Hi Nakadaira-san,

> if_lua_5.2_udata.diff causes crash.
> 
> :let x = {"n": 123}
> :lua x = vim.eval("x")
> :unlet x
> 
> ... do something to waste memory
> :for i in range(999999) | let z = {"n": 999} | endfor
> 
> :lua print(x.n)   <- Vim's x is already freed
> crash...

Thanks for the report! I'm attaching a patch that should fix it; can you
please try it?

I had to change eval.c and proto/if_lua.pro to notify Lua whenever a list and
dict are freed: lists and dicts are now not different from buffer and window
objects. I also had to add validity checks for all functions on these objects
-- I think Muraoka also had similar checks in his previous patch and I forgot
to add them.

Cheers,
Luis

-- 
Computers are useless. They can only give you answers.
                -- Pablo Picasso

-- 
Luis Carvalho (Kozure)
lua -e 'print((("[email protected]"):gsub("(%u+%.)","")))'

-- 
You received this message from the "vim_dev" maillist.
Do not top-post! Type your reply below the text you are replying to.
For more information, visit http://www.vim.org/maillist.php
diff -Naur src.orig/eval.c src/eval.c
--- src.orig/eval.c	2012-01-12 12:14:29.015873654 -0500
+++ src/eval.c	2012-01-12 10:57:48.539950133 -0500
@@ -5916,6 +5916,9 @@
 	    clear_tv(&item->li_tv);
 	vim_free(item);
     }
+#ifdef FEAT_LUA
+    lua_list_free(l);
+#endif
     vim_free(l);
 }
 
@@ -6954,6 +6957,9 @@
 	}
     }
     hash_clear(&d->dv_hashtab);
+#ifdef FEAT_LUA
+    lua_dict_free(d);
+#endif
     vim_free(d);
 }
 
diff -Naur src.orig/if_lua.c src/if_lua.c
--- src.orig/if_lua.c	2012-01-12 12:14:10.911873955 -0500
+++ src/if_lua.c	2012-01-12 12:06:44.119881383 -0500
@@ -1,4 +1,4 @@
-/* vi:set ts=8 sts=4 sw=4:
+/* vi:set ts=8 sts=4 sw=4 noet:
  *
  * VIM - Vi IMproved	by Bram Moolenaar
  *
@@ -24,12 +24,26 @@
 
 typedef buf_T *luaV_Buffer;
 typedef win_T *luaV_Window;
+typedef dict_T *luaV_Dict;
+typedef list_T *luaV_List;
 typedef void (*msgfunc_T)(char_u *);
 
+static const char LUAVIM_DICT[] = "dict";
+static const char LUAVIM_LIST[] = "list";
 static const char LUAVIM_BUFFER[] = "buffer";
 static const char LUAVIM_WINDOW[] = "window";
 static const char LUAVIM_FREE[] = "luaV_free";
 
+/* most functions are closures with a cache table as first upvalue;
+ * get/setudata manage references to vim userdata in cache table through
+ * object pointers (light userdata) */
+#define luaV_getudata(L, v) \
+    lua_pushlightuserdata((L), (void *) (v)); \
+    lua_rawget((L), lua_upvalueindex(1))
+#define luaV_setudata(L, v) \
+    lua_pushlightuserdata((L), (void *) (v)); \
+    lua_pushvalue((L), -2); \
+    lua_rawset((L), lua_upvalueindex(1))
 #define luaV_getfield(L, s) \
     lua_pushlightuserdata((L), (void *)(s)); \
     lua_rawget((L), LUA_REGISTRYINDEX)
@@ -38,6 +52,15 @@
 #define luaV_msg(L) luaV_msgfunc((L), (msgfunc_T) msg)
 #define luaV_emsg(L) luaV_msgfunc((L), (msgfunc_T) emsg)
 
+static luaV_List *luaV_pushlist (lua_State *L, list_T *lis);
+static luaV_Dict *luaV_pushdict (lua_State *L, dict_T *dic);
+
+#if LUA_VERSION_NUM <= 501
+#define luaV_openlib(L, l, n) luaL_openlib(L, NULL, l, n)
+#define luaL_typeerror luaL_typerror
+#else
+#define luaV_openlib luaL_setfuncs
+#endif
 
 #ifdef DYNAMIC_LUA
 
@@ -54,32 +77,54 @@
 #endif
 
 /* lauxlib */
+#if LUA_VERSION_NUM <= 501
 #define luaL_register dll_luaL_register
+#define luaL_prepbuffer dll_luaL_prepbuffer
+#define luaL_openlib dll_luaL_openlib
 #define luaL_typerror dll_luaL_typerror
+#define luaL_loadfile dll_luaL_loadfile
+#define luaL_loadbuffer dll_luaL_loadbuffer
+#else
+#define luaL_prepbuffsize dll_luaL_prepbuffsize
+#define luaL_setfuncs dll_luaL_setfuncs
+#define luaL_loadfilex dll_luaL_loadfilex
+#define luaL_loadbufferx dll_luaL_loadbufferx
+#define luaL_argerror dll_luaL_argerror
+#endif
 #define luaL_checklstring dll_luaL_checklstring
 #define luaL_checkinteger dll_luaL_checkinteger
 #define luaL_optinteger dll_luaL_optinteger
 #define luaL_checktype dll_luaL_checktype
 #define luaL_error dll_luaL_error
-#define luaL_loadfile dll_luaL_loadfile
-#define luaL_loadbuffer dll_luaL_loadbuffer
 #define luaL_newstate dll_luaL_newstate
 #define luaL_buffinit dll_luaL_buffinit
-#define luaL_prepbuffer dll_luaL_prepbuffer
 #define luaL_addlstring dll_luaL_addlstring
 #define luaL_pushresult dll_luaL_pushresult
 /* lua */
+#if LUA_VERSION_NUM <= 501
+#define lua_tonumber dll_lua_tonumber
+#define lua_tointeger dll_lua_tointeger
+#define lua_call dll_lua_call
+#define lua_pcall dll_lua_pcall
+#else
+#define lua_tonumberx dll_lua_tonumberx
+#define lua_tointegerx dll_lua_tointegerx
+#define lua_callk dll_lua_callk
+#define lua_pcallk dll_lua_pcallk
+#define lua_getglobal dll_lua_getglobal
+#define lua_setglobal dll_lua_setglobal
+#define lua_typename dll_lua_typename
+#endif
 #define lua_close dll_lua_close
 #define lua_gettop dll_lua_gettop
 #define lua_settop dll_lua_settop
 #define lua_pushvalue dll_lua_pushvalue
 #define lua_replace dll_lua_replace
+#define lua_remove dll_lua_remove
 #define lua_isnumber dll_lua_isnumber
 #define lua_isstring dll_lua_isstring
 #define lua_type dll_lua_type
 #define lua_rawequal dll_lua_rawequal
-#define lua_tonumber dll_lua_tonumber
-#define lua_tointeger dll_lua_tointeger
 #define lua_toboolean dll_lua_toboolean
 #define lua_tolstring dll_lua_tolstring
 #define lua_touserdata dll_lua_touserdata
@@ -94,16 +139,14 @@
 #define lua_pushlightuserdata dll_lua_pushlightuserdata
 #define lua_getfield dll_lua_getfield
 #define lua_rawget dll_lua_rawget
+#define lua_rawgeti dll_lua_rawgeti
 #define lua_createtable dll_lua_createtable
 #define lua_newuserdata dll_lua_newuserdata
 #define lua_getmetatable dll_lua_getmetatable
 #define lua_setfield dll_lua_setfield
 #define lua_rawset dll_lua_rawset
 #define lua_rawseti dll_lua_rawseti
-#define lua_remove dll_lua_remove
 #define lua_setmetatable dll_lua_setmetatable
-#define lua_call dll_lua_call
-#define lua_pcall dll_lua_pcall
 /* libs */
 #define luaopen_base dll_luaopen_base
 #define luaopen_table dll_luaopen_table
@@ -116,32 +159,56 @@
 #define luaL_openlibs dll_luaL_openlibs
 
