Adding scripting functionality to .NET applications

Question

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.

Answer 1

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

Answer 2

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.