Add in_lua flag

In preparation of making config errors available to lua scripts,
instead outputting them via pline.

include/extern.h

@@ -1646,6 +1646,7 @@ extern int l_obj_register(lua_State *);
 
 #if !defined(CROSSCOMPILE) || defined(CROSSCOMPILE_TARGET)
 extern lua_State * nhl_init(void);
+extern void nhl_done(lua_State *);
 extern boolean nhl_loadlua(lua_State *, const char *);
 extern boolean load_lua(const char *);
 extern void nhl_error(lua_State *, const char *) NORETURN;

include/flag.h

@@ -174,6 +174,7 @@ struct instance_flags {
      * a structure of their own elsewhere some day.
      */
     boolean debug_fuzzer;  /* fuzz testing */
+    boolean in_lua;        /* executing a lua script */
     boolean defer_plname;  /* X11 hack: askname() might not set g.plname */
     boolean herecmd_menu;  /* use menu when mouseclick on yourself */
     boolean invis_goldsym; /* gold symbol is ' '? */

src/dungeon.c

@@ -1175,7 +1175,7 @@ init_dungeons(void)
            so that it's hidden from '#wizwhere' feedback. */
     }
 
-    lua_close(L);
+    nhl_done(L);
 
     for (i = 0; i < pd.n_brs; i++) {
         free((genericptr_t) pd.tmpbranch[i].name);

src/mklev.c

@@ -259,7 +259,7 @@ free_luathemes(boolean keependgame) /* False: exiting, True: discarding main dun
         if (keependgame && i == astral_level.dnum)
             continue;
         if (g.luathemes[i]) {
-            lua_close((lua_State *) g.luathemes[i]);
+            nhl_done((lua_State *) g.luathemes[i]);
             g.luathemes[i] = (lua_State *) 0;
         }
     }
@@ -277,7 +277,7 @@ makerooms(void)
         if ((themes = nhl_init()) != 0) {
             if (!nhl_loadlua(themes, fname)) {
                 /* loading lua failed, don't use themed rooms */
-                lua_close(themes);
+                nhl_done(themes);
                 themes = (lua_State *) 0;
             } else {
                 /* success; save state for this dungeon branch */

src/nhlua.c

@@ -1110,6 +1110,7 @@ nhl_init(void)
 {
     lua_State *L = luaL_newstate();
 
+    iflags.in_lua = TRUE;
     luaL_openlibs(L);
     nhl_set_package_path(L, "./?.lua");
 
@@ -1130,13 +1131,20 @@ nhl_init(void)
     l_obj_register(L);
 
     if (!nhl_loadlua(L, "nhlib.lua")) {
-        lua_close(L);
+        nhl_done(L);
         return (lua_State *) 0;
     }
 
     return L;
 }
 
+void
+nhl_done(lua_State *L)
+{
+    lua_close(L);
+    iflags.in_lua = FALSE;
+}
+
 boolean
 load_lua(const char *name)
 {
@@ -1154,7 +1162,7 @@ load_lua(const char *name)
     }
 
  give_up:
-    lua_close(L);
+    nhl_done(L);
 
     return ret;
 }

src/questpgr.c

@@ -542,7 +542,7 @@ com_pager_core(const char *section, const char *msgid, boolean showerror)
         free((genericptr_t) synopsis);
     if (fallback_msgid)
         free((genericptr_t) fallback_msgid);
-    lua_close(L);
+    nhl_done(L);
     return res;
 }