 /* lauxlib */
+#if LUA_VERSION_NUM <= 501
 void (*dll_luaL_register) (lua_State *L, const char *libname, const luaL_Reg *l);
+char *(*dll_luaL_prepbuffer) (luaL_Buffer *B);
+void (*dll_luaL_openlib) (lua_State *L, const char *libname, const luaL_Reg *l, int nup);
 int (*dll_luaL_typerror) (lua_State *L, int narg, const char *tname);
+int (*dll_luaL_loadfile) (lua_State *L, const char *filename);
+int (*dll_luaL_loadbuffer) (lua_State *L, const char *buff, size_t sz, const char *name);
+#else
+char *(*dll_luaL_prepbuffsize) (luaL_Buffer *B, size_t sz);
+void (*dll_luaL_setfuncs) (lua_State *L, const luaL_Reg *l, int nup);
+int (*dll_luaL_loadfilex) (lua_State *L, const char *filename, const char *mode);
+int (*dll_luaL_loadbufferx) (lua_State *L, const char *buff, size_t sz, const char *name, const char *mode);
+int (*dll_luaL_argerror) (lua_State *L, int numarg, const char *extramsg);
+#endif
 const char *(*dll_luaL_checklstring) (lua_State *L, int numArg, size_t *l);
 lua_Integer (*dll_luaL_checkinteger) (lua_State *L, int numArg);
 lua_Integer (*dll_luaL_optinteger) (lua_State *L, int nArg, lua_Integer def);
 void (*dll_luaL_checktype) (lua_State *L, int narg, int t);
 int (*dll_luaL_error) (lua_State *L, const char *fmt, ...);
-int (*dll_luaL_loadfile) (lua_State *L, const char *filename);
-int (*dll_luaL_loadbuffer) (lua_State *L, const char *buff, size_t sz, const char *name);
 lua_State *(*dll_luaL_newstate) (void);
 void (*dll_luaL_buffinit) (lua_State *L, luaL_Buffer *B);
-char *(*dll_luaL_prepbuffer) (luaL_Buffer *B);
 void (*dll_luaL_addlstring) (luaL_Buffer *B, const char *s, size_t l);
 void (*dll_luaL_pushresult) (luaL_Buffer *B);
 /* lua */
+#if LUA_VERSION_NUM <= 501
+lua_Number (*dll_lua_tonumber) (lua_State *L, int idx);
+lua_Integer (*dll_lua_tointeger) (lua_State *L, int idx);
+void (*dll_lua_call) (lua_State *L, int nargs, int nresults);
+int (*dll_lua_pcall) (lua_State *L, int nargs, int nresults, int errfunc);
+#else
+lua_Number (*dll_lua_tonumberx) (lua_State *L, int idx, int *isnum);
+lua_Integer (*dll_lua_tointegerx) (lua_State *L, int idx, int *isnum);
+void (*dll_lua_callk) (lua_State *L, int nargs, int nresults, int ctx,
+        lua_CFunction k);
+int (*dll_lua_pcallk) (lua_State *L, int nargs, int nresults, int errfunc,
+        int ctx, lua_CFunction k);
+void (*dll_lua_getglobal) (lua_State *L, const char *var);
+void (*dll_lua_setglobal) (lua_State *L, const char *var);
+const char *(*dll_lua_typename) (lua_State *L, int tp);
+#endif
 void       (*dll_lua_close) (lua_State *L);
 int (*dll_lua_gettop) (lua_State *L);
 void (*dll_lua_settop) (lua_State *L, int idx);
 void (*dll_lua_pushvalue) (lua_State *L, int idx);
 void (*dll_lua_replace) (lua_State *L, int idx);
+void (*dll_lua_remove) (lua_State *L, int idx);
 int (*dll_lua_isnumber) (lua_State *L, int idx);
 int (*dll_lua_isstring) (lua_State *L, int idx);
 int (*dll_lua_type) (lua_State *L, int idx);
 int (*dll_lua_rawequal) (lua_State *L, int idx1, int idx2);
-lua_Number (*dll_lua_tonumber) (lua_State *L, int idx);
-lua_Integer (*dll_lua_tointeger) (lua_State *L, int idx);
 int (*dll_lua_toboolean) (lua_State *L, int idx);
 const char *(*dll_lua_tolstring) (lua_State *L, int idx, size_t *len);
 void *(*dll_lua_touserdata) (lua_State *L, int idx);
@@ -156,16 +223,14 @@
 void (*dll_lua_pushlightuserdata) (lua_State *L, void *p);
 void (*dll_lua_getfield) (lua_State *L, int idx, const char *k);
 void (*dll_lua_rawget) (lua_State *L, int idx);
+void (*dll_lua_rawgeti) (lua_State *L, int idx, int n);
 void (*dll_lua_createtable) (lua_State *L, int narr, int nrec);
 void *(*dll_lua_newuserdata) (lua_State *L, size_t sz);
 int (*dll_lua_getmetatable) (lua_State *L, int objindex);
 void (*dll_lua_setfield) (lua_State *L, int idx, const char *k);
 void (*dll_lua_rawset) (lua_State *L, int idx);
 void (*dll_lua_rawseti) (lua_State *L, int idx, int n);
-void (*dll_lua_remove) (lua_State *L, int idx);
 int (*dll_lua_setmetatable) (lua_State *L, int objindex);
-void (*dll_lua_call) (lua_State *L, int nargs, int nresults);
-int (*dll_lua_pcall) (lua_State *L, int nargs, int nresults, int errfunc);
 /* libs */
 int (*dll_luaopen_base) (lua_State *L);
 int (*dll_luaopen_table) (lua_State *L);
@@ -185,32 +250,54 @@
 
