diff --git a/scripts/eressea/tunnels.lua b/scripts/eressea/tunnels.lua
index b0b3fe2a3..4a787a373 100644
--- a/scripts/eressea/tunnels.lua
+++ b/scripts/eressea/tunnels.lua
@@ -27,7 +27,6 @@ end
 local function tunnel_action(b, param)
   local units = tunnel_travelers(b)
   local rto = get_target(param)
-  print("tunnel from " .. tostring(b.region) .. " to " .. tostring(rto))
   if rto and units then
     eressea.log.debug("Tunnel from " .. tostring(b) .. " [" .. param .. "]")
     for key, u in pairs(units) do
diff --git a/scripts/eressea/xmasitems.lua b/scripts/eressea/xmasitems.lua
index a0f2e48f8..3771553b5 100644
--- a/scripts/eressea/xmasitems.lua
+++ b/scripts/eressea/xmasitems.lua
@@ -74,7 +74,7 @@ function use_xmastree(u, amount)
     if u.region.herb~=nil then
         -- TODO: else?
         local trees = u.region:get_resource("tree")
-        u.region:set_key("xm06", true)
+        u.region:set_key("xm06", get_turn())
         u.region:set_resource("tree", 10+trees)
         local msg = usepotion_message(u, "xmastree")
         msg:send_region(u.region)
@@ -107,7 +107,7 @@ function self.update()
             -- we celebrate knut and kick out the trees.
             for r in regions() do
                 if r:get_key("xm06") then
-                    r:set_key("xm06", false)
+                    r:set_key("xm06", 0)
                 end
             end
         end
diff --git a/scripts/tests/common.lua b/scripts/tests/common.lua
index 403db0a46..944b0bdfe 100644
--- a/scripts/tests/common.lua
+++ b/scripts/tests/common.lua
@@ -1135,3 +1135,24 @@ function test_immunity_stops_guard()
     assert_equal(f.age, 2)
     assert_true(u.guard)
 end
+
+function test_region_keys()
+    local r = region.create(0, 0, 'plain')
+    assert_nil(r:get_key('test'))
+    assert_nil(r:get_key('more'))
+    r:set_key('test', 42)
+    r:set_key('more') -- default is 1
+    assert_equal(42, r:get_key('test'))
+    assert_equal(1, r:get_key('more'))
+end
+
+function test_faction_keys()
+    local f = faction.create('human')
+    assert_nil(f:get_key('test'))
+    assert_nil(f:get_key('more'))
+    f:set_key('test', 42)
+    f:set_key('more') -- default is 1
+    assert_equal(42, f:get_key('test'))
+    assert_equal(1, f:get_key('more'))
+end
+
diff --git a/scripts/tests/xmas.lua b/scripts/tests/xmas.lua
index 304cc333a..8ae85fc76 100644
--- a/scripts/tests/xmas.lua
+++ b/scripts/tests/xmas.lua
@@ -75,9 +75,11 @@ end
 function test_xmastree()
     local r
     r = use_tree("ocean")
+    assert_nil(r:get_key("xm06")) 
     assert_equal(0, r:get_resource("tree"))
     eressea.free_game()
     r = use_tree("plain")
+    assert_equal(get_turn(), r:get_key("xm06")) 
     assert_equal(10, r:get_resource("tree"))
 end
 
diff --git a/src/battle.c b/src/battle.c
index 3a1628dfe..326e05e20 100644
--- a/src/battle.c
+++ b/src/battle.c
@@ -340,7 +340,7 @@ bool helping(const side * as, const side * ds)
 {
     if (as->faction == ds->faction)
         return true;
-    return (bool)(!enemy(as, ds) && alliedside(as, ds->faction, HELP_FIGHT));
+    return (!enemy(as, ds) && alliedside(as, ds->faction, HELP_FIGHT));
 }
 
 int statusrow(int status)
@@ -2640,7 +2640,7 @@ static void aftermath(battle * b)
     side *s;
     int dead_players = 0;
     bfaction *bf;
-    bool ships_damaged = (bool)(b->turn + (b->has_tactics_turn ? 1 : 0) > 2);      /* only used for ship damage! */
+    bool ships_damaged = (b->turn + (b->has_tactics_turn ? 1 : 0) > 2);      /* only used for ship damage! */
 
     for (s = b->sides; s != b->sides + b->nsides; ++s) {
         fighter *df;
diff --git a/src/bind_faction.c b/src/bind_faction.c
index 581b1b0bf..9cc6bdd97 100644
--- a/src/bind_faction.c
+++ b/src/bind_faction.c
@@ -59,7 +59,7 @@ int tolua_factionlist_next(lua_State * L)
 
 static int tolua_faction_get_units(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     unit **unit_ptr = (unit **)lua_newuserdata(L, sizeof(unit *));
 
     luaL_getmetatable(L, TOLUA_CAST "unit");
@@ -73,8 +73,8 @@ static int tolua_faction_get_units(lua_State * L)
 
 int tolua_faction_add_item(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
-    const char *iname = tolua_tostring(L, 2, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
+    const char *iname = tolua_tostring(L, 2, NULL);
     int number = (int)tolua_tonumber(L, 3, 0);
     int result = -1;
 
