Add repl server skeleton

README.md

@@ -85,16 +85,22 @@ Install [Geiser](https://www.nongnu.org/geiser/) then add the following to your
 
 The Emacs extension automatically recognize Scheme files inside Godot project directories as `Godot s7 Scheme` files.
 
-### Connecting
+### Connecting to the editor
 
-1. Add a `SchemeReplServer` to your scene (preferably as a child of a `Scheme` node) and set its `Auto Start` property to `true`.
+1. Start Godot with `--s7-tcp-port=<port-number>` (and/or `--s7-tcp-address=<bind-address>`).
 2. Check the port number in the Godot output window.
-3. `M-x connect-to-godot-s7`
+3. In Emacs, `M-x connect-to-godot-s7`
+
+### Connecting to a running scene
+
+1. In Godot, select `Debug / Customize Run Instances... / Main Run Args`
+   - Add `--s7-tcp-port=<port-number>` and/or `--s7-tcp-address=<bind-address>`.
+2. Steps 2 and 3 as above.
 
 ## Roadmap
 
 - [x] use Godot API from Scheme
-- [o] live coding interface via Emacs (wip)
+- [x] live coding interface via Emacs
 - [ ] expose tree-sitter API to Scheme
 - [ ] Scheme editor with syntax highlighting
 - [ ] Scheme notebooks

src/register_types.cpp

@@ -1,9 +1,11 @@
 #include "register_types.h"
 #include "scheme.hpp"
 #include "scheme_object.hpp"
+#include "scheme_repl_server.hpp"
 #include "scheme_script.hpp"
 #include "scheme_script_loader.hpp"
 #include <gdextension_interface.h>
+#include <godot_cpp/classes/engine.hpp>
 #include <godot_cpp/classes/resource_loader.hpp>
 #include <godot_cpp/core/class_db.hpp>
 #include <godot_cpp/core/defs.hpp>
@@ -13,10 +15,7 @@ using namespace godot;
 
 static Ref<SchemeScriptLoader> script_loader;
 
-void initialize_gdextension_types(ModuleInitializationLevel p_level) {
-  if (p_level != MODULE_INITIALIZATION_LEVEL_SCENE) {
-    return;
-  }
+void initialize_scene_types() {
   GDREGISTER_CLASS(SchemeScript);
   GDREGISTER_CLASS(SchemeScriptLoader);
   GDREGISTER_CLASS(Scheme);
@@ -26,15 +25,50 @@ void initialize_gdextension_types(ModuleInitializationLevel p_level) {
   ResourceLoader::get_singleton()->add_resource_format_loader(script_loader);
 }
 
-void uninitialize_gdextension_types(ModuleInitializationLevel p_level) {
-  if (p_level != MODULE_INITIALIZATION_LEVEL_SCENE) {
-    return;
-  }
-
+void uninitialize_scene_types() {
   ResourceLoader::get_singleton()->remove_resource_format_loader(script_loader);
   script_loader.unref();
 }
 
+static SchemeReplServer *repl_server;
+
+void initialize_server_types() {
+  GDREGISTER_CLASS(SchemeReplServer);
+  repl_server = memnew(SchemeReplServer);
+  repl_server->init();
+}
+
+void uninitialize_server_types() {
+  repl_server->finish();
+  memdelete(repl_server);
+}
+
+void initialize_gdextension_types(ModuleInitializationLevel p_level) {
+  switch (p_level) {
+    case MODULE_INITIALIZATION_LEVEL_SCENE:
+      initialize_scene_types();
+      break;
+    case MODULE_INITIALIZATION_LEVEL_EDITOR:
+      initialize_server_types();
+      break;
+    default:
+      break;
+  }
+}
+
+void uninitialize_gdextension_types(ModuleInitializationLevel p_level) {
+  switch (p_level) {
+    case MODULE_INITIALIZATION_LEVEL_SCENE:
+      uninitialize_scene_types();
+      break;
+    case MODULE_INITIALIZATION_LEVEL_EDITOR:
+      uninitialize_server_types();
+      break;
+    default:
+      break;
+  }
+}
+
 extern "C" {
 GDExtensionBool GDE_EXPORT godot_s7_scheme_library_init(
     GDExtensionInterfaceGetProcAddress p_get_proc_address,
@@ -43,7 +77,7 @@ GDExtensionBool GDE_EXPORT godot_s7_scheme_library_init(
   GDExtensionBinding::InitObject init_obj(p_get_proc_address, p_library, r_initialization);
   init_obj.register_initializer(initialize_gdextension_types);
   init_obj.register_terminator(uninitialize_gdextension_types);
-  init_obj.set_minimum_library_initialization_level(MODULE_INITIALIZATION_LEVEL_SCENE);
+  init_obj.set_minimum_library_initialization_level(MODULE_INITIALIZATION_LEVEL_EDITOR);
 