 static const luaV_Reg luaV_dll[] = {
     /* lauxlib */
+#if LUA_VERSION_NUM <= 501
     {"luaL_register", (luaV_function) &dll_luaL_register},
+    {"luaL_prepbuffer", (luaV_function) &dll_luaL_prepbuffer},
+    {"luaL_openlib", (luaV_function) &dll_luaL_openlib},
     {"luaL_typerror", (luaV_function) &dll_luaL_typerror},
+    {"luaL_loadfile", (luaV_function) &dll_luaL_loadfile},
+    {"luaL_loadbuffer", (luaV_function) &dll_luaL_loadbuffer},
+#else
+    {"luaL_prepbuffsize", (luaV_function) &dll_luaL_prepbuffsize},
+    {"luaL_setfuncs", (luaV_function) &dll_luaL_setfuncs},
+    {"luaL_loadfilex", (luaV_function) &dll_luaL_loadfilex},
+    {"luaL_loadbufferx", (luaV_function) &dll_luaL_loadbufferx},
+    {"luaL_argerror", (luaV_function) &dll_luaL_argerror},
+#endif
     {"luaL_checklstring", (luaV_function) &dll_luaL_checklstring},
     {"luaL_checkinteger", (luaV_function) &dll_luaL_checkinteger},
     {"luaL_optinteger", (luaV_function) &dll_luaL_optinteger},
     {"luaL_checktype", (luaV_function) &dll_luaL_checktype},
     {"luaL_error", (luaV_function) &dll_luaL_error},
-    {"luaL_loadfile", (luaV_function) &dll_luaL_loadfile},
-    {"luaL_loadbuffer", (luaV_function) &dll_luaL_loadbuffer},
     {"luaL_newstate", (luaV_function) &dll_luaL_newstate},
     {"luaL_buffinit", (luaV_function) &dll_luaL_buffinit},
-    {"luaL_prepbuffer", (luaV_function) &dll_luaL_prepbuffer},
     {"luaL_addlstring", (luaV_function) &dll_luaL_addlstring},
     {"luaL_pushresult", (luaV_function) &dll_luaL_pushresult},
     /* lua */
+#if LUA_VERSION_NUM <= 501
+    {"lua_tonumber", (luaV_function) &dll_lua_tonumber},
+    {"lua_tointeger", (luaV_function) &dll_lua_tointeger},
+    {"lua_call", (luaV_function) &dll_lua_call},
+    {"lua_pcall", (luaV_function) &dll_lua_pcall},
+#else
+    {"lua_tonumberx", (luaV_function) &dll_lua_tonumberx},
+    {"lua_tointegerx", (luaV_function) &dll_lua_tointegerx},
+    {"lua_callk", (luaV_function) &dll_lua_callk},
+    {"lua_pcallk", (luaV_function) &dll_lua_pcallk},
+    {"lua_getglobal", (luaV_function) &dll_lua_getglobal},
+    {"lua_setglobal", (luaV_function) &dll_lua_setglobal},
+    {"lua_typename", (luaV_function) &dll_lua_typename},
+#endif
     {"lua_close", (luaV_function) &dll_lua_close},
     {"lua_gettop", (luaV_function) &dll_lua_gettop},
     {"lua_settop", (luaV_function) &dll_lua_settop},
     {"lua_pushvalue", (luaV_function) &dll_lua_pushvalue},
     {"lua_replace", (luaV_function) &dll_lua_replace},
+    {"lua_remove", (luaV_function) &dll_lua_remove},
     {"lua_isnumber", (luaV_function) &dll_lua_isnumber},
     {"lua_isstring", (luaV_function) &dll_lua_isstring},
     {"lua_type", (luaV_function) &dll_lua_type},
     {"lua_rawequal", (luaV_function) &dll_lua_rawequal},
-    {"lua_tonumber", (luaV_function) &dll_lua_tonumber},
-    {"lua_tointeger", (luaV_function) &dll_lua_tointeger},
     {"lua_toboolean", (luaV_function) &dll_lua_toboolean},
     {"lua_tolstring", (luaV_function) &dll_lua_tolstring},
     {"lua_touserdata", (luaV_function) &dll_lua_touserdata},
@@ -225,16 +312,14 @@
     {"lua_pushlightuserdata", (luaV_function) &dll_lua_pushlightuserdata},
     {"lua_getfield", (luaV_function) &dll_lua_getfield},
     {"lua_rawget", (luaV_function) &dll_lua_rawget},
+    {"lua_rawgeti", (luaV_function) &dll_lua_rawgeti},
     {"lua_createtable", (luaV_function) &dll_lua_createtable},
     {"lua_newuserdata", (luaV_function) &dll_lua_newuserdata},
     {"lua_getmetatable", (luaV_function) &dll_lua_getmetatable},
     {"lua_setfield", (luaV_function) &dll_lua_setfield},
     {"lua_rawset", (luaV_function) &dll_lua_rawset},
     {"lua_rawseti", (luaV_function) &dll_lua_rawseti},
-    {"lua_remove", (luaV_function) &dll_lua_remove},
     {"lua_setmetatable", (luaV_function) &dll_lua_setmetatable},
-    {"lua_call", (luaV_function) &dll_lua_call},
-    {"lua_pcall", (luaV_function) &dll_lua_pcall},
     /* libs */
     {"luaopen_base", (luaV_function) &dll_luaopen_base},
     {"luaopen_table", (luaV_function) &dll_luaopen_table},
@@ -294,6 +379,16 @@
 
