I have a little game written in C#. It uses a database as back-end. It's
a trading card game, and I wanted to implement the function of the cards as a script.
What I mean is that I essentially have an interface, ICard, which a card class implements (public class Card056: ICard) and which contains a function that is called by the game.
Now, to make the thing maintainable/moddable, I would like to have the class for each card as source code in the database and essentially compile it on first use. So when I have to add/change a card, I'll just add it to the database and tell my application to refresh, without needing any assembly deployment (especially since we would be talking about 1 assembly per card which means hundreds of assemblies).
Is that possible? Register a class from a source file and then instantiate it, etc.
ICard Cards[current] = new MyGame.CardLibrary.Card056();
Cards[current].OnEnterPlay(ref currentGameState);
The language is C# but extra bonus if it's possible to write the script in any .NET language.
Oleg Shilo's C# Script solution (at The Code Project) really is a great introduction to providing script abilities in your application.
A different approach would be to consider a language that is specifically built for scripting, such as IronRuby, IronPython, or Lua.
IronPython and IronRuby are both available today.
For a guide to embedding IronPython read
How to embed IronPython script support in your existing app in 10 easy steps.
Lua is a scripting language commonly used in games. There is a Lua compiler for .NET, available from CodePlex -- http://www.codeplex.com/Nua
That codebase is a great read if you want to learn about building a compiler in .NET.
A different angle altogether is to try PowerShell. There are numerous examples of embedding PowerShell into an application -- here's a thorough project on the topic:
Powershell Tunnel
You might be able to use IronRuby for that.
Otherwise I'd suggest you have a directory where you place precompiled assemblies. Then you could have a reference in the DB to the assembly and class, and use reflection to load the proper assemblies at runtime.
If you really want to compile at run-time you could use the CodeDOM, then you could use reflection to load the dynamic assembly. Microsoft documentation article which might help.
If you don't want to use the DLR you can use Boo (which has an interpreter) or you could consider the Script.NET (S#) project on CodePlex. With the Boo solution you can choose between compiled scripts or using the interpreter, and Boo makes a nice scripting language, has a flexible syntax and an extensible language via its open compiler architecture. Script.NET looks nice too, though, and you could easily extend that language as well as its an open source project and uses a very friendly Compiler Generator (Irony.net).
You could use any of the DLR languages, which provide a way to really easily host your own scripting platform. However, you don't have to use a scripting language for this. You could use C# and compile it with the C# code provider. As long as you load it in its own AppDomain, you can load and unload it to your heart's content.
I'd suggest using LuaInterface as it has fully implemented Lua where it appears that Nua is not complete and likely does not implement some very useful functionality (coroutines, etc).
If you want to use some of the outside prepacked Lua modules, I'd suggest using something along the lines of 1.5.x as opposed to the 2.x series that builds fully managed code and cannot expose the necessary C API.
I'm using LuaInterface1.3 + Lua 5.0 for a NET 1.1 application.
The issue with Boo is that every time you parse/compile/eval your code on the fly, it creates a set of boo classes so you will get memory leaks.
Lua in the other hand, does not do that, so it's very very stable and works wonderful (I can pass objects from C# to Lua and backwards).
So far I haven't put it in PROD yet, but seems very promising.
I did have memory leaks issues in PROD using LuaInterface + Lua 5.0, therefore I used Lua 5.2 and linked directly into C# with DllImport. The memory leaks were inside the LuaInterface library.
Lua 5.2: from http://luabinaries.sourceforge.net and http://sourceforge.net/projects/luabinaries/files/5.2/Windows%20Libraries/Dynamic/lua-5.2_Win32_dll7_lib.zip/download
Once I did this, all my memory leaks were gone and the application was very stable.
The main application that my division sells does something very similar to provide client customisations (which means that I can't post any source). We have a C# application that loads dynamic VB.NET scripts (although any .NET language could be easily supported - VB was chosen because the customisation team came from an ASP background).
Using .NET's CodeDom we compile the scripts from the database, using the VB CodeDomProvider (annoyingly it defaults to .NET 2, if you want to support 3.5 features you need to pass a dictionary with "CompilerVersion" = "v3.5" to its constructor). Use the CodeDomProvider.CompileAssemblyFromSource method to compile it (you can pass settings to force it to compile in memory only.
