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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....
Are there any tools available for generating RDF from natural language? A list of RDFizers compiled by the SIMILE project only mentions one, the Monrai Cypher. Unfortunately, it seems to have been a proprietary tool developed by Monrai Technologies, which has since disappeared, and I can't find any download links. Has anyone seen anything similar?
You want some ontology learning and population tools.
This online article lists 4 different systems:
Text2Onto,
Abraxas,
KnowItAll,
OntoLearn
You may want to check out the book; it reviews several ontology learning tools as well:
Ontology learning from text: methods, evaluation and applications, by Paul Buitelaar, Philipp Cimiano, Bernardo Magnini
You might look into OpenCalias, Zemanta and Hakia which all have nice APIs for extracting semantic data out of internet resources. Not familiar with Monrai Cypher, but possibly these might help.
you could use the python nltk
to parse the text and emit the rdf tripplets
I'd like to implement a Lisp interpreter in a Lisp dialect mainly as a learning exercise. The one thing I'm thrown off by is just how many choices there are in this area. Primarily, I'm a bit more interested in learning about some of the Lisps that have been around a while (like Scheme or Common Lisp). I don't want to use Clojure to do this for the sheer fact that I've already used it. :-)
So is one of the flavors any better than the others at parsing? And do you think it's a good idea to say implement Scheme in Common Lisp (or vice versa)? Or will there be enough differences between the two to throw me off?
And if it makes any difference, I'd like something that's cross-platform. I have a Windows PC, a Mac, and a Linux box, and I could end up writing this on any of them.
There are some books about that:
SICP chapter 4 and 5
PAIP, chapter 5
LiSP, the whole book explains implementing Lisp
Anatomy of Lisp, old classic about implementing Lisp
All of the above books are highly recommended, though Anatomy of Lisp is oldish, hard to get and hard to read.
Both Scheme and Common Lisp are fine for your task.
Implementing Common Lisp is a larger task, since the language is larger. Usually one implements Common Lisp better in Common Lisp, since there are Common Lisp libraries that can be used for new Common Lisp implementations. ;-)
PLT Scheme is an excellent platform for experimenting with programming languages, especially Lispy languages. PLT has an extensible parser (usually called a reader in Scheme) that provides reader macros to manipulate the built in syntax; or you can completely replace the reader with your own. If you'd rather use traditional lex/yacc style parsers and lexers, PLT comes with a parser-tools module that provides those, too. As a bonus, it has comprehensive documentation and a repository for third-party packages (two things that are missing from a lot of Schemes).
The reference implementation of Arc (arclanguage.org) is a fairly simple and readable
example of building a language that compiles to Scheme. It uses PLT's reader mostly, with a couple of reader macros to change the bits of Scheme syntax that differ from Arc's. There's also a JavaScript implementation available from PLT's package repository (planet.plt-scheme.org) if you want to see how to implement a non-Lisp language.
Hi I'd like to pick up one FP language (it's always a pain when you work in a position that does not require you learn much), and after doing some research, I felt Erlang and OCaml are the two that I'd really like to get my feet wet for the following reasons:
1) I work mainly on high-availability web server back-end system in C++. I heard Erlang is a great fix in scalability and fault-tolerance. Though I don't think my current company will have any project in Erlang, I feel Erlang may be a good language for my long term career development.
2) I have a co-worker who is really good at OCaml, I mean he is really good at it (but he does not work on that for his daily work now. He maintains several library). So I figured that he may be a good resource if I learn OCaml.
My interests are mainly on distributed systems (my current work is some midldle-ware development work) and high-performance computing (guess what, I had a couple of years graduate school research on it, in particular PDE in Financial applications -- so I always felt I may go back to do some finance modeling work maybe sometime later)
Any suggestions? Please don't suggest "learn both", as I am not that smart :-)
Thanks
Ocaml is a great language -- one of my favorites -- but if your interest is distributed systems than I'd recommend going with Erlang, which is head and shoulders ahead of the other FP languages with regards to distributed systems (although there's an offshoot of Ocaml called Jocaml which has some interesting aspects).
Ocaml is weaker even when just looking at parallelism, given its underlying architecture. Both Haskell and Clojure have better stories here, imho. (That said: once you get one FP language, you'll be able to carry the fundamental principles to other languages pretty easily, and they might be useful in the future. Both Scala and Clojure could easily sneak their way into organizations by virtue of the JVM.)
I think Ocaml is a great way to get started in FP, and Erlang is not very difficult once you have the basic FP concepts down.
But the suggestion from 'aneccodeal' is fantastic-- i.e., if you are interested in Ocaml and have a friend who is already strong in it, by all means develop a concurrency (perhaps MPI) library for it.
