Codechange: Use null pointer literal instead of the NULL macro

48 files changed, 191 insertions, 191 deletions

diff --git a/src/script/api/script_basestation.cpp b/src/script/api/script_basestation.cpp
index 229abf865..c51fa867a 100644
--- a/src/script/api/script_basestation.cpp
+++ b/src/script/api/script_basestation.cpp
@@ -22,12 +22,12 @@
 /* static */ bool ScriptBaseStation::IsValidBaseStation(StationID station_id)
 {
 	const BaseStation *st = ::BaseStation::GetIfValid(station_id);
-	return st != NULL && (st->owner == ScriptObject::GetCompany() || ScriptObject::GetCompany() == OWNER_DEITY || st->owner == OWNER_NONE);
+	return st != nullptr && (st->owner == ScriptObject::GetCompany() || ScriptObject::GetCompany() == OWNER_DEITY || st->owner == OWNER_NONE);
 }
 
 /* static */ char *ScriptBaseStation::GetName(StationID station_id)
 {
-	if (!IsValidBaseStation(station_id)) return NULL;
+	if (!IsValidBaseStation(station_id)) return nullptr;
 
 	::SetDParam(0, station_id);
 	return GetString(::Station::IsValidID(station_id) ? STR_STATION_NAME : STR_WAYPOINT_NAME);
@@ -39,7 +39,7 @@
 
 	EnforcePrecondition(false, ScriptObject::GetCompany() != OWNER_DEITY);
 	EnforcePrecondition(false, IsValidBaseStation(station_id));
-	EnforcePrecondition(false, name != NULL);
+	EnforcePrecondition(false, name != nullptr);
 	const char *text = name->GetDecodedText();
 	EnforcePreconditionEncodedText(false, text);
 	EnforcePreconditionCustomError(false, ::Utf8StringLength(text) < MAX_LENGTH_STATION_NAME_CHARS, ScriptError::ERR_PRECONDITION_STRING_TOO_LONG);
diff --git a/src/script/api/script_basestation.hpp b/src/script/api/script_basestation.hpp
index 9676829f6..5bfd9ac84 100644
--- a/src/script/api/script_basestation.hpp
+++ b/src/script/api/script_basestation.hpp
@@ -52,7 +52,7 @@ public:
 	 * @param station_id The basestation to set the name of.
 	 * @param name The new name of the station (can be either a raw string, or a ScriptText object).
 	 * @pre IsValidBaseStation(station_id).
-	 * @pre name != NULL && len(name) != 0.
+	 * @pre name != nullptr && len(name) != 0.
 	 * @game @pre Valid ScriptCompanyMode active in scope.
 	 * @exception ScriptError::ERR_NAME_IS_NOT_UNIQUE
 	 * @return True if the name was changed.
diff --git a/src/script/api/script_bridge.cpp b/src/script/api/script_bridge.cpp
index f532f11b7..03787be2a 100644
--- a/src/script/api/script_bridge.cpp
+++ b/src/script/api/script_bridge.cpp
@@ -102,7 +102,7 @@ static void _DoCommandReturnBuildBridge1(class ScriptInstance *instance)
 
 	ScriptObject::SetCallbackVariable(0, start);
 	ScriptObject::SetCallbackVariable(1, end);
-	return ScriptObject::DoCommand(end, start, type | bridge_id, CMD_BUILD_BRIDGE, NULL, &::_DoCommandReturnBuildBridge1);
+	return ScriptObject::DoCommand(end, start, type | bridge_id, CMD_BUILD_BRIDGE, nullptr, &::_DoCommandReturnBuildBridge1);
 }
 
 /* static */ bool ScriptBridge::_BuildBridgeRoad1()
@@ -114,7 +114,7 @@ static void _DoCommandReturnBuildBridge1(class ScriptInstance *instance)
 	DiagDirection dir_1 = ::DiagdirBetweenTiles(end, start);
 	DiagDirection dir_2 = ::ReverseDiagDir(dir_1);
 
-	return ScriptObject::DoCommand(start + ::TileOffsByDiagDir(dir_1), ::DiagDirToRoadBits(dir_2) | (ScriptObject::GetRoadType() << 4), 0, CMD_BUILD_ROAD, NULL, &::_DoCommandReturnBuildBridge2);
+	return ScriptObject::DoCommand(start + ::TileOffsByDiagDir(dir_1), ::DiagDirToRoadBits(dir_2) | (ScriptObject::GetRoadType() << 4), 0, CMD_BUILD_ROAD, nullptr, &::_DoCommandReturnBuildBridge2);
 }
 
 /* static */ bool ScriptBridge::_BuildBridgeRoad2()
@@ -138,8 +138,8 @@ static void _DoCommandReturnBuildBridge1(class ScriptInstance *instance)
 