@@ -91,35 +91,35 @@ int tolua_faction_add_item(lua_State * L)
 
 static int tolua_faction_get_maxheroes(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, maxheroes(self));
     return 1;
 }
 
 static int tolua_faction_get_heroes(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, countheroes(self));
     return 1;
 }
 
 static int tolua_faction_get_score(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     lua_pushnumber(L, (lua_Number)self->score);
     return 1;
 }
 
 static int tolua_faction_get_id(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, self->no);
     return 1;
 }
 
 static int tolua_faction_set_id(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     int id = (int)tolua_tonumber(L, 2, 0);
     if (findfaction(id) == NULL) {
         renumber_faction(self, id);
@@ -133,15 +133,15 @@ static int tolua_faction_set_id(lua_State * L)
 
 static int tolua_faction_get_magic(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     lua_pushstring(L, magic_school[self->magiegebiet]);
     return 1;
 }
 
 static int tolua_faction_set_magic(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
-    const char *type = tolua_tostring(L, 2, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
+    const char *type = tolua_tostring(L, 2, NULL);
     int mtype;
 
     for (mtype = 0; mtype != MAXMAGIETYP; ++mtype) {
@@ -155,14 +155,14 @@ static int tolua_faction_set_magic(lua_State * L)
 
 static int tolua_faction_get_age(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, self->age);
     return 1;
 }
 
 static int tolua_faction_set_age(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     int age = (int)tolua_tonumber(L, 2, 0);
     self->age = age;
     return 0;
@@ -170,14 +170,14 @@ static int tolua_faction_set_age(lua_State * L)
 
 static int tolua_faction_get_flags(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, self->flags);
     return 1;
 }
 
 static int tolua_faction_set_flags(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     int flags = (int)tolua_tonumber(L, 2, self->flags);
     self->flags = flags;
     return 1;
@@ -185,14 +185,14 @@ static int tolua_faction_set_flags(lua_State * L)
 
 static int tolua_faction_get_options(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, self->options);
     return 1;
 }
 
 static int tolua_faction_set_options(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     int options = (int)tolua_tonumber(L, 2, self->options);
     self->options = options;
     return 1;
@@ -200,14 +200,14 @@ static int tolua_faction_set_options(lua_State * L)
 
 static int tolua_faction_get_lastturn(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, self->lastorders);
     return 1;
 }
 
 static int tolua_faction_set_lastturn(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     if (self) {
         self->lastorders = (int)tolua_tonumber(L, 2, self->lastorders);
     }
@@ -216,7 +216,7 @@ static int tolua_faction_set_lastturn(lua_State * L)
 
 static int tolua_faction_renumber(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     int no = (int)tolua_tonumber(L, 2, 0);
 
     renumber_faction(self, no);
@@ -225,8 +225,8 @@ static int tolua_faction_renumber(lua_State * L)
 
 static int tolua_faction_addnotice(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
-    const char *str = tolua_tostring(L, 2, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
+    const char *str = tolua_tostring(L, 2, NULL);
 
     addmessage(NULL, self, str, MSG_MESSAGE, ML_IMPORTANT);
     return 0;
@@ -234,19 +234,22 @@ static int tolua_faction_addnotice(lua_State * L)
 
 static int tolua_faction_getkey(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
-    const char *name = tolua_tostring(L, 2, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
+    const char *name = tolua_tostring(L, 2, NULL);
     int flag = atoi36(name);
-
-    lua_pushinteger(L, key_get(self->attribs, flag));
-    return 1;
+    int value = key_get(self->attribs, flag);
+    if (value != 0) {
+        lua_pushinteger(L, value);
+        return 1;
+    }
+    return 0;
 }
 
 static int tolua_faction_setkey(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
-    const char *name = tolua_tostring(L, 2, 0);
-    int value = (int)tolua_tonumber(L, 3, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
+    const char *name = tolua_tostring(L, 2, NULL);
+    int value = (int)tolua_tonumber(L, 3, 1);
     int flag = atoi36(name);
 
     if (value) {
@@ -260,7 +263,7 @@ static int tolua_faction_setkey(lua_State * L)
 
