/// <summary>
		/// Used by compiler and full-reflect.
		/// </summary>
		internal DPropertyDesc(DTypeDesc/*!*/ declaringType, PhpMemberAttributes memberAttributes)
			: base(declaringType, memberAttributes)
		{
			Debug.Assert(declaringType != null);
			this._getterStub = null; // to be generated on demand
			this._setterStub = null; // to be generated on demand
		}

 /// <summary>
 /// Initialize the ClassCOntextHolder with a known DTypeDesc.
 /// Use UnknownTypeDesc.Singleton to specify an unknown caller. In this case the caller will be determined when needed.
 /// </summary>
 /// <param name="caller"></param>
 public ClassContextHolder(DTypeDesc caller)
 {
     if (caller == null || !caller.IsUnknown)
     {
         ClassContext = caller;
     }
 }

 public PhpGetMemberBinder(string fieldName, DTypeDesc classContext, bool issetSemantics, Type/*!*/returnType)
 {
     this._fieldName = fieldName;
     this._classContext = classContext;
     this._issetSemantics = issetSemantics;
     this._returnType = returnType;
 }

		public static DObject GetTypeOf(NamingContext/*!*/ namingContext, DTypeDesc caller, object typeNameOrObject)
		{
			ScriptContext context = ScriptContext.CurrentContext;
			DTypeDesc type = PhpObjects.ClassNameOrObjectToType(context, namingContext, caller, typeNameOrObject, true);
			if (type == null) return null;

			return ClrObject.Create(type.RealType);
		}

        public static void Call(NamingContext namingContext, DTypeDesc caller, string className)
        {
            ScriptContext context = ScriptContext.CurrentContext;

            // If class isn't defined autoload functions are called automatically until class is declared
            if (context.IsSplAutoloadEnabled)
                ScriptContext.CurrentContext.ResolveType(className, namingContext, caller, null, ResolveTypeFlags.UseAutoload);
        }

		/// <param name="context">A script context to get declarators from.</param>
		/// <param name="caller">A current type context.</param>
		public TypesProvider(ScriptContext/*!*/ context, DTypeDesc/*!*/ caller)
		{
			Debug.Assert(context != null && caller != null);

			this.context = context;
			this.caller = caller;
			Debug.WriteLine("PROVIDER", "created");
		}

		/// <summary>
		/// Used by compiler through subclasses (<paramref name="arglessStub"/> is <B>null</B> then).
		/// Called by a declaring helper at run-time.
		/// </summary>
        /// <param name="declaringType">The declaring type. Can be null.</param>
        /// <param name="memberAttributes">Attributes of the function.</param>
        /// <param name="arglessStub">The stub to be called. Cannot be null.</param>
        /// <param name="needsIndex">True to allocate <see cref="Index"/>. Usable for preserved descs, for global functions that can be reused.</param>
		internal DRoutineDesc(DTypeDesc/*!*/ declaringType, PhpMemberAttributes memberAttributes, RoutineDelegate arglessStub, bool needsIndex)
			: base(declaringType, memberAttributes)
		{
			Debug.Assert(declaringType != null);
			this._arglessStub = arglessStub;

            // allocate an index, only for preserved descs
            if (needsIndex) // assign an index only if needed (save indexes, since they cause prealocation of larger BitArray)
                this.Index = System.Threading.Interlocked.Increment(ref LastIndex);
		}

		// variables may be null when the code is global

		protected LinqContext(DObject outerType, Dictionary<string, object> variables, ScriptContext/*!*/ context, DTypeDesc typeHandle)
		{
			if (context == null)
				throw new ArgumentNullException("context");
			
			this.variables = variables;
			this.outerType = outerType;
			this.context = context;
			this.typeHandle = typeHandle;
		}

        /// <summary>
        /// Creates appropriate binder according to paramaters specified
        /// </summary>
        /// <param name="methodName">Name of the method known during binder creation.</param>
        /// <param name="genericParamsCount">Number of generic type arguments of the method</param>
        /// <param name="paramsCount">Number of arguments of the method</param>
        /// <param name="callerClassContext">TypeDesc of the class that is calling this method</param>
        /// <param name="returnType">Type which is expected from the call site to return</param>
        /// <returns>Return appropriate binder derived from PhpInvokeMemberBinder</returns>
        public static PhpInvokeMemberBinder Create(string methodName, int genericParamsCount, int paramsCount, DTypeDesc callerClassContext, Type returnType)
        {
            if (methodName == null)
            {
                return new PhpIndirectInvokeMemberBinder(genericParamsCount, paramsCount, callerClassContext, returnType);
            }
            else
            {
                return new PhpInvokeMemberBinder(methodName, genericParamsCount, paramsCount, callerClassContext, returnType);
            }

        }

		public static object CallUserFunction(DTypeDesc caller, PhpCallback function, params object[] args)
		{
			if (function == null)
			{
				PhpException.ArgumentNull("function");
				return null;
			}
			if (function.IsInvalid) return null;

			// invoke the callback:
			return PhpVariable.Dereference(function.Invoke(caller, args));
		}

        static PhpReference notsetOperation(DObject self, string name, DTypeDesc caller, PhpReference refrnc)
        {
            bool getter_exists;
            // the CT property has been unset -> try to invoke __get
            PhpReference get_ref = self.InvokeGetterRef(name, caller, out getter_exists);
            if (getter_exists) return get_ref ?? new PhpReference();

