I'd refrain from using the built-in VC. Check out LVDiff for a LabVIEW diff tool, but don't even think about merging.
(The last two points make working in a team on one project difficult. That's probably important in your case)
This is personal, but I find that many algorithms just don't work when programmed visually. It's a mess.
One example is stuff that is strictly sequential; that gets cumbersome pretty quickly.
It's difficult to have an overview of the code.
If you use sub-VI's for small tasks (just like it's a good practice to make functions that perform a small task, and that fit on one screen), you can't just give them names, but you have to draw icons for each of them. That gets very annoying and cumbersome within only a few minutes, so you become very tempted not to put stuff in a sub-VI. It's just too much of a hassle. Btw: making a really good icon can take a professional hours. Go try to make a unique, immediately understandable, recognizable icon for every sub-VI you write :)
You'll have carpal tunnel within a week. Guaranteed.
#Brendan: hear, hear!
Concluding remarks
As for your "should I write my own modules" question: I'm not sure. Depends on your time constraints. Don't spend time on reinventing the wheel if you don't have to. It's too easy to spend days on writing low-level code and then realize you've run out of time. If that means you choose LabVIEW, go for it.
If there'd be easy ways to combine LabVIEW and, e.g., C++, I'd love to hear about it: that may give you the best of both worlds, but I doubt there are.
But make sure you and your team spend time on learning best practices. Looking at each other's code. Learning from each other. Writing usable, understandable code. And having fun!
And please forgive me for sounding edgy and perhaps somewhat pedantic. It's just that LabVIEW has been a real nightmare for me :)
I think the choice of LabVIEW or not comes down to whether you want to learn to program in a commonly used language as a marketable skill, or just want to get stuff done. LabVIEW enables you to Get Stuff Done very quickly and productively. As others have observed, it doesn't magically free you from having to understand what you're doing, and it's quite possible to create an unholy mess if you don't - although anecdotally, the worst examples of bad coding style in LabVIEW are generally perpetrated by people who are experienced in a text language and refuse to adapt to how LabVIEW works because they 'already know how to program, dammit!'
That's not to imply that LabVIEW programming isn't a marketable skill, of course; just that it's not as mass-market as C++.
LabVIEW makes it extremely easy to manage different things going on in parallel, which you may well have in a robot control situation. Race conditions in code that should be sequential shouldn't be a problem either (i.e. if they are, you're doing it wrong): there are simple techniques for making sure that stuff happens in the right order where necessary - chaining subVI's using the error wire or other data, using notifiers or queues, building a state machine structure, even using LabVIEW's sequence structure if necessary. Again, this is simply a case of taking the time to understand the tools available in LabVIEW and how they work. I don't think the gripe about having to make subVI icons is very well directed; you can very quickly create one containing a few words of text, maybe with a background colour, and that will be fine for most purposes.
'Are graphical languages the way of the future' is a red herring based on a false dichotomy. Some things are well suited to graphical languages (parallel code, for instance); other things suit text languages much better. I don't expect LabVIEW and graphical programming to either go away, or take over the world.
Incidentally, I would be very surprised if NASA didn't use LabVIEW in the space program. Someone recently described on the Info-LabVIEW mailing list how they had used LabVIEW to develop and test the closed loop control of flight surfaces actuated by electric motors on the Boeing 787, and gave the impression that LabVIEW was used extensively in the plane's development. It's also used for real-time control in the Large Hadron Collider!
The most active place currently for getting further information and help with LabVIEW, apart from National Instruments' own site and forums, seems to be LAVA.
This doesn't answer you question directly, but you may want to consider a third option of mixing in an interpreted language. Lua, for example, is already used in the robotics field. It's fast, light-weight and can be configured to run with fixed-point numbers instead of floating-point since most microcontrollers don't have an FPU. Forth is another alternative with similar usage.
It should be pretty easy to write a thin interface layer in C and then let the students loose with interpreted scripts. You could even set it up to allow code to be loaded dynamically without recompiling and flashing a chip. This should reduce the iteration cycle and allow students to learn better by seeing results more quickly.
I'm biased against using visual tools like LabVIEW. I always seem to hit something that doesn't or won't work quite like I want it to do. So, I prefer the absolute control you get with textual code.
LabVIEW's other strength (besides libraries) is concurrency. It's a dataflow language, which means that the runtime can handle concurrency for you. So if you're doing something highly concurrent and don't want to have to do traditional synchronization, LabVIEW can help you there.