 /* static */ char *ScriptBridge::GetName(BridgeID bridge_id, ScriptVehicle::VehicleType vehicle_type)
 {
-	EnforcePrecondition(NULL, vehicle_type == ScriptVehicle::VT_ROAD || vehicle_type == ScriptVehicle::VT_RAIL || vehicle_type == ScriptVehicle::VT_WATER);
-	if (!IsValidBridge(bridge_id)) return NULL;
+	EnforcePrecondition(nullptr, vehicle_type == ScriptVehicle::VT_ROAD || vehicle_type == ScriptVehicle::VT_RAIL || vehicle_type == ScriptVehicle::VT_WATER);
+	if (!IsValidBridge(bridge_id)) return nullptr;
 
 	return GetString(vehicle_type == ScriptVehicle::VT_WATER ? STR_LAI_BRIDGE_DESCRIPTION_AQUEDUCT : ::GetBridgeSpec(bridge_id)->transport_name[vehicle_type]);
 }
diff --git a/src/script/api/script_cargo.cpp b/src/script/api/script_cargo.cpp
index a2643f897..9e83daa08 100644
--- a/src/script/api/script_cargo.cpp
+++ b/src/script/api/script_cargo.cpp
@@ -29,7 +29,7 @@
 
 /* static */ char *ScriptCargo::GetCargoLabel(CargoID cargo_type)
 {
-	if (!IsValidCargo(cargo_type)) return NULL;
+	if (!IsValidCargo(cargo_type)) return nullptr;
 	const CargoSpec *cargo = ::CargoSpec::Get(cargo_type);
 
 	/* cargo->label is a uint32 packing a 4 character non-terminated string,
diff --git a/src/script/api/script_client.cpp b/src/script/api/script_client.cpp
index 855ad86a0..247cac98c 100644
--- a/src/script/api/script_client.cpp
+++ b/src/script/api/script_client.cpp
@@ -20,37 +20,37 @@
  * Finds NetworkClientInfo given client-identifier,
  *  is used by other methods to resolve client-identifier.
  * @param client The client to get info structure for
- * @return A pointer to corresponding CI struct or NULL when not found.
+ * @return A pointer to corresponding CI struct or nullptr when not found.
  */
 static NetworkClientInfo *FindClientInfo(ScriptClient::ClientID client)
 {
-	if (client == ScriptClient::CLIENT_INVALID) return NULL;
-	if (!_networking) return NULL;
+	if (client == ScriptClient::CLIENT_INVALID) return nullptr;
+	if (!_networking) return nullptr;
 	return NetworkClientInfo::GetByClientID((::ClientID)client);
 }
 
 /* static */ ScriptClient::ClientID ScriptClient::ResolveClientID(ScriptClient::ClientID client)
 {
-	return (FindClientInfo(client) == NULL ? ScriptClient::CLIENT_INVALID : client);
+	return (FindClientInfo(client) == nullptr ? ScriptClient::CLIENT_INVALID : client);
 }
 
 /* static */ char *ScriptClient::GetName(ScriptClient::ClientID client)
 {
 	NetworkClientInfo *ci = FindClientInfo(client);
-	if (ci == NULL) return NULL;
+	if (ci == nullptr) return nullptr;
 	return stredup(ci->client_name);
 }
 
 /* static */ ScriptCompany::CompanyID ScriptClient::GetCompany(ScriptClient::ClientID client)
 {
 	NetworkClientInfo *ci = FindClientInfo(client);
-	if (ci == NULL) return ScriptCompany::COMPANY_INVALID;
+	if (ci == nullptr) return ScriptCompany::COMPANY_INVALID;
 	return (ScriptCompany::CompanyID)ci->client_playas;
 }
 
 /* static */ ScriptDate::Date ScriptClient::GetJoinDate(ScriptClient::ClientID client)
 {
 	NetworkClientInfo *ci = FindClientInfo(client);
-	if (ci == NULL) return ScriptDate::DATE_INVALID;
+	if (ci == nullptr) return ScriptDate::DATE_INVALID;
 	return (ScriptDate::Date)ci->join_date;
 }
diff --git a/src/script/api/script_company.cpp b/src/script/api/script_company.cpp
index 54888c33c..59f4fa43e 100644
--- a/src/script/api/script_company.cpp
+++ b/src/script/api/script_company.cpp
@@ -45,7 +45,7 @@
 {
 	CCountedPtr<Text> counter(name);
 
-	EnforcePrecondition(false, name != NULL);
+	EnforcePrecondition(false, name != nullptr);
 	const char *text = name->GetDecodedText();
 	EnforcePreconditionEncodedText(false, text);
 	EnforcePreconditionCustomError(false, ::Utf8StringLength(text) < MAX_LENGTH_COMPANY_NAME_CHARS, ScriptError::ERR_PRECONDITION_STRING_TOO_LONG);
@@ -56,7 +56,7 @@
 /* static */ char *ScriptCompany::GetName(ScriptCompany::CompanyID company)
 {
 	company = ResolveCompanyID(company);
-	if (company == COMPANY_INVALID) return NULL;
+	if (company == COMPANY_INVALID) return nullptr;
 
 	::SetDParam(0, company);
 	return GetString(STR_COMPANY_NAME);
@@ -66,7 +66,7 @@
 {
 	CCountedPtr<Text> counter(name);
 
