Closure

using SolarSharp.Interpreter;
using SolarSharp.Interpreter.DataTypes;

var script = new Script();

// Define a function in Lua
script.DoString(@"
    function add(a, b)
        return a + b
    end
    
    function makeCounter()
        local count = 0
        return function()
            count = count + 1
            return count
        end
    end
");

// Get and call a simple function
Closure addFunc = script.Globals.Get("add").Function;
LuaValue result = addFunc.Call(10, 20);
Console.WriteLine(result.Number); // 30

// Use as a delegate
ScriptFunctionDelegate<double> addDel = addFunc.GetDelegate<double>();
double sum = addDel(5, 7); // 12.0

// Get a closure with upvalues
LuaValue counterFunc = script.Call(script.Globals.Get("makeCounter"));
Closure counter = counterFunc.Function;

Console.WriteLine($"Upvalues: {counter.GetUpvaluesCount()}"); // 1 (count variable)
Console.WriteLine($"Upvalue name: {counter.GetUpvalueName(0)}"); // "count"

// Call the counter multiple times
Console.WriteLine(counter.Call().Number); // 1
Console.WriteLine(counter.Call().Number); // 2
Console.WriteLine(counter.Call().Number); // 3

// Inspect and modify upvalue
LuaValue countUpvalue = counter.GetUpvalue(0);
Console.WriteLine($"Current count: {countUpvalue.Number}");
countUpvalue.Assign(LuaValue.NewNumber(100));
Console.WriteLine(counter.Call().Number); // 101