feat: add scheduler module and refactor built-in module loading into shared modules.c

Introduce a new scheduler module with fiber-based cooperative multitasking, including native bindings for resume operations and a Wren class for scheduling callables. Refactor the existing timer module and CLI code to use a centralized built-in module registry in modules.c, replacing direct includes of timer.h and timer.wren.inc. Update Xcode project and Makefile to compile the new scheduler.c, modules.c, and their generated .wren.inc sources.

src/cli/io.c

@@ -3,8 +3,7 @@
 #include <string.h>
 
 #include "io.h"
-
-#include "timer.h"
+#include "modules.h"
 
 char const* rootDirectory = NULL;
 
@@ -73,7 +72,8 @@ char* wrenFilePath(const char* name)
 
 char* readModule(WrenVM* vm, const char* module)
 {
-  if (strcmp(module, "timer") == 0) return timerGetSource();
+  char* source = readBuiltInModule(module);
+  if (source != NULL) return source;
   
   // First try to load the module with a ".wren" extension.
   char* modulePath = wrenFilePath(module);

src/cli/modules.c

@@ -0,0 +1,83 @@
+#include <stdlib.h>
+#include <string.h>
+
+#include "modules.h"
+
+#include "scheduler.wren.inc"
+#include "timer.wren.inc"
+
+#include "scheduler.h"
+#include "timer.h"
+
+typedef struct
+{
+  // The name of the module.
+  const char* name;
+  
+  // Pointer to the string containing the source code of the module. We use a
+  // pointer here because the string variable itself is not a constant
+  // expression so can't be used in the initializer below.
+  const char **source;
+
+  // The function that binds foreign methods in this module.
+  WrenForeignMethodFn (*bindMethodFn)(WrenVM* vm, const char* className,
+                                      bool isStatic, const char* signature);
+
+  // The function that binds foreign classes in this module.
+  WrenForeignClassMethods (*bindClassFn)(WrenVM* vm, const char* className);
+} BuiltInModule;
+
+// The array of built-in modules.
+static BuiltInModule modules[] =
+{
+  {"scheduler", &schedulerModuleSource, schedulerBindForeign, NULL},
+  {"timer",     &timerModuleSource, timerBindForeign, NULL},
+  
+  // Sentinel marking the end of the list.
+  {NULL, NULL, NULL, NULL}
+};
+
+// Looks for a built-in module with [name].
+//
+// Returns the BuildInModule for it or NULL if not found.
+static BuiltInModule* findModule(const char* name)
+{
+  for (int i = 0; modules[i].name != NULL; i++)
+  {
+    if (strcmp(name, modules[i].name) == 0) return &modules[i];
+  }
+  
+  return NULL;
+}
+
+char* readBuiltInModule(const char* name)
+{
+  BuiltInModule* module = findModule(name);
+  if (module == NULL) return NULL;
+  
+  size_t length = strlen(*module->source);
+  char* copy = (char*)malloc(length + 1);
+  strncpy(copy, *module->source, length + 1);
+  return copy;
+}
+
+WrenForeignMethodFn bindBuiltInForeignMethod(
+    WrenVM* vm, const char* moduleName, const char* className, bool isStatic,
+    const char* signature)
+{
+  BuiltInModule* module = findModule(moduleName);
+  if (module == NULL) return NULL;
+  
+  return module->bindMethodFn(vm, className, isStatic, signature);
+}
+
+WrenForeignClassMethods bindBuiltInForeignClass(
+    WrenVM* vm, const char* moduleName, const char* className)
+{
+  WrenForeignClassMethods methods = { NULL, NULL };
+  
+  BuiltInModule* module = findModule(moduleName);
+  if (module == NULL) return methods;
+
+  return module->bindClassFn(vm, className);
+}

src/cli/modules.h

@@ -0,0 +1,19 @@
+#ifndef modules_h
+#define modules_h
+
+#include "wren.h"
+
+char* readBuiltInModule(const char* module);
+
+// Looks up a foreign method in a built-in module.
+//
+// Returns `NULL` if [moduleName] is not a built-in module.
+WrenForeignMethodFn bindBuiltInForeignMethod(
+    WrenVM* vm, const char* moduleName, const char* className, bool isStatic,
+    const char* signature);
+
+// Binds foreign classes declared in a built-in modules.
+WrenForeignClassMethods bindBuiltInForeignClass(
+    WrenVM* vm, const char* moduleName, const char* className);
+
+#endif

src/cli/vm.c

@@ -2,8 +2,9 @@
 #include <string.h>
 
 #include "io.h"
+#include "modules.h"
 #include "vm.h"
-#include "timer.h"
+#include "scheduler.h"
 
 #define MAX_LINE_LENGTH 1024 // TODO: Something less arbitrary.
 
@@ -15,16 +16,15 @@ static WrenBindForeignClassFn bindClassFn = NULL;
 
 uv_loop_t* loop;
 
-/// Binds foreign methods declared in either built in modules, or the injected
-/// API test modules.
+// Binds foreign methods declared in either built in modules, or the injected
+// API test modules.
 static WrenForeignMethodFn bindForeignMethod(WrenVM* vm, const char* module,
     const char* className, bool isStatic, const char* signature)
 {
-  if (strcmp(module, "timer") == 0)
-  {
-    return timerBindForeign(vm, className, isStatic, signature);
-  }
-
+  WrenForeignMethodFn method = bindBuiltInForeignMethod(vm, module, className,
+                                                        isStatic, signature);
+  if (method != NULL) return method;
+  
   if (bindMethodFn != NULL)
   {
     return bindMethodFn(vm, module, className, isStatic, signature);
@@ -33,14 +33,14 @@ static WrenForeignMethodFn bindForeignMethod(WrenVM* vm, const char* module,
   return NULL;
 }
 
-/// Binds foreign classes declared in either built in modules, or the injected
-/// API test modules.
+// Binds foreign classes declared in either built in modules, or the injected
+// API test modules.
 static WrenForeignClassMethods bindForeignClass(
     WrenVM* vm, const char* module, const char* className)
 {
-  WrenForeignClassMethods methods = { NULL, NULL };
-
-  // TODO: Bind classes for built-in modules here.
+  WrenForeignClassMethods methods = bindBuiltInForeignClass(vm, module,
+                                                            className);
+  if (methods.allocate != NULL) return methods;
 
   if (bindClassFn != NULL)
   {
@@ -70,7 +70,7 @@ static void initVM()
 
 static void freeVM()
 {
-  timerReleaseMethods();
+  schedulerReleaseMethods();
 
   uv_loop_close(loop);
   free(loop);