diff --git a/luprex/core/cpp/source.cpp b/luprex/core/cpp/source.cpp
index 3436c5b2..9d1c730d 100644
--- a/luprex/core/cpp/source.cpp
+++ b/luprex/core/cpp/source.cpp
@@ -77,6 +77,7 @@ static void source_install_builtins(lua_State *L) {
     load_builtin_class(L, "string", luaopen_string);
     load_builtin_class(L, "math", luaopen_math);
     load_builtin_class(L, "debug", luaopen_debug);
+    load_builtin_class(L, "coroutine", luaopen_coroutine);
 
     // Nuke a few of the builtin functions for sandboxing reasons.
     LS.getglobaltable(globtab);
@@ -352,3 +353,21 @@ void SourceDB::init(lua_State *L) {
     }
 }
 
+// These should go away eventually.  They're for debugging.
+LuaDefine(coroutine_setnextid, "c") {
+    LuaArg co, lid;
+    LuaStack LS(L, co, lid);
+    lua_State *CO = LS.ckthread(co);
+    lua_Number id = LS.ckinteger(lid);
+    lua_setnextid(CO, id);
+    return LS.result();
+}
+
+LuaDefine(coroutine_getnextid, "c") {
+    LuaArg co;
+    LuaRet lid;
+    LuaStack LS(L, co, lid);
+    lua_State *CO = LS.ckthread(co);
+    LS.set(lid, lua_getnextid(CO));
+    return LS.result();
+}