 static int tolua_faction_get_messages(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     int i = 1;
     mlist *ml;
     if (!self->msgs) {
@@ -276,8 +279,8 @@ static int tolua_faction_get_messages(lua_State * L)
 }
 
 static int tolua_faction_count_msg_type(lua_State *L) {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
-    const char *str = tolua_tostring(L, 2, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
+    const char *str = tolua_tostring(L, 2, NULL);
     int n = 0;
     if (self->msgs) {
         mlist * ml = self->msgs->begin;
@@ -294,8 +297,8 @@ static int tolua_faction_count_msg_type(lua_State *L) {
 
 static int tolua_faction_normalize(lua_State * L)
 {
-    faction *f = (faction *)tolua_tousertype(L, 1, 0);
-    region *r = (region *)tolua_tousertype(L, 2, 0);
+    faction *f = (faction *)tolua_tousertype(L, 1, NULL);
+    region *r = (region *)tolua_tousertype(L, 2, NULL);
     if (r) {
         plane *pl = rplane(r);
         int nx = r->x, ny = r->y;
@@ -310,8 +313,8 @@ static int tolua_faction_normalize(lua_State * L)
 
 static int tolua_faction_set_origin(lua_State * L)
 {
-    faction *f = (faction *)tolua_tousertype(L, 1, 0);
-    region *r = (region *)tolua_tousertype(L, 2, 0);
+    faction *f = (faction *)tolua_tousertype(L, 1, NULL);
+    region *r = (region *)tolua_tousertype(L, 2, NULL);
     plane *pl = rplane(r);
     int id = pl ? pl->id : 0;
 
@@ -321,7 +324,7 @@ static int tolua_faction_set_origin(lua_State * L)
 
 static int tolua_faction_get_origin(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     int x = 0, y = 0;
     faction_getorigin(self, 0, &x, &y);
 
@@ -332,7 +335,7 @@ static int tolua_faction_get_origin(lua_State * L)
 
 static int tolua_faction_destroy(lua_State * L)
 {
-    faction **fp, *f = (faction *)tolua_tousertype(L, 1, 0);
+    faction **fp, *f = (faction *)tolua_tousertype(L, 1, NULL);
     /* TODO: this loop is slow af, but what can we do? */
     for (fp = &factions; *fp; fp = &(*fp)->next) {
         if (*fp == f) {
@@ -353,9 +356,9 @@ static int tolua_faction_get(lua_State * L)
 
 static int tolua_faction_create(lua_State * L)
 {
-    const char *racename = tolua_tostring(L, 1, 0);
-    const char *email = tolua_tostring(L, 2, 0);
-    const char *lang = tolua_tostring(L, 3, 0);
+    const char *racename = tolua_tostring(L, 1, NULL);
+    const char *email = tolua_tostring(L, 2, NULL);
+    const char *lang = tolua_tostring(L, 3, NULL);
     struct locale *loc = lang ? get_locale(lang) : default_locale;
     faction *f = NULL;
     const struct race *frace = rc_find(racename ? racename : "human");
@@ -371,44 +374,44 @@ static int tolua_faction_create(lua_State * L)
 
 static int tolua_faction_get_password(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     tolua_pushstring(L, faction_getpassword(self));
     return 1;
 }
 
 static int tolua_faction_set_password(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
-    const char * passw = tolua_tostring(L, 2, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
+    const char * passw = tolua_tostring(L, 2, NULL);
     faction_setpassword(self, password_hash(passw, PASSWORD_DEFAULT));
     return 0;
 }
 
 static int tolua_faction_get_email(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     tolua_pushstring(L, faction_getemail(self));
     return 1;
 }
 
 static int tolua_faction_set_email(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
-    faction_setemail(self, tolua_tostring(L, 2, 0));
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
+    faction_setemail(self, tolua_tostring(L, 2, NULL));
     return 0;
 }
 
 static int tolua_faction_get_locale(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     tolua_pushstring(L, locale_name(self->locale));
     return 1;
 }
 
 static int tolua_faction_set_locale(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
-    const char *name = tolua_tostring(L, 2, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
+    const char *name = tolua_tostring(L, 2, NULL);
     const struct locale *loc = get_locale(name);
     if (loc) {
         self->locale = loc;
@@ -422,15 +425,15 @@ static int tolua_faction_set_locale(lua_State * L)
 
 static int tolua_faction_get_race(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     tolua_pushstring(L, self->race->_name);
     return 1;
 }
 
 static int tolua_faction_set_race(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
-    const char *name = tolua_tostring(L, 2, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
+    const char *name = tolua_tostring(L, 2, NULL);
     const race *rc = rc_find(name);
     if (rc != NULL) {
         self->race = rc;
@@ -441,57 +444,57 @@ static int tolua_faction_set_race(lua_State * L)
 