-	EnforcePrecondition(false, name != NULL);
+	EnforcePrecondition(false, name != nullptr);
 	const char *text = name->GetDecodedText();
 	EnforcePreconditionEncodedText(false, text);
 	EnforcePreconditionCustomError(false, ::Utf8StringLength(text) < MAX_LENGTH_PRESIDENT_NAME_CHARS, ScriptError::ERR_PRECONDITION_STRING_TOO_LONG);
@@ -312,7 +312,7 @@
 	if ((::LiveryScheme)scheme < LS_BEGIN || (::LiveryScheme)scheme >= LS_END) return COLOUR_INVALID;
 
 	const Company *c = ::Company::GetIfValid(_current_company);
-	if (c == NULL) return COLOUR_INVALID;
+	if (c == nullptr) return COLOUR_INVALID;
 
 	return (ScriptCompany::Colours)c->livery[scheme].colour1;
 }
@@ -322,7 +322,7 @@
 	if ((::LiveryScheme)scheme < LS_BEGIN || (::LiveryScheme)scheme >= LS_END) return COLOUR_INVALID;
 
 	const Company *c = ::Company::GetIfValid(_current_company);
-	if (c == NULL) return COLOUR_INVALID;
+	if (c == nullptr) return COLOUR_INVALID;
 
 	return (ScriptCompany::Colours)c->livery[scheme].colour2;
 }
diff --git a/src/script/api/script_company.hpp b/src/script/api/script_company.hpp
index 55cb7a930..e3be24e55 100644
--- a/src/script/api/script_company.hpp
+++ b/src/script/api/script_company.hpp
@@ -139,7 +139,7 @@ public:
 	/**
 	 * Set the name of your company.
 	 * @param name The new name of the company (can be either a raw string, or a ScriptText object).
-	 * @pre name != NULL && len(name) != 0.
+	 * @pre name != nullptr && len(name) != 0.
 	 * @exception ScriptError::ERR_NAME_IS_NOT_UNIQUE
 	 * @return True if the name was changed.
 	 */
@@ -156,7 +156,7 @@ public:
 	/**
 	 * Set the name of your president.
 	 * @param name The new name of the president (can be either a raw string, or a ScriptText object).
-	 * @pre name != NULL && len(name) != 0.
+	 * @pre name != nullptr && len(name) != 0.
 	 * @exception ScriptError::ERR_NAME_IS_NOT_UNIQUE
 	 * @return True if the name was changed.
 	 */
diff --git a/src/script/api/script_controller.cpp b/src/script/api/script_controller.cpp
index a42c8ede9..beb9b155f 100644
--- a/src/script/api/script_controller.cpp
+++ b/src/script/api/script_controller.cpp
@@ -43,7 +43,7 @@
 		ticks = 1;
 	}
 
-	throw Script_Suspend(ticks, NULL);
+	throw Script_Suspend(ticks, nullptr);
 }
 
 /* static */ void ScriptController::Break(const char* message)
@@ -119,7 +119,7 @@ ScriptController::~ScriptController()
 	strtolower(library_name);
 
 	ScriptInfo *lib = ScriptObject::GetActiveInstance()->FindLibrary(library, version);
-	if (lib == NULL) {
+	if (lib == nullptr) {
 		char error[1024];
 		seprintf(error, lastof(error), "couldn't find library '%s' with version %d", library, version);
 		throw sq_throwerror(vm, error);
diff --git a/src/script/api/script_engine.cpp b/src/script/api/script_engine.cpp
index c564cee97..dfd15bee4 100644
--- a/src/script/api/script_engine.cpp
+++ b/src/script/api/script_engine.cpp
@@ -25,7 +25,7 @@
 /* static */ bool ScriptEngine::IsValidEngine(EngineID engine_id)
 {
 	const Engine *e = ::Engine::GetIfValid(engine_id);
-	if (e == NULL || !e->IsEnabled()) return false;
+	if (e == nullptr || !e->IsEnabled()) return false;
 
 	/* AIs have only access to engines they can purchase or still have in use.
 	 * Deity has access to all engined that will be or were available ever. */
@@ -36,12 +36,12 @@
 /* static */ bool ScriptEngine::IsBuildable(EngineID engine_id)
 {
 	const Engine *e = ::Engine::GetIfValid(engine_id);
-	return e != NULL && ::IsEngineBuildable(engine_id, e->type, ScriptObject::GetCompany());
+	return e != nullptr && ::IsEngineBuildable(engine_id, e->type, ScriptObject::GetCompany());
 }
 
 /* static */ char *ScriptEngine::GetName(EngineID engine_id)
 {
-	if (!IsValidEngine(engine_id)) return NULL;
+	if (!IsValidEngine(engine_id)) return nullptr;
 
 	::SetDParam(0, engine_id);
 	return GetString(STR_ENGINE_NAME);
diff --git a/src/script/api/script_error.hpp b/src/script/api/script_error.hpp
index 1817cdb7d..346298d2c 100644
--- a/src/script/api/script_error.hpp
+++ b/src/script/api/script_error.hpp
@@ -44,7 +44,7 @@
  * @param string The string that is checked.
  */
 #define EnforcePreconditionEncodedText(returnval, string)   \
-	if ((string) == NULL) { \
+	if ((string) == nullptr) { \
 		ScriptObject::SetLastError(ScriptError::ERR_PRECONDITION_TOO_MANY_PARAMETERS); \
 		return returnval; \
 	} \
diff --git a/src/script/api/script_event.cpp b/src/script/api/script_event.cpp
index 0e711ca41..2d364e8d2 100644
--- a/src/script/api/script_event.cpp
+++ b/src/script/api/script_event.cpp
@@ -23,7 +23,7 @@ struct ScriptEventData {
 