This would result in hundreds of assemblies in memory, but you could put all the dynamic classes' code together into a single assembly, and recompile the whole lot when any change. This has the advantage that you could add a flag to compile on disk with a PDB for when you're testing, allowing you to debug through the dynamic code.
Yes, I thought about that, but I soon figured out that another Domain-Specific-Language (DSL) would be a bit too much.
Essentially, they need to interact with my gamestate in possibly unpredictable ways. For example, a card could have a rule "When this cards enter play, all your undead minions gain +3 attack against flying enemies, except when the enemy is blessed". As trading card games are turn based, the GameState Manager will fire OnStageX events and let the cards modify other cards or the GameState in whatever way the card needs.
If I try to create a DSL, I have to implement a rather large feature set and possibly constantly update it, which shifts the maintenance work to another part without actually removing it.
That's why I wanted to stay with a "real" .NET language to essentially be able to just fire the event and let the card manipulate the gamestate in whatever way (within the limits of the code access security).
The next version of .NET (5.0?) has had a lot of talk about opening the "compiler as a service" which would make things like direct script evaluation possible.
Related
I making a simple game engine with C# (in VB 2008, mostly for myself). There is a main application which does the graphics and stuff, and most of the data from the actually game will be in a dll generated with the tools I would give to the game designer.
I've heard a lot about C# being great for scripting, (and it looks like it would suit my needs better than any other way) but I can't really find an answer of exactly how it's done. I ran into this problem:
I obviously don't want to give out my source code for the main exe but it will contain all the main methods needed for scripting (because they act on the main exe).
How could a dll be generated when it doesn't have a definition of the methods it will be calling in the parent exe? The main exe will have the dll as a dependency to use it. That means that the dll can't have a dependency on the exe which would cause a loop.
I could create another dll that both the exe and the library would use, but then the methods in there wouldn't be able to act directly on the main exe using it.
The only logical solution I came up with is this:
A dll with the bare bones of the class I need.
A dll that contains the game data. This will have a class inherited from dll A.
Exe dependent on both A and B. It will override the A methods that are in B to behave the way that it should.
This doesn't seem too elegant though.
I've seen a lot of words in my research (MAF, MEF, Roslyn, etc.) before I got too tired to read further. I have spent several hours on this alone.
In your opinion, how should I go about doing this? Is there something I'm overlooking?
I don't know where you heard C# is 'great' for scripting. The half-baked attempt of Rosyln is not really "scripting".
Why not try one of those DLR languages - like IronPython and IronRuby?
Also there is Lua binding for .NET.. Most game developers these days do their scripting in Lua. So the modder community will definitely love your Game Engine, if you plan to keep it closed source.
It's sounds like you're mixing up extensibility through dlls and extensibility through scripting.
Let's take the dll approach first.
The standard way to implement this is quite close to what you've outlined:
Have an interfaces.dll
Your entry point dll will take a dependency on the interfaces.dll
Extension dlls will take a dependency on the interfaces.dll
At runtime, to extend main, scan the entention dll for classes which implement the needed interfaces in interfaces.dll, invoke the methods as needed.
For scripting, you'll typically want to use a scripting language - powershell is popular for .Net, and there are also some experiments with JavaScript
I am starting with game dev using Unity3d and I can see there's 3 supported languages for creating scripts: C#, unityscript and Boo...
although, coming from a web-design past I am obviously used with javascript, but after few attempts I could notice Unity3d doesn't really have full support to the script language and some elements like new Date().valueOf() and some other statements within methods such as the attribute arguments and many other won't work properly, also it seems my file can't have a wrapper method that envolves all the other methods like:
(function (scope) {
function Start() {
...
}
...
}(this));
and when using something like new Date().valueOf() which is valid in JS I get:
MissingMethodException: Method not found: 'System.DateTime.valueOf'. Boo.Lang.Runtime.DynamicDispatching.MethodDispatcherFactory.ProduceExtensionDispatcher ()
So perhaps the compiler turns that initial 'unityscript' code into Boo language? so perhaps Boo is the right 'native' choice and maybe unityscript itself isn't the best way to go when developing unity3d apps?