 #endif /* DYNAMIC_LUA */
 
+#if LUA_VERSION_NUM > 501
+    static int
+luaL_typeerror (lua_State *L, int narg, const char *tname)
+{
+    const char *msg = lua_pushfstring(L, "%s expected, got %s",
+            tname, luaL_typename(L, narg));
+    return luaL_argerror(L, narg, msg);
+}
+#endif
+
 
 /* =======   Internal   ======= */
 
@@ -327,10 +422,22 @@
 }
 
     static void *
+luaV_checkcache(lua_State *L, void *p)
+{
+    luaV_getudata(L, p);
+    if (lua_isnil(L, -1)) luaL_error(L, "invalid object");
+    lua_pop(L, 1);
+    return p;
+}
+
+#define luaV_checkvalid(L,luatyp,ud) \
+    luaV_checkcache((L), (void *) *((luatyp *) lua_touserdata((L),ud)))
+
+    static void *
 luaV_checkudata(lua_State *L, int ud, const char *tname)
 {
     void *p = luaV_toudata(L, ud, tname);
-    if (p == NULL) luaL_typerror(L, ud, tname);
+    if (p == NULL) luaL_typeerror(L, ud, tname);
     return p;
 }
 
@@ -351,66 +458,12 @@
 	    lua_pushnumber(L, (lua_Number) tv->vval.v_float);
 	    break;
 #endif
-	case VAR_LIST: {
-	    list_T *l = tv->vval.v_list;
-
-	    if (l != NULL)
-	    {
-		/* check cache */
-		lua_pushlightuserdata(L, (void *) l);
-		lua_rawget(L, LUA_ENVIRONINDEX);
-		if (lua_isnil(L, -1)) /* not interned? */
-		{
-		    listitem_T *li;
-		    int n = 0;
-		    lua_pop(L, 1); /* nil */
-		    lua_newtable(L);
-		    lua_pushlightuserdata(L, (void *) l);
-		    lua_pushvalue(L, -2);
-		    lua_rawset(L, LUA_ENVIRONINDEX);
-		    for (li = l->lv_first; li != NULL; li = li->li_next)
-		    {
-			luaV_pushtypval(L, &li->li_tv);
-			lua_rawseti(L, -2, ++n);
-		    }
-		}
-	    }
-	    else lua_pushnil(L);
+	case VAR_LIST:
+	    luaV_pushlist(L, tv->vval.v_list);
 	    break;
-		       }
-	case VAR_DICT: {
-	    dict_T *d = tv->vval.v_dict;
-
-	    if (d != NULL)
-	    {
-		/* check cache */
-		lua_pushlightuserdata(L, (void *) d);
-		lua_rawget(L, LUA_ENVIRONINDEX);
-		if (lua_isnil(L, -1)) /* not interned? */
-		{
-		    hashtab_T *ht = &d->dv_hashtab;
-		    hashitem_T *hi;
-		    int n = ht->ht_used; /* remaining items */
-		    lua_pop(L, 1); /* nil */
-		    lua_newtable(L);
-		    lua_pushlightuserdata(L, (void *) d);
-		    lua_pushvalue(L, -2);
-		    lua_rawset(L, LUA_ENVIRONINDEX);
-		    for (hi = ht->ht_array; n > 0; hi++)
-		    {
-			if (!HASHITEM_EMPTY(hi))
-			{
-			    dictitem_T *di = dict_lookup(hi);
-			    luaV_pushtypval(L, &di->di_tv);
-			    lua_setfield(L, -2, (char *) hi->hi_key);
-			    n--;
-			}
-		    }
-		}
-	    }
-	    else lua_pushnil(L);
+	case VAR_DICT:
+	    luaV_pushdict(L, tv->vval.v_dict);
 	    break;
-	}
 	default:
 	    luaL_error(L, "invalid type");
     }
@@ -481,89 +534,214 @@
     lua_pop(L, 2); /* original and modified strings */
 }
 
+#define luaV_newtype(typ,tname,luatyp,luatname) \
+	static luatyp * \
+    luaV_new##tname (lua_State *L, typ *obj) \
+    { \
+	luatyp *o = (luatyp *) lua_newuserdata(L, sizeof(luatyp)); \
+	*o = obj; \
+	luaV_setudata(L, obj); /* cache[lis] = udata */ \
+	luaV_getfield(L, luatname); \
+	lua_setmetatable(L, -2); \
+	return o; \
+    } \
+    \
+	static luatyp * \
+    luaV_push##tname (lua_State *L, typ *obj) \
+    { \
+	luatyp *o = NULL; \
+	if (obj == NULL) \
+	    lua_pushnil(L); \
+	else { \
+	    luaV_getudata(L, obj); \
+	    if (lua_isnil(L, -1)) /* not interned? */ \
+	    { \
+		lua_pop(L, 1); \
+		o = luaV_new##tname(L, obj); \
+	    } \
+	    else \
+		o = (luatyp *) lua_touserdata(L, -1); \
+	} \
+	return o; \
+    } \
+    \
+	static int \
+    luaV_##tname##_tostring (lua_State *L) \
+    { \
+	lua_pushfstring(L, "%s: %p", luatname, lua_touserdata(L, 1)); \
+	return 1; \
+    }
+
+luaV_newtype(list_T, list, luaV_List, LUAVIM_LIST)
+luaV_newtype(dict_T, dict, luaV_Dict, LUAVIM_DICT)
+luaV_newtype(buf_T, buffer, luaV_Buffer, LUAVIM_BUFFER)
+luaV_newtype(win_T, window, luaV_Window, LUAVIM_WINDOW)
 