The future doesn't belong to graphical languages as they stand today. It belongs to whoever can come up with a representation of dataflow (or another concurrency-friendly type of programming) that's as straightforward as the graphical approach is, but is also parsable by the programmer's own tools.
There is a published study of the topic hosted by National Instruments:
A Study of Graphical vs. Textual Programming for Teaching DSP
It specifically looks at LabVIEW versus MATLAB (as opposed to C).
I think that graphical languages wil always be limited in expressivity compared to textual ones. Compare trying to communicate in visual symbols (e.g., REBUS or sign language) to communicating using words.
For simple tasks, using a graphical language is usually easier but for more intricate logic, I find that graphical languages get in the way.
Another debate implied in this argument, though, is declarative programming vs. imperative. Declarative is usually better for anything where you really don't need the fine-grained control over how something is done. You can use C++ in a declarative way but you would need more work up front to make it so, whereas LABView is designed as a declarative language.
A picture is worth a thousand words but if a picture represents a thousand words that you don't need and you can't change that, then in that case a picture is worthless. Whereas, you can create thousands of pictures using words, specifying every detail and even leading the viewer's focus explicitly.
LabVIEW lets you get started quickly, and (as others have already said) has a massive library of code for doing various test, measurement & control related things.
The single biggest downfall of LabVIEW, though, is that you lose all the tools that programmers write for themselves.
Your code is stored as VIs. These are opaque, binary files. This means that your code really isn't yours, it's LabVIEW's. You can't write your own parser, you can't write a code generator, you can't do automated changes via macros or scripts.
This sucks when you have a 5000 VI app that needs some minor tweak applied universally. Your only option is to go through every VI manually, and heaven help you if you miss a change in one VI off in a corner somewhere.
And yes, since it's binary, you can't do diff/merge/patch like you can with textual languages. This does indeed make working with more than one version of the code a horrific nightmare of maintainability.
By all means, use LabVIEW if you're doing something simple, or need to prototype, or don't plan to maintain your code.
If you want to do real, maintainable programming, use a textual language. You might be slower getting started, but you'll be faster in the long run.
(Oh, and if you need DAQ libraries, NI's got C++ and .Net versions of those, too.)
My first post here :) be gentle ...
I come from an embedded background in the automotive industry and now i'm in the defense industry. I can tell you from experience that C/C++ and LabVIEW are really different beasts with different purposes in mind. C/C++ was always used for the embedded work on microcontrollers because it was compact and compilers/tools were easy to come by. LabVIEW on the other hand was used to drive the test system (along with test stand as a sequencer). Most of the test equipment we used were from NI so LabVIEW provided an environment where we had the tools and the drivers required for the job, along with the support we wanted ..
In terms of ease of learning, there are many many resources out there for C/C++ and many websites that lay out design considerations and example algorithms on pretty much anything you're after freely available. For LabVIEW, the user community's probably not as diverse as C/C++, and it takes a little bit more effort to inspect and compare example code (have to have the right version of LabVIEW etc) ... I found LabVIEW pretty easy to pick up and learn, but there a nuisances as some have mentioned here to do with parallelism and various other things that require a bit of experience before you become aware of them.
So the conclusion after all that? I'd say that BOTH languages are worthwhile in learning because they really do represent two different styles of programming and it is certainly worthwhile to be aware and proficient at both.
Oh my God, the answer is so simple. Use LabView.
I have programmed embedded systems for 10 years, and I can say that without at least a couple months of infrastructure (very careful infrastructure!), you will not be as productive as you are on day 1 with LabView.
If you are designing a robot to be sold and used for the military, go ahead and start with C - it's a good call.
Otherwise, use the system that allows you to try out the most variety in the shortest amount of time. That's LabView.
I love LabVIEW. I would highly recommend it especially if the other remembers have used something similar. It takes a while for normal programmers to get used to it, but the result's are much better if you already know how to program.
C/C++ equals manage your own memory. You'll be swimming in memory links and worrying about them. Go with LabVIEW and make sure you read the documentation that comes with LabVIEW and watch out for race conditions.
Learning a language is easy. Learning how to program is not. This doesn't change even if it's a graphical language. The advantage of Graphical languages is that it is easier to visual what the code will do rather than sit there and decipher a bunch of text.
The important thing is not the language but the programming concepts. It shouldn't matter what language you learn to program in, because with a little effort you should be able to program well in any language. Languages come and go.
Disclaimer: I've not witnessed LabVIEW, but I have used a few other graphical languages including WebMethods Flow and Modeller, dynamic simulation languages at university and, er, MIT's Scratch :).