I was thinking on a language that has full support to all known native classes and methods which will work without problem?
Sorry for any errors mentioned above and please let me know what you think.
Unity doesn't use 'real' Javascript per se. See:
http://forum.unity3d.com/threads/1117-Javascript-Version
UnityScript is based on javascript 2.0. There are a few things missing (switch statements, etc.), but they get half the speed of C++, which is way faster than Mozilla.
Once you get used to it, developing in 'JS' for unity is very very fast and flexible...but of course, if you're going to develop native components, or interface to anything in C, you'll need to use C# (in the end, C# is not difficult to learn).
If you want to be a developer in Unity and build a career on it, learn C# and use it - don't waste your time with UnityScript. You can use C# outside of Unity for programming. If your main career is already web development (or will be), then continue using javascript because ultimately C# and UnityScript have the same functionality but C# is much more widely used for programing games and applications.
The majority of the assets on the store that I have used are C# or offer both JS and C#. Mixing between the languages creates serious dependency problems because in order to use a class in either language it has to already have been processed by the Unity script loading order. To use a Javascript defined class in C#, that script file must have been processed prior to the C# script file. If the javscript class then later needs something from the C# class, you would have to find ways around it because its simply no longer possible from the javascript file. Unity has ways to define the script order.
I thought that I would warn you about mixing C# with UnityScript because if you don't focus on one or the other, you will run into this problem. Ultimately, C# is the middle ground between ambiguous languages like VB and JavaScript, and pedantic languages like C++ (I have a C/C++ background of about 10 years).
Your title "What is the best xxx" leads to opinionated answers, but I am trying to give the best advice possible without being subjective. C# will allow you to continue, even if Unity were to go away a year from now. UnityScript/JavaScript would only allow you to move into being a web developer. A C# developer can easily move into UnityScript/JavaScript, but the reverse is much harder (not impossible, just more difficult).
You should use c#. It is popular, mature, native to .NET. c# is what big teams use. Learning c# will be useful in the future. JS in Unity3D is not real JS as already mentioned and nobody heard of Boo.
JS is the most popular language for use with Unity. But the language is implemented in Mono, and so any restrictions in that implementation are going to affect Unity scripts too.
I don't know how the Mono implementation of JS works, but judging from the error message, it uses datatypes initially defined for Boo, at least. However, that doesn't mean that JS is "turned into Boo". Both are compiled into the same bytecode, which is JIT'ed and run by the Mono runtime. So neither language is "more native" than the other.
Checkout advantages and disadvantages of using c# and Java script from here.
C# is little bit faster than JavaScript and you get extra features provided by C#. You can get peoples opinion from here.
Developing with c# has advantage of Visual Studio 2010. It provides better code completion feature than Mono develop.
In JavaScript only, variables can have an unspecified type. This only occurs if you do not assign a value while declaring the variable.
Performance is slower with dynamically typed variables, and you can run into casting problems. Iif this is a concern, use #pragma strict.
I'm doing a POC (Proof of concept) for a little open source project, to integrate Lua into c# looks pretty straight forward, but for this project we want to go a little further. We want to be able to edit Lua scripts from within our C# program (WPF client but we can go for winforms if that what it takes), the IDE needs basic code completion and that we can add our C# objects and methods (The ones you will be able to reach from the Lua scripts while running) so they will be auto completed.. Are they such a API available for C#?
edit: Schollii wanted some example code that i want code completion for
while true do
Mouse:setY(TrackIR:getPitch())
end
where Mouse and TrackIR are c# objects accessible from Lua script
If you want to integrate a Lua editor with syntax highlighting C#, IMO the easiest way is to go for the Scintilla control, which is available in C# through ScintillaNET. It already contains highlighter for the Lua language, and is relatively easy to embed and use.
For interfacing Lua with C#, you can use LuaInterface and back. See this question for documentation links.
Code completion will not be an easy task if you require completion beyond the standard library, which can be described in a simple dictionary. With Lua being a dynamic language, it is not trivial to deduce the contents of a variable before actually running the code up to a given point - it is not impossible, take a look at lua-inspect which is available for SciTE and ViM and allows code inspection (but it's not perfect).