 /* static */ void ScriptEventController::CreateEventPointer()
 {
-	assert(ScriptObject::GetEventPointer() == NULL);
+	assert(ScriptObject::GetEventPointer() == nullptr);
 
 	ScriptObject::GetEventPointer() = new ScriptEventData();
 }
@@ -45,7 +45,7 @@ struct ScriptEventData {
 
 /* static */ bool ScriptEventController::IsEventWaiting()
 {
-	if (ScriptObject::GetEventPointer() == NULL) ScriptEventController::CreateEventPointer();
+	if (ScriptObject::GetEventPointer() == nullptr) ScriptEventController::CreateEventPointer();
 	ScriptEventData *data = (ScriptEventData *)ScriptObject::GetEventPointer();
 
 	return !data->stack.empty();
@@ -53,10 +53,10 @@ struct ScriptEventData {
 
 /* static */ ScriptEvent *ScriptEventController::GetNextEvent()
 {
-	if (ScriptObject::GetEventPointer() == NULL) ScriptEventController::CreateEventPointer();
+	if (ScriptObject::GetEventPointer() == nullptr) ScriptEventController::CreateEventPointer();
 	ScriptEventData *data = (ScriptEventData *)ScriptObject::GetEventPointer();
 
-	if (data->stack.empty()) return NULL;
+	if (data->stack.empty()) return nullptr;
 
 	ScriptEvent *e = data->stack.front();
 	data->stack.pop();
@@ -65,7 +65,7 @@ struct ScriptEventData {
 
 /* static */ void ScriptEventController::InsertEvent(ScriptEvent *event)
 {
-	if (ScriptObject::GetEventPointer() == NULL) ScriptEventController::CreateEventPointer();
+	if (ScriptObject::GetEventPointer() == nullptr) ScriptEventController::CreateEventPointer();
 	ScriptEventData *data = (ScriptEventData *)ScriptObject::GetEventPointer();
 
 	event->AddRef();
diff --git a/src/script/api/script_event_types.cpp b/src/script/api/script_event_types.cpp
index d424e6fef..e997f2320 100644
--- a/src/script/api/script_event_types.cpp
+++ b/src/script/api/script_event_types.cpp
@@ -25,12 +25,12 @@
 bool ScriptEventEnginePreview::IsEngineValid() const
 {
 	const Engine *e = ::Engine::GetIfValid(this->engine);
-	return e != NULL && e->IsEnabled();
+	return e != nullptr && e->IsEnabled();
 }
 
 char *ScriptEventEnginePreview::GetName()
 {
-	if (!this->IsEngineValid()) return NULL;
+	if (!this->IsEngineValid()) return nullptr;
 
 	::SetDParam(0, this->engine);
 	return GetString(STR_ENGINE_NAME);
@@ -132,13 +132,13 @@ ScriptEventAdminPort::~ScriptEventAdminPort()
 }
 
 #define SKIP_EMPTY(p) while (*(p) == ' ' || *(p) == '\n' || *(p) == '\r') (p)++;
-#define RETURN_ERROR(stack) { ScriptLog::Error("Received invalid JSON data from AdminPort."); if (stack != 0) sq_pop(vm, stack); return NULL; }
+#define RETURN_ERROR(stack) { ScriptLog::Error("Received invalid JSON data from AdminPort."); if (stack != 0) sq_pop(vm, stack); return nullptr; }
 
 SQInteger ScriptEventAdminPort::GetObject(HSQUIRRELVM vm)
 {
 	char *p = this->json;
 
-	if (this->ReadTable(vm, p) == NULL) {
+	if (this->ReadTable(vm, p) == nullptr) {
 		sq_pushnull(vm);
 		return 1;
 	}
@@ -189,18 +189,18 @@ char *ScriptEventAdminPort::ReadTable(HSQUIRRELVM vm, char *p)
 		if (*p++ != '"') RETURN_ERROR(1);
 
 		p = ReadString(vm, p);
-		if (p == NULL) {
+		if (p == nullptr) {
 			sq_pop(vm, 1);
-			return NULL;
+			return nullptr;
 		}
 
 		SKIP_EMPTY(p);
 		if (*p++ != ':') RETURN_ERROR(2);
 
 		p = this->ReadValue(vm, p);
-		if (p == NULL) {
+		if (p == nullptr) {
 			sq_pop(vm, 2);
-			return NULL;
+			return nullptr;
 		}
 
 		sq_rawset(vm, -3);
@@ -241,7 +241,7 @@ char *ScriptEventAdminPort::ReadValue(HSQUIRRELVM vm, char *p)
 		case '"': {
 			/* String */
 			p = ReadString(vm, ++p);
-			if (p == NULL) return NULL;
+			if (p == nullptr) return nullptr;
 
 			break;
 		}
@@ -249,7 +249,7 @@ char *ScriptEventAdminPort::ReadValue(HSQUIRRELVM vm, char *p)
 		case '{': {
 			/* Table */
 			p = this->ReadTable(vm, p);
-			if (p == NULL) return NULL;
+			if (p == nullptr) return nullptr;
 
 			break;
 		}
@@ -268,9 +268,9 @@ char *ScriptEventAdminPort::ReadValue(HSQUIRRELVM vm, char *p)
 
