Removed a crash bug when the lambdas are absent

rsc/startup.lua

@@ -6,7 +6,9 @@ pager = ...
 
 ---[[
 
---BUG: RegionPagerLua fails without these
+--DOCS: These lambdas should return true or false, depending on if the operation succeeded or not
+--DOCS: No return value given is recognized as a failure
+--DOCS: OnCreate() and OnUnload() return values are currently ignored
 region_pager.SetOnLoad(pager, function(r)
 	print("Calling SetOnLoad's lambda")
 end)

src/application.cpp

@@ -119,9 +119,6 @@ void Application::Quit() {
 	BaseScene::SetRenderer(nullptr);
 	SDL_DestroyRenderer(renderer);
 	SDL_DestroyWindow(window);
-
-	//TODO: is this necessary?
-//	SDL_Quit();
 }
 
 //-------------------------

src/libmap/region_pager_api.cpp

@@ -104,8 +104,6 @@ static int unloadRegion(lua_State* L) {
 	return 0;
 }
 
-//TODO: (1) check that parameters are not null
-
 static int setOnLoad(lua_State* L) {
 	RegionPagerLua* pager = reinterpret_cast<RegionPagerLua*>(lua_touserdata(L, 1));
 	luaL_unref(L, LUA_REGISTRYINDEX, pager->GetLoadReference());

src/libmap/region_pager_base.cpp

@@ -28,8 +28,6 @@ RegionPagerBase::~RegionPagerBase() {
 	UnloadAll();
 };
 
-//TODO: (1) add nullptr checks to the calls to GetRegion()
-
 Region::type_t RegionPagerBase::SetTile(int x, int y, int z, Region::type_t v) {
 	Region* ptr = GetRegion(x, y);
 	return ptr->SetTile(x - ptr->GetX(), y - ptr->GetY(), z, v);

src/libmap/region_pager_lua.cpp

@@ -23,9 +23,6 @@
 
 #include <stdexcept>
 
-//DOCS: Load, Save and Create fail unless the lua function has been set
-//DOCS: UnloadIf and UnloadAll will still continue without the function set
-
 RegionPagerLua::~RegionPagerLua() {
 	//unload all regions
 	UnloadAll();
@@ -44,6 +41,7 @@ Region* RegionPagerLua::LoadRegion(int x, int y) {
 	//check if this function is available
 	if (lua_isnil(lua, -1)) {
 		lua_pop(lua, 1);
+		//signal that there is no load function
 		return nullptr;
 	}
 
@@ -57,17 +55,20 @@ Region* RegionPagerLua::LoadRegion(int x, int y) {
 	}
 
 	//check the return value, success or failure
-	if (lua_toboolean(lua, -1)) {
+	if (lua_isboolean(lua, -1) && lua_toboolean(lua, -1)) {
 		lua_pop(lua, 1);
+		//push and return the loaded region
 		regionList.push_front(tmpRegion);
 		return &regionList.front();
 	}
 	else {
 		lua_pop(lua, 1);
+		//signal a failure
 		return nullptr;
 	}
 }
 
+//NOTE: this return value seems strange; could replace it with a boolean
 //return the saved region, or nullptr on failure
 Region* RegionPagerLua::SaveRegion(int x, int y) {
 	//get the pager's function from the registry
@@ -76,6 +77,7 @@ Region* RegionPagerLua::SaveRegion(int x, int y) {
 	//check if this function is available
 	if (lua_isnil(lua, -1)) {
 		lua_pop(lua, 1);
+		//signal that the region wasn't saved
 		return nullptr;
 	}
 
@@ -83,6 +85,7 @@ Region* RegionPagerLua::SaveRegion(int x, int y) {
 	Region* ptr = FindRegion(x, y);
 	if (!ptr) {
 		lua_pop(lua, 1);
+		//signal that there is no save function
 		return nullptr;
 	}
 	lua_pushlightuserdata(lua, ptr);
@@ -93,17 +96,20 @@ Region* RegionPagerLua::SaveRegion(int x, int y) {
 	}
 
 	//check the return value, success or failure
-	if (lua_toboolean(lua, -1)) {
+	if (lua_isboolean(lua, -1) && lua_toboolean(lua, -1)) {
 		lua_pop(lua, 1);
+		//return the specified region that was saved
 		return ptr;
 	}
 	else {
 		lua_pop(lua, 1);
+		//signal a failure
 		return nullptr;
 	}
 }
 
-//return the created region, or nullptr on failure
+//DOCS: since this method is the last ditch call from GetRegion, it must return a valid region object, even if the create function hasn't been set.
+//return a new region, throwing an error on failure
 Region* RegionPagerLua::CreateRegion(int x, int y) {
 	if (FindRegion(x, y)) {
 		throw(std::logic_error("Cannot overwrite an existing region"));
@@ -115,7 +121,9 @@ Region* RegionPagerLua::CreateRegion(int x, int y) {
 	//check if this function is available
 	if (lua_isnil(lua, -1)) {
 		lua_pop(lua, 1);
-		return nullptr;
+		//return an empty region object
+		regionList.emplace_front(x, y);
+		return &regionList.front();
 	}
 
 	//something to work on

src/libmap/region_pager_lua.hpp

@@ -28,7 +28,7 @@
 #include <functional>
 #include <string>
 
-//NOTE: set the lua hook before use
+//DOCS: set the lua hook before use
 
 class RegionPagerLua : public RegionPagerBase {
 public:

src/main.cpp

@@ -27,6 +27,7 @@
 #include <stdexcept>
 
 int main(int argc, char** argv) {
+	std::cout << "Beginning " << argv[0] << std::endl;
 	try {
 		Application app;
 		app.Init(argc, argv);
@@ -37,5 +38,6 @@ int main(int argc, char** argv) {
 		std::cerr << "Fatal Error: " << e.what() << std::endl;
 		return 1;
 	}
+	std::cout << "Clean exit from " << argv[0] << std::endl;
 	return 0;
 }