-/* =======   Buffer type   ======= */
+/* =======   List type   ======= */
 
-    static luaV_Buffer *
-luaV_newbuffer(lua_State *L, buf_T *buf)
+    static int
+luaV_list_len (lua_State *L)
 {
-    luaV_Buffer *b = (luaV_Buffer *) lua_newuserdata(L, sizeof(luaV_Buffer));
-    *b = buf;
-    lua_pushlightuserdata(L, (void *) buf);
-    lua_pushvalue(L, -2);
-    lua_rawset(L, LUA_ENVIRONINDEX); /* env[buf] = udata */
-    /* to avoid GC, store as key in env */
-    lua_pushvalue(L, -1);
-    lua_pushboolean(L, 1);
-    lua_rawset(L, LUA_ENVIRONINDEX); /* env[udata] = true */
-    /* set metatable */
-    luaV_getfield(L, LUAVIM_BUFFER);
-    lua_setmetatable(L, -2);
-    return b;
+    list_T *l = (list_T *) luaV_checkvalid(L, luaV_List, 1);
+    lua_pushinteger(L, (l == NULL) ? 0 : (int) l->lv_len);
+    return 1;
+}
+
+    static int
+luaV_list_iter (lua_State *L)
+{
+    listitem_T *li = (listitem_T *) lua_touserdata(L, lua_upvalueindex(2));
+    if (li == NULL) return 0;
+    luaV_pushtypval(L, &li->li_tv);
+    lua_pushlightuserdata(L, (void *) li->li_next);
+    lua_replace(L, lua_upvalueindex(2));
+    return 1;
 }
 
-    static luaV_Buffer *
-luaV_pushbuffer (lua_State *L, buf_T *buf)
+    static int
+luaV_list_call (lua_State *L)
+{
+    list_T *l = (list_T *) luaV_checkvalid(L, luaV_List, 1);
+    lua_pushvalue(L, lua_upvalueindex(1)); /* pass cache table along */
+    lua_pushlightuserdata(L, (void *) l->lv_first);
+    lua_pushcclosure(L, luaV_list_iter, 2);
+    return 1;
+}
+
+    static listitem_T *
+list_find (list_T *l, long n)
 {
-    luaV_Buffer *b = NULL;
-    if (buf == NULL)
+    listitem_T *li;
+    if (l == NULL || n < -l->lv_len || n >= l->lv_len)
+	return NULL;
+    if (n < 0) /* search backward? */
+	for (li = l->lv_last; n < -1; li = li->li_prev)
+	    n++;
+    else /* search forward */
+	for (li = l->lv_first; n > 0; li = li->li_next)
+	    n--;
+    return li;
+}
+
+    static int
+luaV_list_index (lua_State *L)
+{
+    list_T *l = (list_T *) luaV_checkvalid(L, luaV_List, 1);
+    long n = (long) luaL_checkinteger(L, 2);
+    listitem_T *li = list_find(l, n);
+    if (li == NULL)
 	lua_pushnil(L);
-    else {
-	lua_pushlightuserdata(L, (void *) buf);
-	lua_rawget(L, LUA_ENVIRONINDEX);
-	if (lua_isnil(L, -1)) /* not interned? */
-	{
-	    lua_pop(L, 1);
-	    b = luaV_newbuffer(L, buf);
-	}
-	else
-	    b = (luaV_Buffer *) lua_touserdata(L, -1);
-    }
-    return b;
+    else
+	luaV_pushtypval(L, &li->li_tv);
+    return 1;
+}
+
+static const luaL_Reg luaV_List_mt[] = {
+    {"__tostring", luaV_list_tostring},
+    {"__len", luaV_list_len},
+    {"__call", luaV_list_call},
+    {"__index", luaV_list_index},
+    {NULL, NULL}
+};
+
+
+/* =======   Dict type   ======= */
+
+    static int
+luaV_dict_len (lua_State *L)
+{
+    dict_T *d = (dict_T *) luaV_checkvalid(L, luaV_Dict, 1);
+    lua_pushinteger(L, (d == NULL) ? 0 : (int) d->dv_hashtab.ht_used);
+    return 1;
 }
 
-/* Buffer metamethods */
+    static int
+luaV_dict_iter (lua_State *L)
+{
+    hashitem_T *hi = (hashitem_T *) lua_touserdata(L, lua_upvalueindex(2));
+    int n = lua_tointeger(L, lua_upvalueindex(3));
+    dictitem_T *di;
+    if (n <= 0) return 0;
+    while (HASHITEM_EMPTY(hi)) hi++;
+    di = dict_lookup(hi);
+    lua_pushstring(L, (char *) hi->hi_key);
+    luaV_pushtypval(L, &di->di_tv);
+    lua_pushlightuserdata(L, (void *) (hi + 1));
+    lua_replace(L, lua_upvalueindex(2));
+    lua_pushinteger(L, n - 1);
+    lua_replace(L, lua_upvalueindex(3));
+    return 2;
+}
 
     static int
-luaV_buffer_tostring(lua_State *L)
+luaV_dict_call (lua_State *L)
+{
+    dict_T *d = (dict_T *) luaV_checkvalid(L, luaV_Dict, 1);
+    hashtab_T *ht = &d->dv_hashtab;
+    lua_pushvalue(L, lua_upvalueindex(1)); /* pass cache table along */
+    lua_pushlightuserdata(L, (void *) ht->ht_array);
+    lua_pushinteger(L, ht->ht_used); /* # remaining items */
+    lua_pushcclosure(L, luaV_dict_iter, 3);
+    return 1;
+}
+
+    static int
+luaV_dict_index (lua_State *L)
 {
-    lua_pushfstring(L, "%s: %p", LUAVIM_BUFFER, lua_touserdata(L, 1));
+    dict_T *d = (dict_T *) luaV_checkvalid(L, luaV_Dict, 1);
+    char_u *key = (char_u *) luaL_checkstring(L, 2);
+    dictitem_T *di = dict_find(d, key, -1);
+    if (di == NULL)
+	lua_pushnil(L);
+    else
+	luaV_pushtypval(L, &di->di_tv);
     return 1;
 }
 