 static int tolua_faction_get_name(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     tolua_pushstring(L, faction_getname(self));
     return 1;
 }
 
 static int tolua_faction_set_name(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
-    faction_setname(self, tolua_tostring(L, 2, 0));
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
+    faction_setname(self, tolua_tostring(L, 2, NULL));
     return 0;
 }
 
 static int tolua_faction_get_uid(lua_State * L)
 {
-    faction *f = (faction *)tolua_tousertype(L, 1, 0);
+    faction *f = (faction *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, f->uid);
     return 1;
 }
 
 static int tolua_faction_set_uid(lua_State * L)
 {
-    faction *f = (faction *)tolua_tousertype(L, 1, 0);
+    faction *f = (faction *)tolua_tousertype(L, 1, NULL);
     f->uid = (int)tolua_tonumber(L, 2, 0);
     return 0;
 }
 
 static int tolua_faction_get_info(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     tolua_pushstring(L, faction_getbanner(self));
     return 1;
 }
 
 static int tolua_faction_set_info(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
-    faction_setbanner(self, tolua_tostring(L, 2, 0));
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
+    faction_setbanner(self, tolua_tostring(L, 2, NULL));
     return 0;
 }
 
 static int tolua_faction_get_alliance(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     tolua_pushusertype(L, f_get_alliance(self), TOLUA_CAST "alliance");
     return 1;
 }
 
 static int tolua_faction_set_alliance(lua_State * L)
 {
-    struct faction *self = (struct faction *)tolua_tousertype(L, 1, 0);
-    struct alliance *alli = (struct alliance *) tolua_tousertype(L, 2, 0);
+    struct faction *self = (struct faction *)tolua_tousertype(L, 1, NULL);
+    struct alliance *alli = (struct alliance *) tolua_tousertype(L, 2, NULL);
 
     setalliance(self, alli);
 
@@ -500,7 +503,7 @@ static int tolua_faction_set_alliance(lua_State * L)
 
 static int tolua_faction_get_items(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     item **item_ptr = (item **)lua_newuserdata(L, sizeof(item *));
 
     luaL_getmetatable(L, TOLUA_CAST "item");
@@ -515,7 +518,7 @@ static int tolua_faction_get_items(lua_State * L)
 
 static int tolua_faction_tostring(lua_State * L)
 {
-    faction *self = (faction *)tolua_tousertype(L, 1, 0);
+    faction *self = (faction *)tolua_tousertype(L, 1, NULL);
     lua_pushstring(L, factionname(self));
     return 1;
 }
diff --git a/src/bind_region.c b/src/bind_region.c
index 86c072a84..fd76a80b9 100644
--- a/src/bind_region.c
+++ b/src/bind_region.c
@@ -42,8 +42,8 @@
 #include <stdlib.h>
 
 static int tolua_region_count_msg_type(lua_State *L) {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
-    const char *str = tolua_tostring(L, 2, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
+    const char *str = tolua_tostring(L, 2, NULL);
     int n = 0;
     if (self->msgs) {
         mlist * ml = self->msgs->begin;
@@ -73,21 +73,21 @@ int tolua_regionlist_next(lua_State * L)
 
 static int tolua_region_get_id(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, self->uid);
     return 1;
 }
 
 static int tolua_region_get_blocked(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     lua_pushboolean(L, (self->flags&RF_BLOCKED) != 0);
     return 1;
 }
 
 static int tolua_region_set_blocked(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     bool flag = !!tolua_toboolean(L, 2, 1);
     if (flag) self->flags |= RF_BLOCKED;
     else self->flags &= ~RF_BLOCKED;
@@ -96,36 +96,36 @@ static int tolua_region_set_blocked(lua_State * L)
 
 static int tolua_region_get_x(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, self->x);
     return 1;
 }
 
 static int tolua_region_get_y(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, self->y);
     return 1;
 }
 
 static int tolua_region_get_plane(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
     tolua_pushusertype(L, rplane(r), TOLUA_CAST "plane");
     return 1;
 }
 
 static int tolua_region_get_terrain(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     tolua_pushstring(L, self->terrain->_name);
     return 1;
 }
 
 static int tolua_region_set_terrain(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
-    const char *tname = tolua_tostring(L, 2, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
+    const char *tname = tolua_tostring(L, 2, NULL);
     if (tname) {
         const terrain_type *terrain = get_terrain(tname);
         if (terrain) {
@@ -137,7 +137,7 @@ static int tolua_region_set_terrain(lua_State * L)
 