 			while (*p++ != ']') {
 				p = this->ReadValue(vm, p);
-				if (p == NULL) {
+				if (p == nullptr) {
 					sq_pop(vm, 1);
-					return NULL;
+					return nullptr;
 				}
 				sq_arrayappend(vm, -2);
 
diff --git a/src/script/api/script_gamesettings.cpp b/src/script/api/script_gamesettings.cpp
index 1f8ded877..490e6eee0 100644
--- a/src/script/api/script_gamesettings.cpp
+++ b/src/script/api/script_gamesettings.cpp
@@ -21,7 +21,7 @@
 {
 	uint i;
 	const SettingDesc *sd = GetSettingFromName(setting, &i);
-	return sd != NULL && sd->desc.cmd != SDT_STRING;
+	return sd != nullptr && sd->desc.cmd != SDT_STRING;
 }
 
 /* static */ int32 ScriptGameSettings::GetValue(const char *setting)
diff --git a/src/script/api/script_goal.cpp b/src/script/api/script_goal.cpp
index 54312cd9d..b5f6ccef2 100644
--- a/src/script/api/script_goal.cpp
+++ b/src/script/api/script_goal.cpp
@@ -34,14 +34,14 @@
 	CCountedPtr<Text> counter(goal);
 
 	EnforcePrecondition(GOAL_INVALID, ScriptObject::GetCompany() == OWNER_DEITY);
-	EnforcePrecondition(GOAL_INVALID, goal != NULL);
+	EnforcePrecondition(GOAL_INVALID, goal != nullptr);
 	const char *text = goal->GetEncodedText();
 	EnforcePreconditionEncodedText(GOAL_INVALID, text);
 	EnforcePrecondition(GOAL_INVALID, company == ScriptCompany::COMPANY_INVALID || ScriptCompany::ResolveCompanyID(company) != ScriptCompany::COMPANY_INVALID);
 
 	uint8 c = company;
 	if (company == ScriptCompany::COMPANY_INVALID) c = INVALID_COMPANY;
-	StoryPage *story_page = NULL;
+	StoryPage *story_page = nullptr;
 	if (type == GT_STORY_PAGE && ScriptStoryPage::IsValidStoryPage((ScriptStoryPage::StoryPageID)destination)) story_page = ::StoryPage::Get((ScriptStoryPage::StoryPageID)destination);
 
 	EnforcePrecondition(GOAL_INVALID, (type == GT_NONE && destination == 0) ||
@@ -49,7 +49,7 @@
 			(type == GT_INDUSTRY && ScriptIndustry::IsValidIndustry(destination)) ||
 			(type == GT_TOWN && ScriptTown::IsValidTown(destination)) ||
 			(type == GT_COMPANY && ScriptCompany::ResolveCompanyID((ScriptCompany::CompanyID)destination) != ScriptCompany::COMPANY_INVALID) ||
-			(type == GT_STORY_PAGE && story_page != NULL && (c == INVALID_COMPANY ? story_page->company == INVALID_COMPANY : story_page->company == INVALID_COMPANY || story_page->company == c)));
+			(type == GT_STORY_PAGE && story_page != nullptr && (c == INVALID_COMPANY ? story_page->company == INVALID_COMPANY : story_page->company == INVALID_COMPANY || story_page->company == c)));
 
 	if (!ScriptObject::DoCommand(0, type | (c << 8), destination, CMD_CREATE_GOAL, text, &ScriptInstance::DoCommandReturnGoalID)) return GOAL_INVALID;
 
@@ -71,7 +71,7 @@
 
 	EnforcePrecondition(false, IsValidGoal(goal_id));
 	EnforcePrecondition(false, ScriptObject::GetCompany() == OWNER_DEITY);
-	EnforcePrecondition(false, goal != NULL);
+	EnforcePrecondition(false, goal != nullptr);
 	EnforcePrecondition(false, !StrEmpty(goal->GetEncodedText()));
 
 	return ScriptObject::DoCommand(0, goal_id, 0, CMD_SET_GOAL_TEXT, goal->GetEncodedText());
@@ -85,11 +85,11 @@
 	EnforcePrecondition(false, ScriptObject::GetCompany() == OWNER_DEITY);
 
 	/* Ensure null as used for emtpy string. */
-	if (progress != NULL && StrEmpty(progress->GetEncodedText())) {
-		progress = NULL;
+	if (progress != nullptr && StrEmpty(progress->GetEncodedText())) {
+		progress = nullptr;
 	}
 
-	return ScriptObject::DoCommand(0, goal_id, 0, CMD_SET_GOAL_PROGRESS, progress != NULL ? progress->GetEncodedText() : NULL);
+	return ScriptObject::DoCommand(0, goal_id, 0, CMD_SET_GOAL_PROGRESS, progress != nullptr ? progress->GetEncodedText() : nullptr);
 }
 
 /* static */ bool ScriptGoal::SetCompleted(GoalID goal_id, bool completed)
@@ -106,7 +106,7 @@
 	EnforcePrecondition(false, ScriptObject::GetCompany() == OWNER_DEITY);
 
 	Goal *g = Goal::Get(goal_id);
-	return g != NULL && g->completed;
+	return g != nullptr && g->completed;
 }
 