   return init_obj.init();
 }

src/scheme_repl_server.cpp

@@ -0,0 +1,63 @@
+#include "scheme_repl_server.hpp"
+#include <godot_cpp/classes/engine.hpp>
+#include <godot_cpp/classes/os.hpp>
+#include <godot_cpp/classes/stream_peer_tcp.hpp>
+#include <godot_cpp/variant/utility_functions.hpp>
+
+using namespace godot;
+using gd = godot::UtilityFunctions;
+
+void SchemeReplServer::_bind_methods() {
+  ClassDB::bind_method(D_METHOD("server_loop"), &SchemeReplServer::server_loop);
+}
+
+void SchemeReplServer::server_loop() {
+  // TODO: only start server when --s7-tcp-port=<number> and/or --s7-tcp-address=<address> are present in OS::get_cmdline_args()
+
+  String tcp_bind_address = "127.0.0.1";
+  int tcp_port = 0;
+
+  Ref<TCPServer> tcp_server;
+  tcp_server.instantiate();
+
+  auto error = tcp_server->listen(tcp_port, tcp_bind_address);
+  ERR_FAIL_COND_MSG(error != OK, ("Failed to start scheme repl server: " + UtilityFunctions::error_string(error)));
+
+  uint64_t msdelay = 250;
+
+  while (!exit_thread) {
+    // TODO: accept client connections
+    // TODO: handle pending data
+    OS::get_singleton()->delay_msec(msdelay);
+  }
+
+  tcp_server->stop();
+}
+
+Error SchemeReplServer::init() {
+  ERR_FAIL_COND_V_MSG(thread.is_valid(), ERR_BUG, "Scheme repl server can only be started once!");
+  exit_thread = false;
+  thread.instantiate();
+  return thread->start(Callable::create(this, "server_loop"), Thread::PRIORITY_LOW);
+}
+
+void SchemeReplServer::finish() {
+  if (thread.is_null()) {
+    return;
+  }
+
+  exit_thread = true;
+  thread->wait_to_finish();
+
+  thread.unref();
+}
+
+SchemeReplServer *SchemeReplServer::singleton = NULL;
+
+SchemeReplServer *SchemeReplServer::get_singleton() {
+  return singleton;
+}
+
+SchemeReplServer::SchemeReplServer() {
+  singleton = this;
+}

src/scheme_repl_server.hpp

@@ -0,0 +1,32 @@
+#ifndef GODOT_S7_SCHEME_SCHEME_REPL_SERVER_H
+#define GODOT_S7_SCHEME_SCHEME_REPL_SERVER_H
+
+#include "s7.hpp"
+#include <godot_cpp/classes/object.hpp>
+#include <godot_cpp/classes/stream_peer_tcp.hpp>
+#include <godot_cpp/classes/tcp_server.hpp>
+#include <godot_cpp/classes/thread.hpp>
+
+namespace godot {
+
+class SchemeReplServer : public Object {
+  GDCLASS(SchemeReplServer, Object);
+
+  static SchemeReplServer *singleton;
+
+private:
+  mutable bool exit_thread;
+  Ref<Thread> thread;
+
+public:
+  static SchemeReplServer *get_singleton();
+  SchemeReplServer();
+  Error init();
+  void finish();
+
+protected:
+  static void _bind_methods();
+  void server_loop();
+};
+} //namespace godot
+#endif //GODOT_S7_SCHEME_SCHEME_REPL_SERVER_H