 static int tolua_region_get_terrainname(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     attrib *a = a_find(self->attribs, &at_racename);
     if (a) {
         tolua_pushstring(L, get_racename(a));
@@ -148,8 +148,8 @@ static int tolua_region_get_terrainname(lua_State * L)
 
 static int tolua_region_set_owner(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
-    struct faction *f = (struct faction *)tolua_tousertype(L, 2, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
+    struct faction *f = (struct faction *)tolua_tousertype(L, 2, NULL);
     if (r) {
         region_set_owner(r, f, turn);
     }
@@ -158,7 +158,7 @@ static int tolua_region_set_owner(lua_State * L)
 
 static int tolua_region_get_owner(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
     if (r) {
         struct faction *f = region_get_owner(r);
         tolua_pushusertype(L, f, TOLUA_CAST "faction");
@@ -169,8 +169,8 @@ static int tolua_region_get_owner(lua_State * L)
 
 static int tolua_region_set_terrainname(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
-    const char *name = tolua_tostring(L, 2, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
+    const char *name = tolua_tostring(L, 2, NULL);
     if (name == NULL) {
         a_removeall(&self->attribs, &at_racename);
     }
@@ -182,42 +182,42 @@ static int tolua_region_set_terrainname(lua_State * L)
 
 static int tolua_region_get_info(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     tolua_pushstring(L, region_getinfo(self));
     return 1;
 }
 
 static int tolua_region_set_info(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
-    region_setinfo(self, tolua_tostring(L, 2, 0));
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
+    region_setinfo(self, tolua_tostring(L, 2, NULL));
     return 0;
 }
 
 static int tolua_region_get_name(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     tolua_pushstring(L, region_getname(self));
     return 1;
 }
 
 static int tolua_region_set_name(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
-    region_setname(self, tolua_tostring(L, 2, 0));
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
+    region_setname(self, tolua_tostring(L, 2, NULL));
     return 0;
 }
 
 static int tolua_region_get_morale(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, region_get_morale(r));
     return 1;
 }
 
 static int tolua_region_set_morale(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
     region_set_morale(r, (int)tolua_tonumber(L, 2, 0), turn);
     return 0;
 }
@@ -225,14 +225,14 @@ static int tolua_region_set_morale(lua_State * L)
 /* region mourning this turn */
 static int tolua_region_get_is_mourning(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
     lua_pushboolean(L, is_mourning(r, turn+1));
     return 1;
 }
 
 static int tolua_region_get_adj(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
     region *rn[MAXDIRECTIONS];
     int d, idx;
     get_neighbours(r, rn);
@@ -249,7 +249,7 @@ static int tolua_region_get_adj(lua_State * L)
 
 static int tolua_region_get_luxury(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
     if (r->land) {
         const item_type *lux = r_luxury(r);
         if (lux) {
@@ -263,8 +263,8 @@ static int tolua_region_get_luxury(lua_State * L)
 
 static int tolua_region_set_luxury(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
-    const char *name = tolua_tostring(L, 2, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
+    const char *name = tolua_tostring(L, 2, NULL);
     if (r->land && name) {
         const item_type *lux = r_luxury(r);
         const item_type *itype = it_find(name);
@@ -278,9 +278,9 @@ static int tolua_region_set_luxury(lua_State * L)
 
 static int tolua_region_set_herb(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
     if (r->land) {
-        const char *name = tolua_tostring(L, 2, 0);
+        const char *name = tolua_tostring(L, 2, NULL);
         const item_type *itype = it_find(name);
         if (itype && (itype->flags & ITF_HERB)) {
             r->land->herbtype = itype;
@@ -291,7 +291,7 @@ static int tolua_region_set_herb(lua_State * L)
 
 static int tolua_region_get_herb(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
     if (r->land && r->land->herbtype) {
         const char *name = r->land->herbtype->rtype->_name;
         tolua_pushstring(L, name);
@@ -302,7 +302,7 @@ static int tolua_region_get_herb(lua_State * L)
 
 static int tolua_region_get_next(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     direction_t dir = (direction_t)tolua_tonumber(L, 2, 0);
 
     if (dir >= 0 && dir < MAXDIRECTIONS) {
@@ -314,7 +314,7 @@ static int tolua_region_get_next(lua_State * L)
 
 static int tolua_region_get_flag(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     int bit = (int)tolua_tonumber(L, 2, 0);
 
     lua_pushboolean(L, (self->flags & (1 << bit)));
@@ -323,7 +323,7 @@ static int tolua_region_get_flag(lua_State * L)
 
 static int tolua_region_set_flag(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     int bit = (int)tolua_tonumber(L, 2, 0);
     int set = tolua_toboolean(L, 3, 1);
 