+static const luaL_Reg luaV_Dict_mt[] = {
+    {"__tostring", luaV_dict_tostring},
+    {"__len", luaV_dict_len},
+    {"__call", luaV_dict_call},
+    {"__index", luaV_dict_index},
+    {NULL, NULL}
+};
+
+
+/* =======   Buffer type   ======= */
+
     static int
 luaV_buffer_len(lua_State *L)
 {
-    luaV_Buffer *b = lua_touserdata(L, 1);
-    lua_pushinteger(L, (*b)->b_ml.ml_line_count);
+    buf_T *b = (buf_T *) luaV_checkvalid(L, luaV_Buffer, 1);
+    lua_pushinteger(L, b->b_ml.ml_line_count);
     return 1;
 }
 
     static int
 luaV_buffer_call(lua_State *L)
 {
-    luaV_Buffer *b = (luaV_Buffer *) lua_touserdata(L, 1);
+    buf_T *b = (buf_T *) luaV_checkvalid(L, luaV_Buffer, 1);
     lua_settop(L, 1);
-    set_curbuf(*b, DOBUF_SPLIT);
+    set_curbuf(b, DOBUF_SPLIT);
     return 1;
 }
 
     static int
 luaV_buffer_index(lua_State *L)
 {
-    luaV_Buffer *b = (luaV_Buffer *) lua_touserdata(L, 1);
+    buf_T *b = (buf_T *) luaV_checkvalid(L, luaV_Buffer, 1);
     linenr_T n = (linenr_T) lua_tointeger(L, 2);
-    if (n > 0 && n <= (*b)->b_ml.ml_line_count)
-	luaV_pushline(L, *b, n);
+    if (n > 0 && n <= b->b_ml.ml_line_count)
+	luaV_pushline(L, b, n);
     else if (lua_isstring(L, 2))
     {
 	const char *s = lua_tostring(L, 2);
 	if (strncmp(s, "name", 4) == 0)
-	    lua_pushstring(L, (char *) (*b)->b_sfname);
+	    lua_pushstring(L, (char *) b->b_sfname);
 	else if (strncmp(s, "fname", 5) == 0)
-	    lua_pushstring(L, (char *) (*b)->b_ffname);
+	    lua_pushstring(L, (char *) b->b_ffname);
 	else if (strncmp(s, "number", 6) == 0)
-	    lua_pushinteger(L, (*b)->b_fnum);
+	    lua_pushinteger(L, b->b_fnum);
 	/* methods */
 	else if (strncmp(s,   "insert", 6) == 0
 		|| strncmp(s, "next", 4) == 0
@@ -584,17 +762,17 @@
     static int
 luaV_buffer_newindex(lua_State *L)
 {
-    luaV_Buffer *b = (luaV_Buffer *) lua_touserdata(L, 1);
+    buf_T *b = (buf_T *) luaV_checkvalid(L, luaV_Buffer, 1);
     linenr_T n = (linenr_T) luaL_checkinteger(L, 2);
 #ifdef HAVE_SANDBOX
     luaV_checksandbox(L);
 #endif
-    if (n < 1 || n > (*b)->b_ml.ml_line_count)
+    if (n < 1 || n > b->b_ml.ml_line_count)
 	luaL_error(L, "invalid line number");
     if (lua_isnil(L, 3)) /* delete line */
     {
 	buf_T *buf = curbuf;
-	curbuf = *b;
+	curbuf = b;
 	if (u_savedel(n, 1L) == FAIL)
 	{
 	    curbuf = buf;
@@ -607,7 +785,7 @@
 	}
 	else {
 	    deleted_lines_mark(n, 1L);
-	    if (*b == curwin->w_buffer) /* fix cursor in current window? */
+	    if (b == curwin->w_buffer) /* fix cursor in current window? */
 	    {
 		if (curwin->w_cursor.lnum >= n)
 		{
@@ -627,7 +805,7 @@
     else if (lua_isstring(L, 3)) /* update line */
     {
 	buf_T *buf = curbuf;
-	curbuf = *b;
+	curbuf = b;
 	if (u_savesub(n) == FAIL)
 	{
 	    curbuf = buf;
@@ -640,7 +818,7 @@
 	}
 	else changed_bytes(n, 0);
 	curbuf = buf;
-	if (*b == curwin->w_buffer)
+	if (b == curwin->w_buffer)
 	    check_cursor_col();
     }
     else
@@ -651,8 +829,9 @@
     static int
 luaV_buffer_insert(lua_State *L)
 {
-    luaV_Buffer *b = luaV_checkudata(L, 1, LUAVIM_BUFFER);
-    linenr_T last = (*b)->b_ml.ml_line_count;
+    luaV_Buffer *lb = luaV_checkudata(L, 1, LUAVIM_BUFFER);
+    buf_T *b = (buf_T *) luaV_checkcache(L, (void *) *lb);
+    linenr_T last = b->b_ml.ml_line_count;
     linenr_T n = (linenr_T) luaL_optinteger(L, 3, last);
     buf_T *buf;
     luaL_checktype(L, 2, LUA_TSTRING);
@@ -664,7 +843,7 @@
     if (n > last) n = last;
     /* insert */
     buf = curbuf;
-    curbuf = *b;
+    curbuf = b;
     if (u_save(n, n + 1) == FAIL)
     {
 	curbuf = buf;
@@ -686,7 +865,8 @@
 luaV_buffer_next(lua_State *L)
 {
     luaV_Buffer *b = luaV_checkudata(L, 1, LUAVIM_BUFFER);
-    luaV_pushbuffer(L, (*b)->b_next);
+    buf_T *buf = (buf_T *) luaV_checkcache(L, (void *) *b);
+    luaV_pushbuffer(L, buf->b_next);
     return 1;
 }
 
@@ -694,7 +874,8 @@
 luaV_buffer_previous(lua_State *L)
 {
     luaV_Buffer *b = luaV_checkudata(L, 1, LUAVIM_BUFFER);
-    luaV_pushbuffer(L, (*b)->b_prev);
+    buf_T *buf = (buf_T *) luaV_checkcache(L, (void *) *b);
+    luaV_pushbuffer(L, buf->b_prev);
     return 1;
 }
 
@@ -702,8 +883,7 @@
 luaV_buffer_isvalid(lua_State *L)
 {
     luaV_Buffer *b = luaV_checkudata(L, 1, LUAVIM_BUFFER);
-    lua_pushlightuserdata(L, (void *) (*b));
-    lua_rawget(L, LUA_ENVIRONINDEX);
+    luaV_getudata(L, *b);
     lua_pushboolean(L, !lua_isnil(L, -1));
     return 1;
 }
@@ -724,78 +904,32 @@
 
