first step towards _ENV: all chunks have an puvalues _ENV with the

global table

lapi.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lapi.c,v 2.112 2010/01/21 16:49:21 roberto Exp roberto $
+** $Id: lapi.c,v 2.113 2010/02/09 11:55:37 roberto Exp roberto $
 ** Lua API
 ** See Copyright Notice in lua.h
 */
@@ -882,6 +882,12 @@ LUA_API int lua_load (lua_State *L, lua_Reader reader, void *data,
   if (!chunkname) chunkname = "?";
   luaZ_init(L, &z, reader, data);
   status = luaD_protectedparser(L, &z, chunkname);
+  if (status == LUA_OK) {
+    Closure *f = clvalue(L->top - 1);
+    lua_assert(!f->c.isC);
+    if (f->l.nupvalues == 1)
+        sethvalue(L, f->l.upvals[0]->v, G(L)->l_gt);
+  }
   lua_unlock(L);
   return status;
 }

llex.h

@@ -1,5 +1,5 @@
 /*
-** $Id: llex.h,v 1.61 2007/10/25 16:45:47 roberto Exp roberto $
+** $Id: llex.h,v 1.62 2009/10/11 20:02:19 roberto Exp roberto $
 ** Lexical Analyzer
 ** See Copyright Notice in lua.h
 */
@@ -60,6 +60,7 @@ typedef struct LexState {
   Mbuffer *buff;  /* buffer for tokens */
   struct Varlist *varl;  /* list of all active local variables */
   TString *source;  /* current source name */
+  TString *envn;  /* name of environment variable */
   char decpoint;  /* locale decimal point */
 } LexState;
 

lparser.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lparser.c,v 2.76 2010/02/26 20:40:29 roberto Exp roberto $
+** $Id: lparser.c,v 2.77 2010/03/04 18:12:57 roberto Exp roberto $
 ** Lua Parser
 ** See Copyright Notice in lua.h
 */
@@ -224,10 +224,10 @@ static int newupvalue (FuncState *fs, TString *name, expdesc *v) {
   luaM_growvector(fs->L, f->upvalues, fs->nups, f->sizeupvalues,
                   Upvaldesc, UCHAR_MAX, "upvalues");
   while (oldsize < f->sizeupvalues) f->upvalues[oldsize++].name = NULL;
-  f->upvalues[fs->nups].name = name;
-  luaC_objbarrier(fs->L, f, name);
   f->upvalues[fs->nups].instack = (v->k == VLOCAL);
   f->upvalues[fs->nups].idx = cast_byte(v->u.s.info);
+  f->upvalues[fs->nups].name = name;
+  luaC_objbarrier(fs->L, f, name);
   return fs->nups++;
 }
 
@@ -430,26 +430,39 @@ static void close_func (LexState *ls) {
 }
 
 
+/*
+** opens the main function, which is a regular vararg function with an
+** upvalue named '_ENV'
+*/
+static void open_mainfunc (lua_State *L, LexState *ls, FuncState *fs) {
+  expdesc v;
+  open_func(ls, fs);
+  fs->f->is_vararg = 1;  /* main function is always vararg */
+  ls->envn = luaS_new(L, "_ENV");  /* create '_ENV' string */
+  setsvalue2s(L, L->top++, ls->envn);  /* anchor it */
+  init_exp(&v, VLOCAL, 0);
+  newupvalue(fs, ls->envn, &v);  /* create '_ENV' upvalue */
+  L->top--;  /* now string is anchored as an upvalue name */
+}
+
+
 Proto *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, Varlist *varl,
                     const char *name) {
-  struct LexState lexstate;
-  struct FuncState funcstate;
+  LexState lexstate;
+  FuncState funcstate;
   TString *tname = luaS_new(L, name);
   setsvalue2s(L, L->top, tname);  /* push name to protect it */
   incr_top(L);
   lexstate.buff = buff;
   lexstate.varl = varl;
   luaX_setinput(L, &lexstate, z, tname);
-  open_func(&lexstate, &funcstate);
-  funcstate.f->is_vararg = 1;  /* main function is always vararg */
+  open_mainfunc(L, &lexstate, &funcstate);
   luaX_next(&lexstate);  /* read first token */
-  chunk(&lexstate);
+  chunk(&lexstate);  /* read main chunk */
   check(&lexstate, TK_EOS);
   close_func(&lexstate);
   L->top--;  /* pop name */
-  lua_assert(funcstate.prev == NULL);
-  lua_assert(funcstate.nups == 0);
-  lua_assert(lexstate.fs == NULL);
+  lua_assert(!funcstate.prev && funcstate.nups == 1 && !lexstate.fs);
   return funcstate.f;
 }