First working machine

machine.hpp

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+/*
+ * SPDX-FileCopyrightText: Dora "cat" <cat@thenight.club>
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public License,
+ * v. 2.0. If a copy of the MPL was not distributed with this file, You can
+ * obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#ifndef GUARD_VARIADICMACHINE_MACHINE_H
+#define GUARD_VARIADICMACHINE_MACHINE_H
+
+#include <array>
+#include <cstdarg>
+#include <cstddef>
+#include <cstdint>
+#include <exception>
+#include <iostream>
+
+namespace VariadicMachine {
+enum Command : int16_t {
+  // Single Argument
+  NoCommand,
+  MoveLeft,
+  MoveRight,
+  Increment,
+  Decrement,
+  PrintAsCharacter,
+
+  // Two Arguments
+  IncrementBy,
+  DecrementBy
+};
+
+template <std::size_t maxCells = 2048> class VMachine {
+public:
+  template <typename... Commands> constexpr void Do(Commands &&...commands) {
+    (Execute(commands), ...);
+  }
+
+private:
+  Command State = Command::NoCommand;
+  std::array<std::int16_t, maxCells> memory;
+  std::int16_t W = 0, X = 0, Y = 0, Z = 0;
+  std::size_t maxCellLimit = maxCells, currentPosition = 0;
+
+  void Execute(int16_t command) {
+    switch (State) {
+    case Command::IncrementBy:
+      memory[currentPosition] += command;
+      State = Command::NoCommand;
+      return;
+
+    case Command::DecrementBy:
+      memory[currentPosition] -= command;
+      State = Command::NoCommand;
+      return;
+
+    default:
+      std::terminate();
+      break;
+
+    case Command::NoCommand:
+      break;
+    }
+
+    // State: NoCommand
+    switch (command) {
+    case Command::MoveLeft:
+      --currentPosition;
+      return;
+    case Command::MoveRight:
+      ++currentPosition;
+      return;
+
+    case Command::Increment:
+      ++memory[currentPosition];
+      return;
+    case Command::Decrement:
+      --memory[currentPosition];
+      return;
+
+    case Command::PrintAsCharacter:
+      std::wcout << static_cast<wchar_t>(memory[currentPosition]);
+      return;
+
+    // Double Argument Commands
+    case Command::IncrementBy:
+    case Command::DecrementBy:
+      State = static_cast<Command>(command);
+      return;
+
+    default:
+      std::cout << "Here\n";
+      std::terminate();
+      return;
+    }
+  }
+};
+} // namespace VariadicMachine
+#endif