add native extensions

Qrakhen.Qamp.Core/Execution/Runner.cs

@@ -368,6 +368,25 @@ public class Runner : IDisposable
         }
     }
 
+    private bool InvokeNative(Value target, NativeExtension extension, int argumentCount)
+    {
+        _logger.Method(extension);
+        if (argumentCount != extension.Parameters.Length) {
+            Error($"{extension} expects {extension.Parameters.Length} arguments, received {argumentCount}");
+            return false;
+        }
+
+        var values = new Value[argumentCount];
+        for (int i = 0; i < argumentCount; i++) {
+            values[i] = Peek(-i - 1);
+        }
+
+        Stack.Decimate(Stack.Position - argumentCount - 1);
+        Value result = extension.Callback(target, values);
+        Push(result);
+        return true;
+    }
+
     private bool Invoke(Context closure, int argumentCount)
     {
         _logger.Method();
@@ -390,9 +409,13 @@ public class Runner : IDisposable
     {
         Value value = Peek(-argumentCount - 1);
         if (!value.Is(T.Instance)) {
-            Error($"Can not call {methodName} on value of {value}");
+            NativeExtension? extension = NativeExtension.Get(value.Type, methodName);
+            if (extension == null) {
+                Error($"Could not invoke {methodName} on {value}, no method or extension by that name found for this type.");
                 return false;
             }
+            return InvokeNative(value, extension, argumentCount);
+        }
 
         Instance instance = value.Ptr.As<Instance>()!;
         if (instance.Values.TryGet(methodName, out Value method))

Qrakhen.Qamp.Core/Values/NativeExtension.cs

@@ -0,0 +1,52 @@
+using Qrakhen.Qamp.Core.Collections;
+using Qrakhen.Qamp.Core.Values.Objects;
+
+namespace Qrakhen.Qamp.Core.Values;
+
+public delegate Value ExtensionDelegate(Value target, Value[] parameters);
+
+public class NativeExtension(
+    ValueType targetType, 
+    string name, 
+    ExtensionDelegate callback,
+    string[] parameters)
+{
+    private static readonly Register<ValueType, Register<string, NativeExtension>> _register = new();
+
+    public readonly string Name = name;
+    public readonly ValueType TargetType = targetType;
+    public readonly ExtensionDelegate Callback = callback;
+    public readonly string[] Parameters = parameters.ToArray();
+
+    public static NativeExtension? Get(ValueType targetType, string name)
+    {
+        if (!_register.Has(targetType))
+            return null;
+        if (!_register[targetType].Has(name))
+            return null;
+        return _register[targetType][name];
+    }
+
+    public static void Register(ValueType targetType, 
+                                string name, 
+                                ExtensionDelegate callback, 
+                                params string[] parameters)
+    {
+        if (!_register.Has(targetType))
+            _register.Add(targetType, new());
+        if (_register[targetType].Has(name))
+            throw new QampException($"Extension {name} already exists for type {targetType}.");
+        _register[targetType].Add(name, new NativeExtension(targetType, name, callback, parameters));
+    }
+
+    static NativeExtension()
+    {
+        Register(ValueType.String, "Length", (v, p) => new Value((long)v.Ptr.As<Objects.String>()!.Value!.Length), []);
+        Register(ValueType.String, "IndexOf", (v, p) => new Value((long)v.Ptr.As<Objects.String>()!.Value!.IndexOf(p[0].Ptr.As<Objects.String>()!.Value!)), [ "needle" ]);
+    }
+
+    public override string ToString()
+    {
+        return $"{TargetType}.{Name}({string.Join(", ", Parameters)}) (NativeExtension)";
+    }
+}

Qrakhen.Qamp.Core/Values/Objects/Extension.cs

@@ -0,0 +1,11 @@
+namespace Qrakhen.Qamp.Core.Values.Objects;
+
+public class Extension(ValueType targetType, Function function) : Context(function)
+{
+    public ValueType TargetType = targetType;
+
+    public override string ToString()
+    {
+        return $"{TargetType}.{Function.Name}() (Extension)";
+    }
+}

Qrakhen.Qamp.Core/Values/Objects/Native.cs

@@ -0,0 +1,9 @@
+namespace Qrakhen.Qamp.Core.Values.Objects;
+
+public class Native(string name) : Class(name)
+{
+    public override string ToString()
+    {
+        return $"{Name} (Native)";
+    }
+}

Qrakhen.Qamp.Core/Values/ValueExtensions.cs

@@ -4,8 +4,5 @@ namespace Qrakhen.Qamp.Core.Values;
 
 internal static class ValueExtensions
 {
-    public static Value ExecuteOperation(this Value value, Value other, OpCode operation)
+    
-    {
-        return new Value();
-    }
 }