From 8980c630bf40e05dad71ded377e3d0f0a17b076c Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Mon, 20 Dec 2010 15:25:36 -0200
Subject: error when indexing strings with invalid keys
---
lstrlib.c | 26 +++++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)
(limited to 'lstrlib.c')
diff --git a/lstrlib.c b/lstrlib.c
index 3acaf875..379fd20f 100644
--- a/lstrlib.c
+++ b/lstrlib.c
@@ -1,5 +1,5 @@
/*
-** $Id: lstrlib.c,v 1.159 2010/11/19 16:25:51 roberto Exp roberto $
+** $Id: lstrlib.c,v 1.160 2010/12/10 19:03:46 roberto Exp roberto $
** Standard library for string operations and pattern-matching
** See Copyright Notice in lua.h
*/
@@ -903,6 +903,15 @@ static int str_format (lua_State *L) {
/* }====================================================== */
+static int noindex (lua_State *L) {
+ const char *f = lua_tostring(L, 2);
+ if (f)
+ return luaL_error(L, "no field '%s' in strings", f);
+ else
+ return luaL_error(L, "no such field in strings");
+}
+
+
static const luaL_Reg strlib[] = {
{"byte", str_byte},
{"char", str_char},
@@ -918,19 +927,22 @@ static const luaL_Reg strlib[] = {
{"reverse", str_reverse},
{"sub", str_sub},
{"upper", str_upper},
+ {"__index", noindex},
{NULL, NULL}
};
static void createmetatable (lua_State *L) {
- lua_createtable(L, 0, 1); /* create metatable for strings */
+ /* setmetatable("", {__index = string}) */
lua_pushliteral(L, ""); /* dummy string */
- lua_pushvalue(L, -2);
- lua_setmetatable(L, -2); /* set string metatable */
+ lua_createtable(L, 0, 1); /* create metatable for strings */
+ lua_pushvalue(L, -3); /* set the string library... */
+ lua_setfield(L, -2, "__index"); /* ...as the __index metamethod */
+ lua_setmetatable(L, -2); /* set metatable for strings */
lua_pop(L, 1); /* pop dummy string */
- lua_pushvalue(L, -2); /* string library... */
- lua_setfield(L, -2, "__index"); /* ...is the __index metamethod */
- lua_pop(L, 1); /* pop metatable */
+ /* setmetatable(string, string) */
+ lua_pushvalue(L, -1); /* push string library */
+ lua_setmetatable(L, -2); /* set it as its own metatable */
}
--
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