@@ -336,8 +336,8 @@ static int tolua_region_set_flag(lua_State * L)
 
 static int tolua_region_get_resourcelevel(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
-    const char *type = tolua_tostring(L, 2, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
+    const char *type = tolua_tostring(L, 2, NULL);
     const resource_type *rtype = rt_find(type);
     if (rtype != NULL) {
         const rawmaterial *rm;
@@ -372,9 +372,9 @@ static int tolua_region_get_resource(lua_State * L)
     const resource_type *rtype;
     int result;
 
-    r = (region *)tolua_tousertype(L, 1, 0);
+    r = (region *)tolua_tousertype(L, 1, NULL);
     LUA_ASSERT(r != NULL, "invalid parameter");
-    type = tolua_tostring(L, 2, 0);
+    type = tolua_tostring(L, 2, NULL);
     LUA_ASSERT(type != NULL, "invalid parameter");
     
     result = special_resource(type);
@@ -403,8 +403,8 @@ static int tolua_region_get_resource(lua_State * L)
 
 static int tolua_region_set_resource(lua_State * L)
 {
-    region *r = (region *)tolua_tousertype(L, 1, 0);
-    const char *type = tolua_tostring(L, 2, 0);
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
+    const char *type = tolua_tostring(L, 2, NULL);
     int result, value = (int)tolua_tonumber(L, 3, 0);
     const resource_type *rtype;
 
@@ -429,7 +429,7 @@ static int tolua_region_set_resource(lua_State * L)
 
 static int tolua_region_destroy(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     remove_region(&regions, self);
     return 0;
 }
@@ -438,7 +438,7 @@ static int tolua_region_create(lua_State * L)
 {
     int x = (int)tolua_tonumber(L, 1, 0);
     int y = (int)tolua_tonumber(L, 2, 0);
-    const char *tname = tolua_tostring(L, 3, 0);
+    const char *tname = tolua_tostring(L, 3, NULL);
     if (tname) {
         plane *pl = findplane(x, y);
         const terrain_type *terrain = get_terrain(tname);
@@ -471,7 +471,7 @@ static int tolua_region_create(lua_State * L)
 
 static int tolua_region_get_units(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     unit **unit_ptr = (unit **)lua_newuserdata(L, sizeof(unit *));
 
     luaL_getmetatable(L, "unit");
@@ -485,7 +485,7 @@ static int tolua_region_get_units(lua_State * L)
 
 static int tolua_region_get_buildings(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     building **building_ptr =
         (building **)lua_newuserdata(L, sizeof(building *));
 
@@ -500,7 +500,7 @@ static int tolua_region_get_buildings(lua_State * L)
 
 static int tolua_region_get_ships(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     ship **ship_ptr = (ship **)lua_newuserdata(L, sizeof(ship *));
 
     luaL_getmetatable(L, "ship");
@@ -514,7 +514,7 @@ static int tolua_region_get_ships(lua_State * L)
 
 static int tolua_region_get_age(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
 
     if (self) {
         lua_pushinteger(L, self->age);
@@ -525,7 +525,7 @@ static int tolua_region_get_age(lua_State * L)
 
 static int tolua_region_get_peasants(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
 
     if (self) {
         lua_pushinteger(L, self->land ? self->land->peasants : 0);
@@ -536,7 +536,7 @@ static int tolua_region_get_peasants(lua_State * L)
 
 static int tolua_region_set_peasants(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
 
     if (self && self->land) {
         self->land->peasants = lua_tointeger(L, 2);
@@ -546,37 +546,22 @@ static int tolua_region_set_peasants(lua_State * L)
 
 static int tolua_region_getkey(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
-    const char *name = tolua_tostring(L, 2, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
+    const char *name = tolua_tostring(L, 2, NULL);
     int flag = atoi36(name);
-
-    lua_pushboolean(L, key_get(self->attribs, flag));
-    return 1;
-}
-
-static int tolua_region_getastral(lua_State * L)
-{
-    region *r = (region *)tolua_tousertype(L, 1, 0);
-    region *rt = r_standard_to_astral(r);
-
-    if (!rt) {
-        const char *tname = tolua_tostring(L, 2, 0);
-        plane *pl = get_astralplane();
-        rt = new_region(real2tp(r->x), real2tp(r->y), pl, 0);
-        if (tname) {
-            const terrain_type *terrain = get_terrain(tname);
-            terraform_region(rt, terrain);
-        }
+    int value = key_get(self->attribs, flag);
+    if (value != 0) {
+        lua_pushinteger(L, value);
+        return 1;
     }
-    tolua_pushusertype(L, rt, TOLUA_CAST "region");
-    return 1;
+    return 0;
 }
 
 static int tolua_region_setkey(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
-    const char *name = tolua_tostring(L, 2, 0);
-    int value = (int)tolua_tonumber(L, 3, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
+    const char *name = tolua_tostring(L, 2, NULL);
+    int value = (int)tolua_tonumber(L, 3, 1);
     int flag = atoi36(name);
 
     if (value) {
@@ -588,9 +573,27 @@ static int tolua_region_setkey(lua_State * L)
     return 0;
 }
 