Keep in mind, however, that one of the barriers to making Ocaml concurrent is the lack of concurrent garbage collection (or so I have read).
If you have a co-worker who is "really good" with OCaml then it sounds like you have a great resource assuming that s/he is willing to answer your questions. It's always easier to learn when there's someone knowledgeable around that you can ask questions of if you get stuck.
Yes it's true that OCaml doesn't have the best story when it comes to parallelism, but there are ways to get parallelism in OCaml (fork-based seems to be the most common - checkout prelude.ml which includes things like parallel map: http://github.com/kig/preludeml/tree/master ). Also, it seems that Erlang's Actor-based concurrency is really fairly easy to duplicate in other languages. Maybe you and your co-worker could work on a project to develop an Actor-based concurrency library for OCaml? That would give you a nice learning project that you co-worker would probably find interesting enough to work on with you... in addition you could end up creating something useful for the entire OCaml community.
I would also consider to look at F# (especially when VS 2010 is out).
Learning a new language is a lot easier and more convenient with a nice IDE.
F# and OCaml are very similar as you can see in other SO threads (e.g. here)
What tools are available for metamodelling?
Especially for developing diagram editors, at the moment trying out Eclipse GMF
Wondering what other options are out there?
Any comparison available?
Your question is simply too broad for a single answer - due to many aspects.
First, meta-modelling is not a set term, but rather a very fuzzy thing, including modelling models of models and reaching out to terms like MDA.
Second, there are numerous options to developing diagram editors - going the Eclipse way is surely a nice option.
To get you at least started in the Eclipse department:
have a look at MOF, that is architecture for "meta-modelling" from the OMG (the guys, that maintain UML)
from there approach EMOF, a sub set which is supported by the Eclipse Modelling Framework in the incarnation of Ecore.
building something on top of GMF might be indeed a good idea, because that's the way existing diagram editors for the Eclipse platform take (e.g. Omondo's EclipseUML)
there are a lot of tools existing in the Eclipse environment, that can utilize Ecore - I simply hope, that GMF builts on top of Ecore itself.
Dia has an API for this - I was able to fairly trivially frig their UML editor into a basic ER modelling tool by changing the arrow styles. With a DB reversengineering tool I found in sourceforge (took the schema and spat out dia files) you could use this to document databases. While what I did was fairly trivial, the API was quite straightforward and it didn't take me that long to work out how to make the change.
If you're of a mind to try out Smalltalk There used to be a Smalltalk meta-case framework called DOME which does this sort of thing. If you download VisualWorks, DOME is one of the contributed packages.
GMF is a nice example. At the core of this sits EMF/Ecore, like computerkram sais. Ecore is also used for the base of Eclipse's UML2 . The prestige use case and proof of concept for GMF is certainly UML2 Tools.
Although generally a UML tool, I would look at StarUML. It supports additional modules beyond what are already built in. If it doesn't have what you need built in or as a module, I supposed you could make your own, but I don't know how difficult that is.
Meta-modeling is mostly done in Smalltalk.
You might want to take a look at MOOSE (http://moose.unibe.ch). There are a lot of tools being developed for program understanding. Most are Smalltalk based. There is also some java and c++ work.
Two of the most impressive tools are CodeCity and Mondrian. CodeCity can visualize code development over time, Mondrian provides scriptable visualization technology.
And of course there is the classic HotDraw, which is also available in java.
For web development there is also Magritte, providing meta-descriptions for Seaside.
I would strongly recommend you look into DSM (Domain Specific Modeling) as a general topic, meta-modeling is directly related. There are eclipse based tools like GMF that currently require java coding, but integrate nicely with other eclipse tools and UML. However there are two other classes out there.
MetaCase which I will call a pure DSM tool as it focuses on allowing a developer/modeler with out nearly as much coding create a usable graphical model. Additionally it can be easily deployed for others to use. GMF and Microsoft's Beta software factory/DSM tool fall into this category.
Pure Meta-modeling tools which are not intended for DSM tooling, code generation, and the like. I do not follow these tools as closely as I am interested in applications that generate tooling for SMEs, Domain Experts, and others to use and contribute value to an active project not modeling for models sake, or just documentation and theory.
If you want to learn more about number 1, the tooling applications for DSMs/Meta-modeling, then check out my post "DSMForum.org great resources, worth a look." or just navigate directly to the DSMForum.org
In case you are interested in something that is related to modelling and not generation of code, have a look at adoxx.org. As a metamodelling platform it does provide functionalities and mechanisms to quickly develop your own DSL and allows you to focus on the models needs (business requirements, conceptual level design/specification). There is an active community from academia and practice involved developing prototypical as well as commercial application based on the platform. Could be interesting ...