CallLua.cs

/*
 Demonstrates using the higher-level LuaInterface API
*/

using System;
using LuaInterface;

// adding new Lua functions is particularly easy...
public class MyClass {

    [LuaGlobal]
    public static double Sqr(double x) {
        return x*x;
    }

    [LuaGlobal]
    public static double Sum(double x, double y) {
        return x + y;
    }

    // can put into a particular table with a new name
    [LuaGlobal(Name="utils.sum",Description="sum a table of numbers")]
    public static double SumX(params double[] values) {
        double sum = 0.0;
        for (int i = 0; i < values.Length; i++)
            sum += values[i];
        return sum;
    }

    public static void Register(Lua L) {
        L.NewTable("utils");
        LuaRegistrationHelper.TaggedStaticMethods(L,typeof(MyClass));
    }

}

public class CSharp {
    public virtual string MyMethod(string s) {
        return s.ToUpper();
    }	
    
    protected virtual string Protected(string s) {
        return s + "?";
    }
	
	protected virtual bool ProtectedBool() {
		return false;
	}
    
    public static string UseMe (CSharp obj, string val) {
        Console.WriteLine("calling protected {0} {1}",obj.Protected(val),obj.ProtectedBool());        
        return obj.MyMethod(val);	
    }
}

public class RefParms {
    public void Args(out int a, out int b) {
        a = 2;
        b = 3;
    }
    
    public int ArgsI(out int a, out int b) {
        a = 2;
        b = 3;
        return 1;
    }
    
    public void ArgsVar(params object[] obj) {
        int i = (int)obj[0];	
        Console.WriteLine("cool {0}",i);
    }
    
}

public class CallLua {
    
    public static bool IsInteger(double x) {
        return Math.Ceiling(x) == x;	
    }
    

    public static void Main(string[] args) {
        Lua L = new Lua();
        
        // testing out parameters and type coercion for object[] args.
        L["obj"] = new RefParms();
        dump("void,out,out",L.DoString("return obj:Args()"));
        dump("int,out,out",L.DoString("return obj:ArgsI()"));
        L.DoString("obj:ArgsVar{1}");
        Console.WriteLine("equals {0} {1} {2}",IsInteger(2.3),IsInteger(0),IsInteger(44));
        //Environment.Exit(0);
        
        object[] res = L.DoString("return 20,'hello'","tmp");
        Console.WriteLine("returned {0} {1}",res[0],res[1]);
        
        

        L.DoString("answer = 42");
        Console.WriteLine("answer was {0}",L["answer"]);

        MyClass.Register(L);

        L.DoString(@"
        print(Sqr(4))
        print(Sum(1.2,10))
        -- please note that this isn't true varargs syntax!
        print(utils.sum {1,5,4.2})
        ");

        L.DoString("X = {1,2,3}; Y = {fred='dog',alice='cat'}");

        LuaTable X = (LuaTable)L["X"];
        Console.WriteLine("1st {0} 2nd {1}",X[1],X[2]);
        // (but no Length defined: an oversight?)
        Console.WriteLine("X[4] was nil {0}",X[4] == null);

        // only do this if the table only has string keys
        LuaTable Y = (LuaTable)L["Y"];
        foreach (string s in Y.Keys)
            Console.WriteLine("{0}={1}",s,Y[s]);

        // getting and calling functions by name
        LuaFunction f = L.GetFunction("string.gsub");
        object[] ans = f.Call("here is the dog's dog","dog","cat");
        Console.WriteLine("results '{0}' {1}",ans[0],ans[1]);

        // and it's entirely possible to do these things from Lua...
        L["L"] = L;
        L.DoString(@"
            L:DoString 'print(1,2,3)'
        ");
        
        // it is also possible to override a CLR class in Lua using luanet.make_object.
        // This defines a proxy object which will successfully fool any C# code 
        // receiving it.
         object[] R = L.DoString(@"
            luanet.load_assembly 'CallLua'  -- load this program
            local CSharp = luanet.import_type 'CSharp'
            local T = {}
            function T:MyMethod(s) 
                return s:lower()
            end
            function T:Protected(s)
                return s:upper()
            end
			function T:ProtectedBool()
				return true
			end
            luanet.make_object(T,'CSharp')
            print(CSharp.UseMe(T,'CoOl'))
			io.flush()
            return T
        ");
        // but it's still a table, and there's no way to cast it to CSharp from here...
        Console.WriteLine("type of returned value {0}",R[0].GetType());


    }
    
    static void dump(string msg, object[] values) {
        Console.WriteLine("{0}:",msg);
        foreach(object o in values) {
            if (o == null) {
                Console.WriteLine("\tnull");
            } else {
                Console.WriteLine("\t({0}) {1}",o.GetType(),o);
            }
        }
    }
    

}