 /* static */ bool ScriptGoal::DoQuestion(uint16 uniqueid, uint8 target, bool is_client, Text *question, QuestionType type, int buttons)
@@ -114,7 +114,7 @@
 	CCountedPtr<Text> counter(question);
 
 	EnforcePrecondition(false, ScriptObject::GetCompany() == OWNER_DEITY);
-	EnforcePrecondition(false, question != NULL);
+	EnforcePrecondition(false, question != nullptr);
 	const char *text = question->GetEncodedText();
 	EnforcePreconditionEncodedText(false, text);
 	EnforcePrecondition(false, CountBits(buttons) >= 1 && CountBits(buttons) <= 3);
diff --git a/src/script/api/script_goal.hpp b/src/script/api/script_goal.hpp
index f5dfba095..b8c0873a2 100644
--- a/src/script/api/script_goal.hpp
+++ b/src/script/api/script_goal.hpp
@@ -99,7 +99,7 @@ public:
 	 * @param destination The destination of the \a type type.
 	 * @return The new GoalID, or GOAL_INVALID if it failed.
 	 * @pre No ScriptCompanyMode may be in scope.
-	 * @pre goal != NULL && len(goal) != 0.
+	 * @pre goal != nullptr && len(goal) != 0.
 	 * @pre company == COMPANY_INVALID || ResolveCompanyID(company) != COMPANY_INVALID.
 	 * @pre if type is GT_STORY_PAGE, the company of the goal and the company of the story page need to match:
 	 *       \li Global goals can only reference global story pages.
@@ -122,7 +122,7 @@ public:
 	 * @param goal The new goal text (can be either a raw string, or a ScriptText object).
 	 * @return True if the action succeeded.
 	 * @pre No ScriptCompanyMode may be in scope.
-	 * @pre goal != NULL && len(goal) != 0.
+	 * @pre goal != nullptr && len(goal) != 0.
 	 * @pre IsValidGoal(goal_id).
 	 */
 	static bool SetText(GoalID goal_id, Text *goal);
@@ -133,7 +133,7 @@ public:
 	 * the progress string short.
 	 * @param goal_id The goal to update.
 	 * @param progress The new progress text for the goal (can be either a raw string,
-	 * or a ScriptText object). To clear the progress string you can pass NULL or an
+	 * or a ScriptText object). To clear the progress string you can pass nullptr or an
 	 * empty string.
 	 * @return True if the action succeeded.
 	 * @pre No ScriptCompanyMode may be in scope.
@@ -169,7 +169,7 @@ public:
 	 * @param buttons Any combinations (at least 1, up to 3) of buttons defined in QuestionButton. Like BUTTON_YES + BUTTON_NO.
 	 * @return True if the action succeeded.
 	 * @pre No ScriptCompanyMode may be in scope.
-	 * @pre question != NULL && len(question) != 0.
+	 * @pre question != nullptr && len(question) != 0.
 	 * @pre company == COMPANY_INVALID || ResolveCompanyID(company) != COMPANY_INVALID.
 	 * @pre CountBits(buttons) >= 1 && CountBits(buttons) <= 3.
 	 * @note Replies to the question are given by you via the event ScriptEvent_GoalQuestionAnswer.
@@ -187,7 +187,7 @@ public:
 	 * @return True if the action succeeded.
 	 * @pre No ScriptCompanyMode may be in scope.
 	 * @pre ScriptGame::IsMultiplayer()
-	 * @pre question != NULL && len(question) != 0.
+	 * @pre question != nullptr && len(question) != 0.
 	 * @pre ResolveClientID(client) != CLIENT_INVALID.
 	 * @pre CountBits(buttons) >= 1 && CountBits(buttons) <= 3.
 	 * @note Replies to the question are given by you via the event ScriptEvent_GoalQuestionAnswer.
diff --git a/src/script/api/script_group.cpp b/src/script/api/script_group.cpp
index fcae6c3d2..55f5ffdeb 100644
--- a/src/script/api/script_group.cpp
+++ b/src/script/api/script_group.cpp
@@ -25,12 +25,12 @@
 /* static */ bool ScriptGroup::IsValidGroup(GroupID group_id)
 {
 	const Group *g = ::Group::GetIfValid(group_id);
-	return g != NULL && g->owner == ScriptObject::GetCompany();
+	return g != nullptr && g->owner == ScriptObject::GetCompany();
 }
 
 /* static */ ScriptGroup::GroupID ScriptGroup::CreateGroup(ScriptVehicle::VehicleType vehicle_type, GroupID parent_group_id)
 {
-	if (!ScriptObject::DoCommand(0, (::VehicleType)vehicle_type, parent_group_id, CMD_CREATE_GROUP, NULL, &ScriptInstance::DoCommandReturnGroupID)) return GROUP_INVALID;
+	if (!ScriptObject::DoCommand(0, (::VehicleType)vehicle_type, parent_group_id, CMD_CREATE_GROUP, nullptr, &ScriptInstance::DoCommandReturnGroupID)) return GROUP_INVALID;
 
 	/* In case of test-mode, we return GroupID 0 */
 	return (ScriptGroup::GroupID)0;
@@ -55,7 +55,7 @@
 	CCountedPtr<Text> counter(name);
 
