Tab-completion in REPL based on module variables.

src/optional/wren_opt_meta.c

@@ -36,6 +36,34 @@ void metaCompile(WrenVM* vm)
   }
 }
 
+void metaGetModuleVariables(WrenVM* vm) {
+  wrenEnsureSlots(vm, 3);
+  
+  Value moduleValue = wrenMapGet(vm->modules, vm->apiStack[1]);
+  if (IS_UNDEFINED(moduleValue))
+  {
+    vm->apiStack[0] = NULL_VAL;
+    return;
+  }
+    
+  ObjModule* module = AS_MODULE(moduleValue);  
+  ObjList* names = wrenNewList(vm, module->variableNames.count);
+  vm->apiStack[0] = OBJ_VAL(names);
+
+  // Initialize the elements to null in case a collection happens when we
+  // allocate the strings below.
+  for (int i = 0; i < names->elements.count; i++)
+  {
+    names->elements.data[i] = NULL_VAL;
+  }
+  
+  for (int i = 0; i < names->elements.count; i++)
+  {
+    String* name = &module->variableNames.data[i];
+    names->elements.data[i] = wrenNewString(vm, name->buffer, name->length);
+  }
+}
+
 const char* wrenMetaSource()
 {
   return metaModuleSource;
@@ -49,9 +77,19 @@ WrenForeignMethodFn wrenMetaBindForeignMethod(WrenVM* vm,
   // There is only one foreign method in the meta module.
   ASSERT(strcmp(className, "Meta") == 0, "Should be in Meta class.");
   ASSERT(isStatic, "Should be static.");
-  ASSERT(strcmp(signature, "compile_(_,_,_)") == 0, "Should be compile method.");
   
-  return metaCompile;
+  if (strcmp(signature, "compile_(_,_,_)") == 0)
+  {
+    return metaCompile;
+  }
+  
+  if (strcmp(signature, "getModuleVariables_(_)") == 0)
+  {
+    return metaGetModuleVariables;
+  }
+  
+  ASSERT(false, "Unknown method.");
+  return NULL;
 }
 
 #endif

src/optional/wren_opt_meta.wren

@@ -1,4 +1,12 @@
 class Meta {
+  static getModuleVariables(module) {
+    if (!(module is String)) Fiber.abort("Module name must be a string.")
+    var result = getModuleVariables_(module)
+    if (result != null) return result
+
+    Fiber.abort("Could not find a module named '%(module)'.")
+  }
+
   static eval(source) {
     if (!(source is String)) Fiber.abort("Source code must be a string.")
 
@@ -15,4 +23,5 @@ class Meta {
   }
 
   foreign static compile_(source, isExpression, printErrors)
+  foreign static getModuleVariables_(module)
 }

src/optional/wren_opt_meta.wren.inc

@@ -1,6 +1,14 @@
 // Generated automatically from src/optional/wren_opt_meta.wren. Do not edit.
 static const char* metaModuleSource =
 "class Meta {\n"
+"  static getModuleVariables(module) {\n"
+"    if (!(module is String)) Fiber.abort(\"Module name must be a string.\")\n"
+"    var result = getModuleVariables_(module)\n"
+"    if (result != null) return result\n"
+"\n"
+"    Fiber.abort(\"Could not find a module named '%(module)'.\")\n"
+"  }\n"
+"\n"
 "  static eval(source) {\n"
 "    if (!(source is String)) Fiber.abort(\"Source code must be a string.\")\n"
 "\n"
@@ -17,4 +25,5 @@ static const char* metaModuleSource =
 "  }\n"
 "\n"
 "  foreign static compile_(source, isExpression, printErrors)\n"
+"  foreign static getModuleVariables_(module)\n"
 "}\n";