My experience is that graphical languages can do a good job of the 'plumbing' part of programming, but the ones I've used actively get in the way of algorithmics. If your algorithms are very simple, that might be OK.
On the other hand, I don't think C++ is great for your situation either. You'll spend more time tracking down pointer and memory management issues than you do in useful work.
If your robot can be controlled using a scripting language (Python, Ruby, Perl, whatever), then I think that would be a much better choice.
Then there's hybrid options:
If there's no scripting option for your robot, and you have a C++ geek on your team, then consider having that geek write bindings to map your C++ library to a scripting language. This would allow people with other specialities to program the robot more easily. The bindings would make a good gift to the community.
If LabVIEW allows it, use its graphical language to plumb together modules written in a textual language.
I think that graphical languages might be the language of the future..... for all those adhoc MS Access developers out there. There will always be a spot for the purely textual coders.
Personally, I've got to ask what is the real fun of building a robot if it's all done for you? If you just drop a 'find the red ball' module in there and watch it go? What sense of pride will you have for your accomplishment? Personally, I wouldn't have much. Plus, what will it teach you of coding, or of the (very important) aspect of the software/hardware interface that is critical in robotics?
I don't claim to be an expert in the field, but ask yourself one thing: Do you think that NASA used LabVIEW to code the Mars Rovers? Do you think that anyone truly prominent in robotics is using LabView?
Really, if you ask me, the only thing using cookie cutter things like LabVIEW to build this is going to prepare you for is to be some backyard robot builder and nothing more. If you want something that will give you something more like industry experience, build your own 'LabVIEW'-type system. Build your own find-the-ball module, or your own 'follow-the-line' module. It will be far more difficult, but it will also be way more cool too. :D
You're in High School. How much time do you have to work on this program? How many people are in your group? Do they know C++ or LabView already?
From your question, I see that you know C++ and most of the group does not. I also suspect that the group leader is perceptive enough to notice that some members of the team may be intimidated by a text based programming language. This is acceptable, you're in high school, and these people are normies. I feel as though normal high schoolers will be able to understand LabView more intuitively than C++. I'm guessing most high school students, like the population in general, are scared of a command line. For you there is much less of a difference, but for them, it is night and day.
You are correct that the same concepts may be applied to LabView as C++. Each has its strengths and weaknesses. The key is selecting the right tool for the job. LabView was designed for this kind of application. C++ is much more generic and can be applied to many other kinds of problems.
I am going to recommend LabView. Given the right hardware, you can be up and running almost out-of-the-box. Your team can spend more time getting the robot to do what you want, which is what the focus of this activity should be.
Graphical Languages are not the future of programming; they have been one of the choices available, created to solve certain types of problems, for many years. The future of programming is layer upon layer of abstraction away from machine code. In the future, we'll be wondering why we wasted all this time programming "semantics" over and over.
how much should we rely on prewritten modules, and how much should we try to write on our own?
You shouldn't waste time reinventing the wheel. If there are device drivers available in Labview, use them. You can learn a lot by copying code that is similar in function and tailoring it to your needs - you get to see how other people solved similar problems, and have to interpret their solution before you can properly apply it to your problem. If you blindly copy code, chances of getting it to work are slim. You have to be good, even if you copy code.
Best of luck!
I would suggest you use LabVIEW as you can get down to making the robot what you want to do faster and easier. LabVIEW has been designed with this mind. OfCourse C(++) are great languages, but LabVIEW does what it is supposed to do better than anything else.
People can write really good software in LabVIEW as it provides ample scope and support for that.
There is one huge thing I found negative in using LabVIEW for my applications: Organize design complexity. As a physisist I find Labview great for prototyping, instrument control and mathematical analysis. There is no language in which you get faster and better a result then in LabVIEW. I used LabView since 1997. Since 2005 I switched completely to the .NET framework, since it is easier to design and maintain.
In LabVIEW a simple 'if' structure has to be drawn and uses a lot of space on your graphical design. I just found out that many of our commercial applications were hard to maintain. The more complex the application became, the more difficult it was to read.
I now use text laguages and I am much better in maintaining everything. If you would compare C++ to LabVIEW I would use LabVIEW, but compared to C# it does not win
As allways, it depends.