 /* =======   Window type   ======= */
 
-    static luaV_Window *
-luaV_newwindow(lua_State *L, win_T *win)
-{
-    luaV_Window *w = (luaV_Window *) lua_newuserdata(L, sizeof(luaV_Window));
-    *w = win;
-    lua_pushlightuserdata(L, (void *) win);
-    lua_pushvalue(L, -2);
-    lua_rawset(L, LUA_ENVIRONINDEX); /* env[win] = udata */
-    /* to avoid GC, store as key in env */
-    lua_pushvalue(L, -1);
-    lua_pushboolean(L, 1);
-    lua_rawset(L, LUA_ENVIRONINDEX); /* env[udata] = true */
-    /* set metatable */
-    luaV_getfield(L, LUAVIM_WINDOW);
-    lua_setmetatable(L, -2);
-    return w;
-}
-
-    static luaV_Window *
-luaV_pushwindow(lua_State *L, win_T *win)
-{
-    luaV_Window *w = NULL;
-    if (win == NULL)
-	lua_pushnil(L);
-    else {
-	lua_pushlightuserdata(L, (void *) win);
-	lua_rawget(L, LUA_ENVIRONINDEX);
-	if (lua_isnil(L, -1)) /* not interned? */
-	{
-	    lua_pop(L, 1);
-	    w = luaV_newwindow(L, win);
-	}
-	else w = (luaV_Window *) lua_touserdata(L, -1);
-    }
-    return w;
-}
-
-/* Window metamethods */
-
-    static int
-luaV_window_tostring(lua_State *L)
-{
-    lua_pushfstring(L, "%s: %p", LUAVIM_WINDOW, lua_touserdata(L, 1));
-    return 1;
-}
-
     static int
 luaV_window_call(lua_State *L)
 {
-    luaV_Window *w = (luaV_Window *) lua_touserdata(L, 1);
+    win_T *w = (win_T *) luaV_checkvalid(L, luaV_Window, 1);
     lua_settop(L, 1);
-    win_goto(*w);
+    win_goto(w);
     return 1;
 }
 
     static int
 luaV_window_index(lua_State *L)
 {
-    luaV_Window *w = (luaV_Window *) lua_touserdata(L, 1);
+    win_T *w = (win_T *) luaV_checkvalid(L, luaV_Window, 1);
     const char *s = luaL_checkstring(L, 2);
     if (strncmp(s, "buffer", 6) == 0)
-	luaV_pushbuffer(L, (*w)->w_buffer);
+	luaV_pushbuffer(L, w->w_buffer);
     else if (strncmp(s, "line", 4) == 0)
-	lua_pushinteger(L, (*w)->w_cursor.lnum);
+	lua_pushinteger(L, w->w_cursor.lnum);
     else if (strncmp(s, "col", 3) == 0)
-	lua_pushinteger(L, (*w)->w_cursor.col + 1);
+	lua_pushinteger(L, w->w_cursor.col + 1);
 #ifdef FEAT_VERTSPLIT
     else if (strncmp(s, "width", 5) == 0)
-	lua_pushinteger(L, W_WIDTH((*w)));
+	lua_pushinteger(L, W_WIDTH(w));
 #endif
     else if (strncmp(s, "height", 6) == 0)
-	lua_pushinteger(L, (*w)->w_height);
+	lua_pushinteger(L, w->w_height);
     /* methods */
     else if (strncmp(s,   "next", 4) == 0
 	    || strncmp(s, "previous", 8) == 0
@@ -812,7 +946,7 @@
     static int
 luaV_window_newindex (lua_State *L)
 {
-    luaV_Window *w = (luaV_Window *) lua_touserdata(L, 1);
+    win_T *w = (win_T *) luaV_checkvalid(L, luaV_Window, 1);
     const char *s = luaL_checkstring(L, 2);
     int v = luaL_checkinteger(L, 3);
     if (strncmp(s, "line", 4) == 0)
@@ -820,9 +954,9 @@
 #ifdef HAVE_SANDBOX
 	luaV_checksandbox(L);
 #endif
-	if (v < 1 || v > (*w)->w_buffer->b_ml.ml_line_count)
+	if (v < 1 || v > w->w_buffer->b_ml.ml_line_count)
 	    luaL_error(L, "line out of range");
-	(*w)->w_cursor.lnum = v;
+	w->w_cursor.lnum = v;
 	update_screen(VALID);
     }
     else if (strncmp(s, "col", 3) == 0)
@@ -830,7 +964,7 @@
 #ifdef HAVE_SANDBOX
 	luaV_checksandbox(L);
 #endif
-	(*w)->w_cursor.col = v - 1;
+	w->w_cursor.col = v - 1;
 	update_screen(VALID);
     }
 #ifdef FEAT_VERTSPLIT
@@ -840,7 +974,7 @@
 #ifdef FEAT_GUI
 	need_mouse_correct = TRUE;
 #endif
-	curwin = *w;
+	curwin = w;
 	win_setwidth(v);
 	curwin = win;
     }
@@ -851,7 +985,7 @@
 #ifdef FEAT_GUI
 	need_mouse_correct = TRUE;
 #endif
-	curwin = *w;
+	curwin = w;
 	win_setheight(v);
 	curwin = win;
     }
@@ -864,7 +998,8 @@
 luaV_window_next(lua_State *L)
 {
     luaV_Window *w = luaV_checkudata(L, 1, LUAVIM_WINDOW);
-    luaV_pushwindow(L, (*w)->w_next);
+    win_T *win = (win_T *) luaV_checkcache(L, (void *) *w);
+    luaV_pushwindow(L, win->w_next);
     return 1;
 }
 
@@ -872,7 +1007,8 @@
 luaV_window_previous(lua_State *L)
 {
     luaV_Window *w = luaV_checkudata(L, 1, LUAVIM_WINDOW);
-    luaV_pushwindow(L, (*w)->w_prev);
+    win_T *win = (win_T *) luaV_checkcache(L, (void *) *w);
+    luaV_pushwindow(L, win->w_prev);
     return 1;
 }
 
@@ -880,8 +1016,7 @@
 luaV_window_isvalid(lua_State *L)
 {
     luaV_Window *w = luaV_checkudata(L, 1, LUAVIM_WINDOW);
-    lua_pushlightuserdata(L, (void *) (*w));
-    lua_rawget(L, LUA_ENVIRONINDEX);
+    luaV_getudata(L, *w);
     lua_pushboolean(L, !lua_isnil(L, -1));
     return 1;
 }
@@ -1008,15 +1143,10 @@
 		    break;
 	    }
 	}
-	if (buf == NULL) /* not found? */
-	    lua_pushnil(L);
-	else
-	    luaV_pushbuffer(L, buf);
     }
-    else {
+    else
 	buf = (lua_toboolean(L, 1)) ? firstbuf : curbuf; /* first buffer? */
-	luaV_pushbuffer(L, buf);
-    }
+    luaV_pushbuffer(L, buf);
     return 1;
 }
 
