Wren testing

wren/vm/wren_core.h

@@ -0,0 +1,23 @@
+#ifndef wren_core_h
+#define wren_core_h
+
+#include "wren_vm.h"
+
+// This module defines the built-in classes and their primitives methods that
+// are implemented directly in C code. Some languages try to implement as much
+// of the core module itself in the primary language instead of in the host
+// language.
+//
+// With Wren, we try to do as much of it in C as possible. Primitive methods
+// are always faster than code written in Wren, and it minimizes startup time
+// since we don't have to parse, compile, and execute Wren code.
+//
+// There is one limitation, though. Methods written in C cannot call Wren ones.
+// They can only be the top of the callstack, and immediately return. This
+// makes it difficult to have primitive methods that rely on polymorphic
+// behavior. For example, `System.print` should call `toString` on its argument,
+// including user-defined `toString` methods on user-defined classes.
+
+void wrenInitializeCore(WrenVM* vm);
+
+#endif