From 924bed7297d5ea16a78ec07e7acc64afad951aa8 Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Mon, 1 Jul 2019 12:25:00 -0300
Subject: Methods separated from metamethods in 'io'
In the 'io' library, changed the use of the metatable also as its
own "method table", so that metamethods cannot be accessed as if they
were methods. (For instance, 'io.stdin.__gc' does not result in
the finalizer metamethod anymore.)
---
liolib.c | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)
diff --git a/liolib.c b/liolib.c
index 1484676d..2c0c6a3b 100644
--- a/liolib.c
+++ b/liolib.c
@@ -742,14 +742,23 @@ static const luaL_Reg iolib[] = {
/*
** methods for file handles
*/
-static const luaL_Reg flib[] = {
- {"close", f_close},
- {"flush", f_flush},
- {"lines", f_lines},
+static const luaL_Reg meth[] = {
{"read", f_read},
+ {"write", f_write},
+ {"lines", f_lines},
+ {"flush", f_flush},
{"seek", f_seek},
+ {"close", f_close},
{"setvbuf", f_setvbuf},
- {"write", f_write},
+ {NULL, NULL}
+};
+
+
+/*
+** metamethods for file handles
+*/
+static const luaL_Reg metameth[] = {
+ {"__index", NULL}, /* place holder */
{"__gc", f_gc},
{"__close", f_gc},
{"__tostring", f_tostring},
@@ -758,11 +767,12 @@ static const luaL_Reg flib[] = {
static void createmeta (lua_State *L) {
- luaL_newmetatable(L, LUA_FILEHANDLE); /* create metatable for file handles */
- lua_pushvalue(L, -1); /* push metatable */
- lua_setfield(L, -2, "__index"); /* metatable.__index = metatable */
- luaL_setfuncs(L, flib, 0); /* add file methods to new metatable */
- lua_pop(L, 1); /* pop new metatable */
+ luaL_newmetatable(L, LUA_FILEHANDLE); /* metatable for file handles */
+ luaL_setfuncs(L, metameth, 0); /* add metamethods to new metatable */
+ luaL_newlibtable(L, meth); /* create method table */
+ luaL_setfuncs(L, meth, 0); /* add file methods to method table */
+ lua_setfield(L, -2, "__index"); /* metatable.__index = method table */
+ lua_pop(L, 1); /* pop metatable */
}
--
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