            Debug.Assert(refrnc != null);

            refrnc.IsAliased = true;
            refrnc.IsSet = true;

            return refrnc;
        }

        public static object CallUserFunctionArray(DTypeDesc caller, PhpCallback function, PhpArray args)
		{
			object[] args_array;

            if (args != null)
            {
                args_array = new object[args.Count];
                args.CopyValuesTo(args_array, 0);
            }
            else
            {
                args_array = ArrayUtils.EmptyObjects;
            }

			return CallUserFunction(caller, function, args_array);
		}

            public void BindOrBiteMyLegsOff(DTypeDesc caller, NamingContext namingContext)
            {
                if (Callback != null)
                {
                    if (Callback.TargetInstance == null && Parser._handlerObject != null)
                        _currentCallback = new PhpCallback(Parser._handlerObject, Callback.RoutineName);
                    else
                        _currentCallback = Callback;

                    Bound = _currentCallback.Bind(true, caller, namingContext);
                }
                else
                {
                    Bound = false;
                }
            }

        public static CallSiteBinder/*!*/MethodCall(string methodName, int genericParamsCount, int paramsCount, DTypeDesc classContext, Type/*!*/returnType)
        {
            // CallSite< Func< CallSite, object /*target instance*/, ScriptContext, {args}*/*method call arguments*/, (DTypeDesc)?/*class context, iff <classContext>.IsUnknown*/, (object)?/*method name, iff <methodName>==null*/, <returnType> > >

            PhpInvokeBinderKey key = new PhpInvokeBinderKey(methodName, genericParamsCount, paramsCount, classContext, returnType);

            lock (invokeMemberBinders)
            {
                PhpInvokeMemberBinder res;
                if (!invokeMemberBinders.TryGetValue(key.ToString(), out res))
                {
                    invokeMemberBinders[key.ToString()] = res = PhpBaseInvokeMemberBinder.Create(methodName, genericParamsCount, paramsCount, classContext, returnType);
                }

                return res;
            }

        }

        /// <summary>
        /// Generates Expression that throws a 'Protected method called' or 'Private method called' <see cref="PhpException"/>.
        /// </summary>
        /// <param name="method">The <see cref="DRoutineDesc"/>.</param>
        /// <param name="callerContext">The caller that was passed to method lookup or <B>null</B>
        /// if it should be determined by this method (by tracing the stack).</param>
        /// <remarks>
        /// This method is intended to be called after <see cref="DTypeDesc.GetMethod"/> has returned
        /// <see cref="GetMemberResult.BadVisibility"/> while performing a method lookup.
        /// </remarks>
        public static Expression/*!*/ ThrowVisibilityError(DRoutineDesc/*!*/ method, DTypeDesc/*!*/ callerContext)
        {
            if (method.IsProtected)
            {
                return ThrowError("protected_method_called",
                                  method.DeclaringType.MakeFullName(),
                                  method.MakeFullName(),
                                  callerContext == null ? String.Empty : callerContext.MakeFullName());
            }
            else if (method.IsPrivate)
            {
                return ThrowError("private_method_called",
                                  method.DeclaringType.MakeFullName(),
                                  method.MakeFullName(),
                                  callerContext == null ? String.Empty : callerContext.MakeFullName());
            }

            throw new NotImplementedException();
        }

		/// <summary>
		/// Calls the method referred by <paramref name="methodName"/> from the user defined
		/// object <paramref name="classNameOrObject"/> with parameters <paramref name="args"/>.
		/// </summary>
        /// <param name="caller">DTypeDesc of the caller's class context. Can be UnknownTypeDesc.</param>
        /// <param name="methodName">The name of the method.</param>
		/// <param name="classNameOrObject">An instance to invoke the method on or a class name.</param>
		/// <param name="args">Parameters to invoke the method with.</param>
		/// <returns>The method's return value (always dereferenced).</returns>
        internal static object CallUserMethodInternal(DTypeDesc caller, string methodName, object classNameOrObject, ICollection args)
		{
			PhpException.Throw(PhpError.Notice, LibResources.GetString("call_user_method_deprecated"));

			object ret_val = false;
			DObject obj;
			string class_name;

			ScriptContext context = ScriptContext.CurrentContext;

            //DTypeDesc classContext = PhpStackTrace.GetClassContext();  // TODO: GetClassContext only if needed by context.ResolveType
            if (caller != null && caller.IsUnknown) caller = PhpStackTrace.GetClassContext();

			if ((obj = classNameOrObject as DObject) != null)
			{
				// push arguments on stack
				context.Stack.AddFrame(args);
				ret_val = obj.InvokeMethod(methodName, caller, context);
			}
			else if ((class_name = PhpVariable.AsString(classNameOrObject)) != null)
			{
				// push arguments on stack
				context.Stack.AddFrame(args);
				
				ResolveTypeFlags flags = ResolveTypeFlags.UseAutoload | ResolveTypeFlags.ThrowErrors;
                DTypeDesc type = PHP.Core.Convert.ObjectToTypeDesc(class_name, flags, caller, context, null, null);

                ret_val = Operators.InvokeStaticMethod(type, methodName, null, caller, context);
			}
			else
			{
				PhpException.InvalidArgument("classNameOrObject", LibResources.GetString("arg:not_object_or_class_name"));
			}

			return PhpVariable.Dereference(ret_val);
		}

 public ReflectionException(ScriptContext context, DTypeDesc caller)
     : base(context, caller)
 {
 }

 public RecursiveDirectoryIterator(ScriptContext/*!*/context, DTypeDesc caller)
     : base(context, caller)
 {
 }

 public FilesystemIterator(ScriptContext/*!*/context, DTypeDesc caller)
     : base(context, caller)
 {
 }

 public SplFileInfo(ScriptContext/*!*/context, DTypeDesc caller)
     : base(context, caller)
 {
 }