 	EnforcePrecondition(false, IsValidGroup(group_id));
-	EnforcePrecondition(false, name != NULL);
+	EnforcePrecondition(false, name != nullptr);
 	const char *text = name->GetDecodedText();
 	EnforcePreconditionEncodedText(false, text);
 	EnforcePreconditionCustomError(false, ::Utf8StringLength(text) < MAX_LENGTH_GROUP_NAME_CHARS, ScriptError::ERR_PRECONDITION_STRING_TOO_LONG);
@@ -65,7 +65,7 @@
 
 /* static */ char *ScriptGroup::GetName(GroupID group_id)
 {
-	if (!IsValidGroup(group_id)) return NULL;
+	if (!IsValidGroup(group_id)) return nullptr;
 
 	::SetDParam(0, group_id);
 	return GetString(STR_GROUP_NAME);
diff --git a/src/script/api/script_group.hpp b/src/script/api/script_group.hpp
index 6e7deb0b7..f44163bba 100644
--- a/src/script/api/script_group.hpp
+++ b/src/script/api/script_group.hpp
@@ -71,7 +71,7 @@ public:
 	 * @param group_id The group to set the name for.
 	 * @param name The name for the group (can be either a raw string, or a ScriptText object).
 	 * @pre IsValidGroup(group_id).
-	 * @pre name != NULL && len(name) != 0
+	 * @pre name != nullptr && len(name) != 0
 	 * @exception ScriptError::ERR_NAME_IS_NOT_UNIQUE
 	 * @return True if and only if the name was changed.
 	 */
diff --git a/src/script/api/script_industry.cpp b/src/script/api/script_industry.cpp
index 68bb9003d..e72f9955b 100644
--- a/src/script/api/script_industry.cpp
+++ b/src/script/api/script_industry.cpp
@@ -39,7 +39,7 @@
 
 /* static */ char *ScriptIndustry::GetName(IndustryID industry_id)
 {
-	if (!IsValidIndustry(industry_id)) return NULL;
+	if (!IsValidIndustry(industry_id)) return nullptr;
 
 	::SetDParam(0, industry_id);
 	return GetString(STR_INDUSTRY_NAME);
diff --git a/src/script/api/script_industrytype.cpp b/src/script/api/script_industrytype.cpp
index 1ac59975d..e154705bb 100644
--- a/src/script/api/script_industrytype.cpp
+++ b/src/script/api/script_industrytype.cpp
@@ -59,14 +59,14 @@
 
 /* static */ char *ScriptIndustryType::GetName(IndustryType industry_type)
 {
-	if (!IsValidIndustryType(industry_type)) return NULL;
+	if (!IsValidIndustryType(industry_type)) return nullptr;
 
 	return GetString(::GetIndustrySpec(industry_type)->name);
 }
 
 /* static */ ScriptList *ScriptIndustryType::GetProducedCargo(IndustryType industry_type)
 {
-	if (!IsValidIndustryType(industry_type)) return NULL;
+	if (!IsValidIndustryType(industry_type)) return nullptr;
 
 	const IndustrySpec *ins = ::GetIndustrySpec(industry_type);
 
@@ -80,7 +80,7 @@
 
 /* static */ ScriptList *ScriptIndustryType::GetAcceptedCargo(IndustryType industry_type)
 {
-	if (!IsValidIndustryType(industry_type)) return NULL;
+	if (!IsValidIndustryType(industry_type)) return nullptr;
 
 	const IndustrySpec *ins = ::GetIndustrySpec(industry_type);
 
diff --git a/src/script/api/script_list.cpp b/src/script/api/script_list.cpp
index d0c72b5bb..13545c422 100644
--- a/src/script/api/script_list.cpp
+++ b/src/script/api/script_list.cpp
@@ -109,7 +109,7 @@ public:
 
 	void End()
 	{
-		this->bucket_list = NULL;
+		this->bucket_list = nullptr;
 		this->has_no_more_items = true;
 		this->item_next = 0;
 	}
@@ -119,7 +119,7 @@ public:
 	 */
 	void FindNext()
 	{
-		if (this->bucket_list == NULL) {
+		if (this->bucket_list == nullptr) {
 			this->has_no_more_items = true;
 			return;
 		}
@@ -128,7 +128,7 @@ public:
 		if (this->bucket_list_iter == this->bucket_list->end()) {
 			this->bucket_iter++;
 			if (this->bucket_iter == this->list->buckets.end()) {
-				this->bucket_list = NULL;
+				this->bucket_list = nullptr;
 				return;
 			}
 			this->bucket_list = &(*this->bucket_iter).second;
@@ -203,7 +203,7 @@ public:
 
 	void End()
 	{
-		this->bucket_list = NULL;
+		this->bucket_list = nullptr;
 		this->has_no_more_items = true;
 		this->item_next = 0;
 	}
@@ -213,14 +213,14 @@ public:
 	 */
 	void FindNext()
 	{
-		if (this->bucket_list == NULL) {
+		if (this->bucket_list == nullptr) {
 			this->has_no_more_items = true;
 			return;
 		}
 
 		if (this->bucket_list_iter == this->bucket_list->begin()) {
 			if (this->bucket_iter == this->list->buckets.begin()) {
-				this->bucket_list = NULL;
+				this->bucket_list = nullptr;
 				return;
 			}
 			this->bucket_iter--;
diff --git a/src/script/api/script_list.hpp b/src/script/api/script_list.hpp
index 1fbafe3d9..b32ebc463 100644
--- a/src/script/api/script_list.hpp
+++ b/src/script/api/script_list.hpp
@@ -198,7 +198,7 @@ public:
 	/**
 	 * Remove everything that is in the given list from this list (same item index that is).
 	 * @param list the list of items to remove.
-	 * @pre list != NULL
+	 * @pre list != nullptr
 	 */
 	void RemoveList(ScriptList *list);
 
