From 9c414b5da5c4fa6aa3154224d4bbc2471d9731b2 Mon Sep 17 00:00:00 2001
From: Bob Nystrom <robert@stuffwithstuff.com>
Date: Wed, 25 Mar 2015 20:20:26 -0700
Subject: [PATCH] Get Meta working with foreign methods.

---
 builtin/meta.wren  |  4 +++-
 src/vm/wren_io.c   |  2 +-
 src/vm/wren_meta.c | 17 +++++++++++++++--
 src/vm/wren_meta.h |  4 ++++
 src/vm/wren_vm.c   | 26 +++++++++++++++++---------
 5 files changed, 40 insertions(+), 13 deletions(-)

diff --git a/builtin/meta.wren b/builtin/meta.wren
index 3db22bbf..800999f4 100644
--- a/builtin/meta.wren
+++ b/builtin/meta.wren
@@ -1 +1,3 @@
-class Meta {}
+class Meta {
+  foreign static eval(source)
+}
diff --git a/src/vm/wren_io.c b/src/vm/wren_io.c
index 7c363f69..ff079f02 100644
--- a/src/vm/wren_io.c
+++ b/src/vm/wren_io.c
@@ -148,7 +148,7 @@ void wrenLoadIOLibrary(WrenVM* vm)
 WrenForeignMethodFn wrenBindIOForeignMethod(WrenVM* vm, const char* className,
                                             const char* signature)
 {
-  ASSERT(strcmp(className, "IO") == 0, "Should only have IO class.");
+  if (strcmp(className, "IO") != 0) return NULL;
   
   if (strcmp(signature, "writeString_(_)") == 0) return ioWriteString;
   if (strcmp(signature, "clock") == 0) return ioClock;
diff --git a/src/vm/wren_meta.c b/src/vm/wren_meta.c
index c49dea8d..da340d6a 100644
--- a/src/vm/wren_meta.c
+++ b/src/vm/wren_meta.c
@@ -2,9 +2,13 @@
 
 #if WREN_USE_LIB_META
 
+#include <string.h>
+
 // This string literal is generated automatically from meta.wren. Do not edit.
 static const char* libSource =
-"class Meta {}\n";
+"class Meta {\n"
+"  foreign static eval(source)\n"
+"}\n";
 
 void metaEval(WrenVM* vm)
 {
@@ -16,7 +20,16 @@ void metaEval(WrenVM* vm)
 void wrenLoadMetaLibrary(WrenVM* vm)
 {
   wrenInterpret(vm, "", libSource);
-  wrenDefineStaticMethod(vm, "Meta", "eval(_)", metaEval);
+}
+
+WrenForeignMethodFn wrenBindMetaForeignMethod(WrenVM* vm,
+                                              const char* className,
+                                              const char* signature)
+{
+  if (strcmp(className, "Meta") != 0) return NULL;
+
+  if (strcmp(signature, "eval(_)") == 0) return metaEval;
+  return NULL;
 }
 
 #endif
diff --git a/src/vm/wren_meta.h b/src/vm/wren_meta.h
index 10d56700..104a99b3 100644
--- a/src/vm/wren_meta.h
+++ b/src/vm/wren_meta.h
@@ -9,6 +9,10 @@
 
 void wrenLoadMetaLibrary(WrenVM* vm);
 
+WrenForeignMethodFn wrenBindMetaForeignMethod(WrenVM* vm,
+                                              const char* className,
+                                              const char* signature);
+
 #endif
 
 #endif
diff --git a/src/vm/wren_vm.c b/src/vm/wren_vm.c
index 6ee770dc..1c21686d 100644
--- a/src/vm/wren_vm.c
+++ b/src/vm/wren_vm.c
@@ -60,15 +60,15 @@ WrenVM* wrenNewVM(WrenConfiguration* configuration)
     vm->heapScalePercent = 100 + configuration->heapGrowthPercent;
   }
 
-  ObjString* name = AS_STRING(CONST_STRING(vm, "main"));
+  ObjString* name = AS_STRING(CONST_STRING(vm, "core"));
   wrenPushRoot(vm, (Obj*)name);
 
-  // Implicitly create a "main" module for the REPL or entry script.
-  ObjModule* mainModule = wrenNewModule(vm, name);
-  wrenPushRoot(vm, (Obj*)mainModule);
+  // Implicitly create a "core" module for the built in libraries.
+  ObjModule* coreModule = wrenNewModule(vm, name);
+  wrenPushRoot(vm, (Obj*)coreModule);
 
   vm->modules = wrenNewMap(vm);
-  wrenMapSet(vm, vm->modules, NULL_VAL, OBJ_VAL(mainModule));
+  wrenMapSet(vm, vm->modules, NULL_VAL, OBJ_VAL(coreModule));
 
   wrenPopRoot(vm); // mainModule.
   wrenPopRoot(vm); // name.
@@ -295,10 +295,18 @@ static WrenForeignMethodFn findForeignMethod(WrenVM* vm,
   }
 
   // Otherwise, try the built-in libraries.
-  #if WREN_USE_LIB_IO
-  fn = wrenBindIOForeignMethod(vm, className, signature);
-  if (fn != NULL) return fn;
-  #endif
+  if (strcmp(moduleName, "core") == 0)
+  {
+    #if WREN_USE_LIB_IO
+    fn = wrenBindIOForeignMethod(vm, className, signature);
+    if (fn != NULL) return fn;
+    #endif
+
+    #if WREN_USE_LIB_META
+    fn = wrenBindMetaForeignMethod(vm, className, signature);
+    if (fn != NULL) return fn;
+    #endif
+  }
 
   // TODO: Report a runtime error on failure to find it.
   return NULL;