+static int tolua_region_getastral(lua_State * L)
+{
+    region *r = (region *)tolua_tousertype(L, 1, NULL);
+    region *rt = r_standard_to_astral(r);
+
+    if (!rt) {
+        const char *tname = tolua_tostring(L, 2, NULL);
+        plane *pl = get_astralplane();
+        rt = new_region(real2tp(r->x), real2tp(r->y), pl, 0);
+        if (tname) {
+            const terrain_type *terrain = get_terrain(tname);
+            terraform_region(rt, terrain);
+        }
+    }
+    tolua_pushusertype(L, rt, TOLUA_CAST "region");
+    return 1;
+}
+
 static int tolua_region_tostring(lua_State * L)
 {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
     lua_pushstring(L, regionname(self, NULL));
     return 1;
 }
@@ -606,7 +609,7 @@ static int tolua_plane_get(lua_State * L)
 
 static int tolua_plane_erase(lua_State *L)
 {
-    plane *self = (plane *)tolua_tousertype(L, 1, 0);
+    plane *self = (plane *)tolua_tousertype(L, 1, NULL);
     remove_plane(self);
     return 0;
 }
@@ -618,7 +621,7 @@ static int tolua_plane_create(lua_State * L)
     int y = (int)tolua_tonumber(L, 3, 0);
     int width = (int)tolua_tonumber(L, 4, 0);
     int height = (int)tolua_tonumber(L, 5, 0);
-    const char *name = tolua_tostring(L, 6, 0);
+    const char *name = tolua_tostring(L, 6, NULL);
     plane *pl;
 
     pl = create_new_plane(id, name, x, x + width - 1, y, y + height - 1, 0);
@@ -629,15 +632,15 @@ static int tolua_plane_create(lua_State * L)
 
 static int tolua_plane_get_name(lua_State * L)
 {
-    plane *self = (plane *)tolua_tousertype(L, 1, 0);
+    plane *self = (plane *)tolua_tousertype(L, 1, NULL);
     tolua_pushstring(L, self->name);
     return 1;
 }
 
 static int tolua_plane_set_name(lua_State * L)
 {
-    plane *self = (plane *)tolua_tousertype(L, 1, 0);
-    const char *str = tolua_tostring(L, 2, 0);
+    plane *self = (plane *)tolua_tousertype(L, 1, NULL);
+    const char *str = tolua_tostring(L, 2, NULL);
     free(self->name);
     if (str)
         self->name = str_strdup(str);
@@ -648,14 +651,14 @@ static int tolua_plane_set_name(lua_State * L)
 
 static int tolua_plane_get_id(lua_State * L)
 {
-    plane *self = (plane *)tolua_tousertype(L, 1, 0);
+    plane *self = (plane *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, self->id);
     return 1;
 }
 
 static int tolua_plane_normalize(lua_State * L)
 {
-    plane *self = (plane *)tolua_tousertype(L, 1, 0);
+    plane *self = (plane *)tolua_tousertype(L, 1, NULL);
     int x = (int)tolua_tonumber(L, 2, 0);
     int y = (int)tolua_tonumber(L, 3, 0);
     pnormalize(&x, &y, self);
@@ -666,14 +669,14 @@ static int tolua_plane_normalize(lua_State * L)
 
 static int tolua_plane_tostring(lua_State * L)
 {
-    plane *self = (plane *)tolua_tousertype(L, 1, 0);
+    plane *self = (plane *)tolua_tousertype(L, 1, NULL);
     lua_pushstring(L, self->name);
     return 1;
 }
 
 static int tolua_plane_get_size(lua_State * L)
 {
-    plane *pl = (plane *)tolua_tousertype(L, 1, 0);
+    plane *pl = (plane *)tolua_tousertype(L, 1, NULL);
     lua_pushinteger(L, plane_width(pl));
     lua_pushinteger(L, plane_height(pl));
     return 2;
@@ -698,8 +701,8 @@ static int tolua_distance(lua_State * L)
 }
 
 static int tolua_region_get_curse(lua_State *L) {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
-    const char *name = tolua_tostring(L, 2, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
+    const char *name = tolua_tostring(L, 2, NULL);
     if (self->attribs) {
         curse * c = get_curse(self->attribs, ct_find(name));
         if (c) {
@@ -711,8 +714,8 @@ static int tolua_region_get_curse(lua_State *L) {
 }
 