@@ -1029,15 +1159,10 @@
 	int n = lua_tointeger(L, 1);
 	for (win = firstwin; win != NULL; win = win->w_next, n--)
 	    if (n == 1) break;
-	if (win == NULL) /* not found? */
-	    lua_pushnil(L);
-	else
-	    luaV_pushwindow(L, win);
     }
-    else {
+    else
 	win = (lua_toboolean(L, 1)) ? firstwin : curwin; /* first window? */
-	luaV_pushwindow(L, win);
-    }
+    luaV_pushwindow(L, win);
     return 1;
 }
 
@@ -1067,19 +1192,12 @@
     return 1;
 }
 
-/* for freeing buffer and window objects; lightuserdata as arg */
+/* for freeing list, dict, buffer and window objects; lightuserdata as arg */
     static int
 luaV_free(lua_State *L)
 {
-    lua_pushvalue(L, 1); /* lightudata */
-    lua_rawget(L, LUA_ENVIRONINDEX);
-    if (!lua_isnil(L, -1))
-    {
-	lua_pushnil(L);
-	lua_rawset(L, LUA_ENVIRONINDEX); /* env[udata] = nil */
-	lua_pushnil(L);
-	lua_rawset(L, LUA_ENVIRONINDEX); /* env[lightudata] = nil */
-    }
+    lua_pushnil(L);
+    luaV_setudata(L, lua_touserdata(L, 1));
     return 0;
 }
 
@@ -1099,13 +1217,8 @@
     static int
 luaopen_vim(lua_State *L)
 {
-    /* set environment */
+    /* set cache table */
     lua_newtable(L);
-    lua_newtable(L);
-    lua_pushliteral(L, "v");
-    lua_setfield(L, -2, "__mode");
-    lua_setmetatable(L, -2);
-    lua_replace(L, LUA_ENVIRONINDEX);
     /* print */
     lua_pushcfunction(L, luaV_print);
     lua_setglobal(L, "print");
@@ -1116,14 +1229,26 @@
     lua_pop(L, 1);
     /* free */
     lua_pushlightuserdata(L, (void *) LUAVIM_FREE);
-    lua_pushcfunction(L, luaV_free);
+    lua_pushvalue(L, 1); /* cache table */
+    lua_pushcclosure(L, luaV_free, 1);
     lua_rawset(L, LUA_REGISTRYINDEX);
     /* register */
+    luaV_newmetatable(L, LUAVIM_LIST);
+    lua_pushvalue(L, 1);
+    luaV_openlib(L, luaV_List_mt, 1);
+    luaV_newmetatable(L, LUAVIM_DICT);
+    lua_pushvalue(L, 1);
+    luaV_openlib(L, luaV_Dict_mt, 1);
     luaV_newmetatable(L, LUAVIM_BUFFER);
-    luaL_register(L, NULL, luaV_Buffer_mt);
+    lua_pushvalue(L, 1); /* cache table */
+    luaV_openlib(L, luaV_Buffer_mt, 1);
     luaV_newmetatable(L, LUAVIM_WINDOW);
-    luaL_register(L, NULL, luaV_Window_mt);
-    luaL_register(L, LUAVIM_NAME, luaV_module);
+    lua_pushvalue(L, 1); /* cache table */
+    luaV_openlib(L, luaV_Window_mt, 1);
+    lua_newtable(L); /* vim table */
+    lua_pushvalue(L, 1); /* cache table */
+    luaV_openlib(L, luaV_module, 1);
+    lua_setglobal(L, LUAVIM_NAME);
     return 0;
 }
 
@@ -1154,7 +1279,7 @@
 static lua_State *L = NULL;
 
     static int
-lua_is_open(void)
+lua_isopen(void)
 {
     return L != NULL;
 }
@@ -1162,7 +1287,7 @@
     static int
 lua_init(void)
 {
-    if (L == NULL)
+    if (!lua_isopen())
     {
 #ifdef DYNAMIC_LUA
 	if (!lua_enabled(TRUE))
@@ -1179,7 +1304,7 @@
     void
 lua_end(void)
 {
-    if (L != NULL)
+    if (lua_isopen())
     {
 	lua_close(L);
 	L = NULL;
@@ -1273,24 +1398,19 @@
     }
 }
 
-/* buffer */
-    void
-lua_buffer_free(buf_T *buf)
-{
-    if (!lua_is_open()) return;
-    luaV_getfield(L, LUAVIM_FREE);
-    lua_pushlightuserdata(L, (void *) buf);
-    lua_call(L, 1, 0);
-}
+#define luaV_freetype(typ,tname) \
+	void \
+    lua_##tname##_free(typ *o) \
+    { \
+	if (!lua_isopen()) return; \
+	luaV_getfield(L, LUAVIM_FREE); \
+	lua_pushlightuserdata(L, (void *) o); \
+	lua_call(L, 1, 0); \
+    }
 
-/* window */
-    void
-lua_window_free(win_T *win)
-{
-    if (!lua_is_open()) return;
-    luaV_getfield(L, LUAVIM_FREE);
-    lua_pushlightuserdata(L, (void *) win);
-    lua_call(L, 1, 0);
-}
+luaV_freetype(list_T, list)
+luaV_freetype(dict_T, dict)
+luaV_freetype(buf_T, buffer)
+luaV_freetype(win_T, window)
 
 #endif
diff -Naur src.orig/proto/if_lua.pro src/proto/if_lua.pro
--- src.orig/proto/if_lua.pro	2012-01-12 12:14:40.871873457 -0500
+++ src/proto/if_lua.pro	2012-01-12 10:58:52.531949069 -0500
@@ -4,6 +4,8 @@
 void ex_lua __ARGS((exarg_T *eap));
 void ex_luado __ARGS((exarg_T *eap));
 void ex_luafile __ARGS((exarg_T *eap));
+void lua_list_free __ARGS((list_T *lis));
+void lua_dict_free __ARGS((dict_T *dic));
 void lua_buffer_free __ARGS((buf_T *buf));
 void lua_window_free __ARGS((win_T *win));
 /* vim: set ft=c : */

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