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implement __pairs for entity, entity_components, etc #256

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Merged
daid merged 2 commits into from
Jun 12, 2025
Merged

implement __pairs for entity, entity_components, etc #256

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8c8c679
implement __pairs for components
GinjaNinja32 Mar 28, 2025
5c4994e
implement __pairs for entity
GinjaNinja32 Apr 7, 2025
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58 changes: 57 additions & 1 deletion src/script/component.h
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,8 @@ template<typename T> class ComponentHandler
lua_setfield(L, -2, "__index");
lua_pushcfunction(L, luaNewIndex);
lua_setfield(L, -2, "__newindex");
lua_pushcfunction(L, luaPairs);
lua_setfield(L, -2, "__pairs");
lua_pushcfunction(L, [](lua_State* L) {
if (!array_count_func) luaL_error(L, "Tried to get length of component %s that has no array", component_name);
auto ptr = luaToComponent(L, -1);
Expand Down Expand Up @@ -93,6 +95,27 @@ template<typename T> class ComponentHandler
return 0;
});
lua_setfield(L, -2, "__newindex");
lua_pushcfunction(L, [](lua_State* L) {
IndexedComponent* icptr = static_cast<IndexedComponent*>(lua_touserdata(L, -1));
if (!icptr) return 0;
if (!icptr->entity) return 0;
auto ptr = icptr->entity.template getComponent<T>();
if (!ptr) return 0;
if (array_count_func(*ptr) <= icptr->index) return luaL_error(L, "Index out of range for pairs on component %s", component_name);

lua_newtable(L);
int tbl = lua_gettop(L);
for (auto mem : indexed_members) {
mem.second.getter(L, ptr, icptr->index);
lua_setfield(L, tbl, mem.first.c_str());
}
lua_settop(L, tbl);
lua_getglobal(L, "next");
lua_rotate(L, 2, -1);
lua_pushnil(L);
return 3; // next, tbl, nil
});
lua_setfield(L, -2, "__pairs");
lua_pushstring(L, "sandboxed");
lua_setfield(L, -2, "__metatable");
lua_pop(L, 1);
Expand Down Expand Up @@ -163,6 +186,39 @@ template<typename T> class ComponentHandler
return 0;
}

static int luaPairs(lua_State* L) {
auto eptr = lua_touserdata(L, -1);
if (!eptr) return 0;
auto e = *static_cast<ecs::Entity*>(eptr);
if (!e) return 0;
auto ptr = e.getComponent<T>();
if (!ptr) return 0;

lua_newtable(L);
int tbl = lua_gettop(L);
if (array_count_func) {
int count = array_count_func(*ptr);
for (int i = 0; i < count; i++) {
auto ic = static_cast<IndexedComponent*>(lua_newuserdata(L, sizeof(IndexedComponent)));
ic->entity = e;
ic->index = i;
luaL_getmetatable(L, array_metatable_name.c_str());
lua_setmetatable(L, -2);
lua_seti(L, tbl, i + 1);
}
}
for (auto mem : members) {
mem.second.getter(L, ptr);
lua_setfield(L, tbl, mem.first.c_str());
}

lua_settop(L, tbl);
lua_getglobal(L, "next");
lua_rotate(L, 2, -1);
lua_pushnil(L);
return 3; // next, tbl, nil
}

static T* luaToComponent(lua_State* L, int index) {
auto eptr = lua_touserdata(L, index);
if (!eptr) return nullptr;
Expand Down Expand Up @@ -236,4 +292,4 @@ template<typename T> class ComponentHandler

}

#endif//SP_SCRIPT_ENVIRONMENT
#endif//SP_SCRIPT_ENVIRONMENT
68 changes: 68 additions & 0 deletions src/script/environment.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -137,6 +137,47 @@ static int luaEntityNewIndex(lua_State* L) {
return 0;
}

static int luaEntityPairsNext(lua_State* L) {
lua_settop(L, 2); // ensure we have a (possibly nil) key, as we may have been called with just (entity)

auto e = Convert<ecs::Entity>::fromLua(L, 1);
if (!e) return 0;

if (lua_type(L, 2) == LUA_TNIL) {
// nil => first call; return components first
lua_pop(L, 1);
lua_pushstring(L, "components");
*static_cast<ecs::Entity*>(lua_newuserdata(L, sizeof(ecs::Entity))) = e;
luaL_getmetatable(L, "entity_components");
lua_setmetatable(L, -2);
return 2;
}
if (lua_type(L, 2) == LUA_TSTRING && !strcmp(lua_tostring(L, 2), "components")) {
// second call, give lua_next a nil to get the first LTC key.
// from the third call onwards, we'll pass the previous key directly to lua_next.
lua_pop(L, 1);
lua_pushnil(L);
}

auto ltc = e.getComponent<LuaTableComponent>();
if (!ltc) return 0;

lua_rawgetp(L, LUA_REGISTRYINDEX, ltc);
lua_rotate(L, 2, -1);

return lua_next(L, -2) ? 2 : 0;
}

static int luaEntityPairs(lua_State* L) {
auto e = Convert<ecs::Entity>::fromLua(L, 1);
if (!e) return 0;

lua_pushcfunction(L, luaEntityPairsNext);
lua_pushvalue(L, -2);
lua_pushnil(L);
return 3;
}

static int luaEntityComponentsIndex(lua_State* L) {
auto eptr = lua_touserdata(L, -2);
if (!eptr) return 0;
Expand Down Expand Up @@ -165,6 +206,29 @@ static int luaEntityComponentsNewIndex(lua_State* L) {
return luaL_error(L, "Tried to set non-exsisting component %s", key);
}

static int luaEntityComponentsPairs(lua_State* L) {
auto eptr = lua_touserdata(L, -1);
if (!eptr) return 0;
auto e = *static_cast<ecs::Entity*>(eptr);
if (!e) return 0;

lua_newtable(L);
int tbl = lua_gettop(L);

for (auto entry : ComponentRegistry::components) {
int n = entry.second.getter(L, e, entry.first.c_str());
if (n == 1) {
lua_setfield(L, tbl, entry.first.c_str());
}
}

lua_settop(L, tbl);
lua_getglobal(L, "next");
lua_rotate(L, 2, -1);
lua_pushnil(L);
return 3; // next, tbl, nil
}

static int luaEntityEqual(lua_State* L) {
auto e1 = Convert<ecs::Entity>::fromLua(L, -2);
if (!e1) return 0;
Expand Down Expand Up @@ -209,6 +273,8 @@ lua_State* Environment::getLuaState()
lua_setfield(L, -2, "__index");
lua_pushcfunction(L, luaEntityNewIndex);
lua_setfield(L, -2, "__newindex");
lua_pushcfunction(L, luaEntityPairs);
lua_setfield(L, -2, "__pairs");
lua_pushcfunction(L, luaEntityEqual);
lua_setfield(L, -2, "__eq");
lua_pushstring(L, "sandboxed");
Expand All @@ -221,6 +287,8 @@ lua_State* Environment::getLuaState()
lua_setfield(L, -2, "__index");
lua_pushcfunction(L, luaEntityComponentsNewIndex);
lua_setfield(L, -2, "__newindex");
lua_pushcfunction(L, luaEntityComponentsPairs);
lua_setfield(L, -2, "__pairs");
lua_pushstring(L, "sandboxed");
lua_setfield(L, -2, "__metatable");
lua_pop(L, 1);
Expand Down
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