 static int tolua_region_has_attrib(lua_State *L) {
-    region *self = (region *)tolua_tousertype(L, 1, 0);
-    const char *name = tolua_tostring(L, 2, 0);
+    region *self = (region *)tolua_tousertype(L, 1, NULL);
+    const char *name = tolua_tostring(L, 2, NULL);
     attrib * a = a_find(self->attribs, at_find(name));
     lua_pushboolean(L, a != NULL);
     return 1;
diff --git a/src/helpers.c b/src/helpers.c
index 223089c9c..7f19a6dcc 100644
--- a/src/helpers.c
+++ b/src/helpers.c
@@ -178,7 +178,7 @@ static bool lua_equipunit(unit *u, const char *eqname, int mask) {
             lua_pop(L, 1);
         }
         else {
-            result = (bool)lua_toboolean(L, -1);
+            result = lua_toboolean(L, -1) != 0;
             lua_pop(L, 1);
         }
     }
diff --git a/src/kernel/connection.c b/src/kernel/connection.c
index 7fc1213e0..995c276bb 100644
--- a/src/kernel/connection.c
+++ b/src/kernel/connection.c
@@ -263,7 +263,7 @@ bool b_blocknone(const connection * b, const unit * u, const region * r)
 
 bool b_rvisible(const connection * b, const region * r)
 {
-    return (bool)(b->to == r || b->from == r);
+    return (b->to == r || b->from == r);
 }
 
 bool b_fvisible(const connection * b, const struct faction * f,
@@ -412,7 +412,7 @@ b_blockfogwall(const connection * b, const unit * u, const region * r)
     UNUSED_ARG(b);
     if (!u)
         return true;
-    return (bool)(effskill(u, SK_PERCEPTION, r) > 4);    /* Das ist die alte Nebelwand */
+    return (effskill(u, SK_PERCEPTION, r) > 4);    /* Das ist die alte Nebelwand */
 }
 
 /** Legacy type used in old Eressea games, no longer in use. */
diff --git a/src/magic.c b/src/magic.c
index 342eb0831..469361c51 100644
--- a/src/magic.c
+++ b/src/magic.c
@@ -1213,7 +1213,7 @@ target_resists_magic(unit * magician, void *obj, int objtyp, int t_bonus)
 
 bool is_magic_resistant(unit * magician, unit * target, int resist_bonus)
 {
-    return (bool)target_resists_magic(magician, target, TYP_UNIT,
+    return target_resists_magic(magician, target, TYP_UNIT,
         resist_bonus);
 }
 
diff --git a/src/market.c b/src/market.c
index 0bd2fd647..b954e2d35 100644
--- a/src/market.c
+++ b/src/market.c
@@ -71,7 +71,7 @@ attrib_type at_market = {
 
 bool markets_module(void)
 {
-    return (bool)config_get_int("modules.market", 0);
+    return config_get_int("modules.market", 0) != 0;
 }
 
 void do_markets(void)
diff --git a/src/move.c b/src/move.c
index 222588651..545883f8e 100644
--- a/src/move.c
+++ b/src/move.c
@@ -892,7 +892,7 @@ static void drifting_ships(region * r)
 
 static bool present(region * r, unit * u)
 {
-    return (bool)(u && u->region == r);
+    return (u && u->region == r);
 }
 
 static void caught_target(region * r, unit * u)
diff --git a/src/reports.c b/src/reports.c
index dbea67489..f93eea685 100644
--- a/src/reports.c
+++ b/src/reports.c
@@ -683,7 +683,7 @@ bufunit(const faction * f, const unit * u, seen_mode mode, char *buf,
     int i, dh;
     int getarnt = fval(u, UFL_ANON_FACTION);
     const char *pzTmp, *str;
-    bool isbattle = (bool)(mode == seen_battle);
+    bool isbattle = (mode == seen_battle);
     item *itm, *show = NULL;
     faction *fv;
     char *bufp = buf;
diff --git a/src/util/filereader.c b/src/util/filereader.c
index 5ead2166f..c4a3b56cc 100644
--- a/src/util/filereader.c
+++ b/src/util/filereader.c
@@ -58,8 +58,8 @@ static const char *getbuf_utf8(FILE * F)
         eatwhite(bp, &white);       /* decoding errors will get caught later on, don't have to check */
         bp += white;
 
-        comment = (bool)(comment && cont);
-        quote = (bool)(quote && cont);
+        comment = (comment && cont);
+        quote = (quote && cont);
 
         if (tail[1] == 0) {
             /* we read the maximum number of bytes! */