If you want to try code in a running environment - i.e. you have a Lua state running with modules loaded and variables set - you can get inspired by Advanced Readline Support patch at LuaPowerPatches and adapt it to your enviroment in C#. It supports among other:
Completion of keywords and global variable names.
Recursive and metatable-aware completion of variable names.
Context sensitive delimiter completion.
It seems you just want an embeddable editor that can have code completion and syntax highlighting, preferably WPF based. It doesn't need to explicitly support Lua.
Have a look at Avalon Edit. Here is an article about it
You will have to implement the highlighting file and completions yourself within the framework it provides - but that looks easy enough.
I am not aware of any such libs. Some tool you will likely need/find useful are Luainterface and some open-source Lua editors that provide code comppletion such as blua and Scite. Note that code completion comes in different flavors, each with pros/cons in terms of power, ease of implementation, etc. For instance if you just want to provide a list of possible words that correspond to objects in global Lua namespace then you don't need much at all; if OTOH you want code completion to work with table fields and objects and various levels of nesting, work will be much increased.
I'm trying wrap my head around all of the different scripting technologies for Windows (what are they, and which are the most common) and ultimately to figure out what type of scripting to add to my application.
I've read that with .NET 4 it's easy to make your program scriptable via dynamic languages like IronRuby and IronPython (or even VB or C# which might be more confusing for a user?) My understanding is that pre .NET 4 the way to add scripting support for your application was to make it a COM/OLE object so people could use vbscript, winbatch, shell scripts, or another scripting language (or really any language that supported COM) to control your application? What are the common scripting languages use? I've heard a lot of people talk about VB for Applications. Is that a dynamic language or a compiled language and to allow my application to be scriptable via VB for Applications would I have to support COM/OLE? I think I'm leaning towards supporting IronRuby and IronPython since it seems simple to implement support for them, but can those languages also be used to script Windows or other applications in general (and thus scripts for your application could have more features than what you laid out)? How would you go about designing your application to be scriptable?
I know that seems like a thousands questions, but really what I'm looking for is just an explanation of the scripting technologies for windows (what are the main differences, how frequently are they used) and which ones are the most common/standard to support when making your application scriptable?
Thanks in advance everyone!!
I think it depends on what you are trying to do. Are you trying to create dynamic objects in your apppool or view the values of something in your memory. If you need access to you objects then I would say maybe you could put a scripting window in your program. If you are just trying to configure certain aspects of you program you and look at adding modules to windows powershell for your admins. That seems to be what microsoft is doing for things like sharepoint and sql server. I would look up if powershell can fit your needs so that users can use the language they are confortable with and write there own scripts but if not then take a look at adding one of the dynamic languages to your app. If slashdot is to be believed today then Microsoft is not going to be persuing them as agressively.
Scrolling Game Development Kit 2 will actually compile code entered in the UI rather than interpret it as script. (It uses the C# compiler provided with the framework.) It can then run and reflect on that code at runtime. Have you considered a solution like that?
We all knows that C# is a static language while Python is a dynamic language. But I want to know what are the features that Python has and c# does not. Also, is it advisable/beneficial to use IronPython with c# in the same application?
Also what points I should focus to learn before I try to convince my boss to use IronPython?
In other words, what points I can give to my boss to convince him to use IronPython?
Don't. If you don't know why you should use a new tool and for what, don't try to convice anybody to use it. At work, you should try to solve problems with the best tools for the task, not throw the fanciest tools avaiable at your problems just because they're fancy.
Learn IronPython, maybe make a small side project in it, find out what the strenghts are. Then if you think these strengths are useful for the project you're working on (e.g. for "glue code", plugins, macros etc.), convice your boss to use them.
One of IronPython's key advantages is in its function as an extensibility layer to application frameworks written in a .NET language. It is relatively simple to integrate an IronPython interpreter into an existing .NET application framework. Once in place, downstream developers can use scripts written in IronPython that interact with .NET objects in the framework, thereby extending the functionality in the framework's interface, without having to change any of the framework's code base.
IronPython makes extensive use of reflection. When passed in a reference to a .NET object, it will automatically import the types and methods available to that object. This results in a highly intuitive experience when working with .NET objects from within an IronPython script.
Source - Wikipedia