lua

commit 924bed7297d5ea16a78ec07e7acc64afad951aa8
parent 8b7cfee26b71e66de2cef9f8db9d9e18f5439afd
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date:   Mon,  1 Jul 2019 12:24:33 -0300

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.)

Diffstat:
M
liolib.c
 | 
30
++++++++++++++++++++----------

1 file changed, 20 insertions(+), 10 deletions(-)
diff --git 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 */
 }