I am using LabVIEW since about 20 years now and did quite a large kind of jobs, from simple DAQ to very complex visualization, from device controls to test sequencers. If it was not good enough, I for sure would have switched. That said, I started coding Fortran with punchcards and used a whole lot of programming languages on 8-bit 'machines', starting with Z80-based ones. The languages ranged from Assembler to BASIC, from Turbo-Pascal to C.
LabVIEW was a major improvement because of its extensive libraries for data acqusition and analysis. One has, however, to learn a different paradigma. And you definitely need a trackball ;-))
I don't anything about LabView (or much about C/C++), but..
Do you think that graphical languages such as LabVEIW are the future of programming?
No...
Is a graphical language easier to learn than a textual language? I think that they should be about equally challenging to learn.
Easier to learn? No, but they are easier to explain and understand.
To explain a programming language you have to explain what a variable is (which is surprisingly difficult). This isn't a problem with flowgraph/nodal coding tools, like the LEGO Mindstroms programming interface, or Quartz Composer..
For example, in this is a fairly complicated LEGO Mindstroms program - it's very easy to understand what is going in... but what if you want the robot to run the INCREASEJITTER block 5 times, then drive forward for 10 seconds, then try the INCREASEJITTER loop again? Things start getting messy very quickly..
Quartz Composer is a great exmaple of this, and why I don't think graphical languages will ever "be the future"
It makes it very easy to really cool stuff (3D particle effects, with a camera controlled by the average brightness of pixels from a webcam).. but incredibly difficult to do easy things, like iterate over the elements from an XML file, or store that average pixel value into a file.
Seeing as we are partailly rooted in helping people learn, how much should we rely on prewritten modules, and how much should we try to write on our own? ("Good programmers write good code, great programmers copy great code." But isn't it worth being a good programmer, first?)
For learning, it's so much easier to both explain and understand a graphical language..
That said, I would recommend a specialised text-based language language as a progression. For example, for graphics something like Processing or NodeBox. They are "normal" languages (Processing is Java, NodeBox is Python) with very specialised, easy to use (but absurdly powerful) frameworks ingrained into them..
Importantly, they are very interactive languages, you don't have to write hundreds of lines just to get a circle onscreen.. You just type oval(100, 200, 10, 10) and press the run button, and it appears! This also makes them very easy to demonstrate and explain.
More robotics-related, even something like LOGO would be a good introduction - you type "FORWARD 1" and the turtle drives forward one box.. Type "LEFT 90" and it turns 90 degrees.. This relates to reality very simply. You can visualise what each instruction will do, then try it out and confirm it really works that way.
Show them shiney looking things, they will pickup the useful stuff they'd learn from C along the way, if they are interested or progress to the point where they need a "real" language, they'll have all that knowledge, rather than run into the syntax-error and compiling brick-wall..
It seems that if you are trying to prepare our team for a future in programming that C(++) ma be the better route. The promise of general programming languages that are built with visual building blocks has never seemed to materialize and I am beginning to wonder if they ever will. It seems that while it can be done for specific problem domains, once you get into trying to solve many general problems a text based programming language is hard to beat.
At one time I had sort of bought into the idea of executable UML but it seems that once you get past the object relationships and some of the process flows UML would be a pretty miserable way to build an app. Imagine trying to wire it all up to a GUI. I wouldn't mind being proven wrong but so far it seems unlikely we'll be point and click programming anytime soon.
I started with LabVIEW about 2 years ago and now use it all the time so may be biased but find it ideal for applications where data acquisition and control are involved.
We use LabVIEW mainly for testing where we take continuous measurements and control gas valves and ATE enclosures. This involves both digital and analogue input and outputs with signal analysis routines and process control all running from a GUI. By breaking down each part into subVIs we are able to reconfigure the tests with the click and drag of the mouse.
Not exactly the same as C/C++ but a similar implementation of measurement, control and analysis using Visual BASIC appears complex and hard to maintain by comparision.
I think the process of programming is more important than the actual coding language and you should follow the style guidelines for a graphical programming language. LabVIEW block diagrams show the flow of data (Dataflow programming) so it should be easy to see potential race conditions although I've never had any problems. If you have a C codebase then building it into a dll will allow LabVIEW to call it directly.
There are definitely merits to both choices; however, since your domain is an educational experience I think a C/C++ solution would most benefit the students. Graphical programming will always be an option but simply does not provide the functionality in an elegant manner that would make it more efficient to use than textual programming for low-level programming. This is not a bad thing - the whole point of abstraction is to allow a new understanding and view of a problem domain. The reason I believe many may be disappointed with graphical programming though is that, for any particular program, the incremental gain in going from programming in C to graphical is not nearly the same as going from assembly to C.
Knowledge of graphical programming would benefit any future programmer for sure. There will probably be opportunities in the future that only require knowledge of graphical programming and perhaps some of your students could benefit from some early experience with it. On the other hand, a solid foundation in fundamental programming concepts afforded by a textual approach will benefit all of your students and surely must be the better answer.
The team captain thinks that LabVIEW
is better for its ease of learning and
teaching. Is that true?
I doubt that would be true for any single language, or paradigm. LabView could surely be easier for people with electronics engineering background; making programs in it is "simply" drawing wires. Then again, such people might already be exposed to programming, as well.
One essential difference - apart from from the graphic - is that LV is demand based (flow) programming. You start from the outcome and tell, what is needed to get to it. Traditional programming tends to be imperative (going the other way round).
Some languages can provide the both. I crafted a multithreading library for Lua recently (Lanes) and it can be used for demand-based programming in an otherwise imperative environment. I know there are successful robots run mostly in Lua out there (Crazy Ivan at Lua Oh Six).
Have you had a look at the Microsoft Robotics Studio?
http://msdn.microsoft.com/en-us/robotics/default.aspx
It allows for visual programming (VPL):
http://msdn.microsoft.com/en-us/library/bb483047.aspx
as well as modern languages such as C#.
I encourage you to at least take a look at the tutorials.
My gripe against Labview (and Matlab in this respect) is that if you plan on embedding the code in anything other than x86 (and Labview has tools to put Labview VIs on ARMs) then you'll have to throw as much horsepower at the problem as you can because it's inefficient.
Labview is a great prototyping tool: lots of libraries, easy to string together blocks, maybe a little difficult to do advanced algorithms but there's probably a block for what you want to do. You can get functionality done quickly. But if you think you can take that VI and just put it on a device you're wrong. For instance, if you make an adder block in Labview you have two inputs and one output. What is the memory usage for that? Three variables worth of data? Two? In C or C++ you know, because you can either write z=x+y or x+=y and you know exactly what your code is doing and what the memory situation is. Memory usage can spike quickly especially because (as others have pointed out) Labview is highly parallel. So be prepared to throw more RAM than you thought at the problem. And more processing power.
In short, Labview is great for rapid prototyping but you lose too much control in other situations. If you're working with large amounts of data or limited memory/processing power then use a text-based programming language so you can control what goes on.
People always compare labview with C++ and day "oh labview is high level and it has so much built in functionality try acquiring data doing a dfft and displaying the data its so easy in labview try it in C++".
Myth 1: It's hard to get anything done with C++ its because its so low level and labview has many things already implemented.
The problem is if you are developing a robotic system in C++ you MUST use libraries like opencv , pcl .. ect and you would be even more smarter if you use a software framework designed for building robotic systems like ROS (robot operating system). Therefore you need to use a full set of tools. Infact there are more high level tools available when you use, ROS + python/c++ with libraries such as opencv and pcl. I have used labview robotics and frankly commonly used algorithms like ICP are not there and its not like you can use other libraries easily now.
Myth2: Is it easier to understand graphical programming languages
It depends on the situation. When you are coding a complicated algorithm the graphical elements will take up valuable screen space and it will be difficult to understand the method. To understand labview code you have to read over an area that is O(n^2) complexity in code you just read top to bottom.
What if you have parallel systems. ROS implements a graph based architecture based on subcriber/publisher messages implemented using callback and its pretty easy to have multiple programs running and communicating. Having individual parallel components separated makes it easier to debug. For instance stepping through parallel labview code is a nightmare because control flow jumps form one place to another. In ROS you don't explicitly 'draw out your archietecture like in labview, however you can still see it my running the command ros run rqt_graph ( which will show all connected nodes)
"The future of programming is graphical." (Think so?)
I hope not, the current implementation of labview does not allow coding using text-based methods and graphical methods. ( there is mathscript , however this is incredibly slow)
Its hard to debug because you cant hide the parallelism easily.
Its hard to read labview code because there you have to look over so much area.
Labview is great for data aq and signal processing but not experimental robotics, because most of the high level components like SLAM (simultaneous localisation and mapping), point cloud registration, point cloud processing ect are missing. Even if they do add these components and they are easy to integrate like in ROS, because labview is proprietary and expensive they will never keep up with the open source community.
In summary if labview is the future for mechatronics i am changing my career path to investment banking... If i can't enjoy my work i may as well make some money and retire early...