@@ -242,7 +242,7 @@ public:
 	/**
 	 * Keeps everything that is in the given list from this list (same item index that is).
 	 * @param list the list of items to keep.
-	 * @pre list != NULL
+	 * @pre list != nullptr
 	 */
 	void KeepList(ScriptList *list);
 
diff --git a/src/script/api/script_log.cpp b/src/script/api/script_log.cpp
index d9fbbde98..b40ed97aa 100644
--- a/src/script/api/script_log.cpp
+++ b/src/script/api/script_log.cpp
@@ -35,7 +35,7 @@
 
 /* static */ void ScriptLog::Log(ScriptLog::ScriptLogType level, const char *message)
 {
-	if (ScriptObject::GetLogPointer() == NULL) {
+	if (ScriptObject::GetLogPointer() == nullptr) {
 		ScriptObject::GetLogPointer() = new LogData();
 		LogData *log = (LogData *)ScriptObject::GetLogPointer();
 
@@ -59,7 +59,7 @@
 
 	/* Cut string after first \n */
 	char *p;
-	while ((p = strchr(log->lines[log->pos], '\n')) != NULL) {
+	while ((p = strchr(log->lines[log->pos], '\n')) != nullptr) {
 		*p = '\0';
 		break;
 	}
diff --git a/src/script/api/script_marine.cpp b/src/script/api/script_marine.cpp
index 434ec11ac..bba361cec 100644
--- a/src/script/api/script_marine.cpp
+++ b/src/script/api/script_marine.cpp
@@ -166,9 +166,9 @@
 /* static */ Money ScriptMarine::GetBuildCost(BuildType build_type)
 {
 	switch (build_type) {
-		case BT_DOCK:  return ::GetPrice(PR_BUILD_STATION_DOCK, 1, NULL);
-		case BT_DEPOT: return ::GetPrice(PR_BUILD_DEPOT_SHIP, 1, NULL);
-		case BT_BUOY:  return ::GetPrice(PR_BUILD_WAYPOINT_BUOY, 1, NULL);
+		case BT_DOCK:  return ::GetPrice(PR_BUILD_STATION_DOCK, 1, nullptr);
+		case BT_DEPOT: return ::GetPrice(PR_BUILD_DEPOT_SHIP, 1, nullptr);
+		case BT_BUOY:  return ::GetPrice(PR_BUILD_WAYPOINT_BUOY, 1, nullptr);
 		default: return -1;
 	}
 }
diff --git a/src/script/api/script_news.cpp b/src/script/api/script_news.cpp
index 5f84f96d6..0c2ca3792 100644
--- a/src/script/api/script_news.cpp
+++ b/src/script/api/script_news.cpp
@@ -25,7 +25,7 @@
 {
 	CCountedPtr<Text> counter(text);
 
-	EnforcePrecondition(false, text != NULL);
+	EnforcePrecondition(false, text != nullptr);
 	const char *encoded = text->GetEncodedText();
 	EnforcePreconditionEncodedText(false, encoded);
 	EnforcePrecondition(false, type == NT_ECONOMY || type == NT_SUBSIDIES || type == NT_GENERAL);
diff --git a/src/script/api/script_news.hpp b/src/script/api/script_news.hpp
index ca0656608..441419338 100644
--- a/src/script/api/script_news.hpp
+++ b/src/script/api/script_news.hpp
@@ -61,7 +61,7 @@ public:
 	 *  - For #NR_TOWN this parameter should be a valid townID (ScriptTown::IsValidTown).
 	 * @return True if the action succeeded.
 	 * @pre type must be #NT_ECONOMY, #NT_SUBSIDIES, or #NT_GENERAL.
-	 * @pre text != NULL.
+	 * @pre text != nullptr.
 	 * @pre company == COMPANY_INVALID || ResolveCompanyID(company) != COMPANY_INVALID.
 	 * @pre The \a reference condition must be fulfilled.
 	 */
diff --git a/src/script/api/script_object.cpp b/src/script/api/script_object.cpp
index 7a22e3ab7..67ab7e40d 100644
--- a/src/script/api/script_object.cpp
+++ b/src/script/api/script_object.cpp
@@ -36,7 +36,7 @@ static ScriptStorage *GetStorage()
 }
 
 
-/* static */ ScriptInstance *ScriptObject::ActiveInstance::active = NULL;
+/* static */ ScriptInstance *ScriptObject::ActiveInstance::active = nullptr;
 
 ScriptObject::ActiveInstance::ActiveInstance(ScriptInstance *instance)
 {
@@ -51,7 +51,7 @@ ScriptObject::ActiveInstance::~ActiveInstance()
 
 /* static */ ScriptInstance *ScriptObject::GetActiveInstance()
 {
-	assert(ScriptObject::ActiveInstance::active != NULL);
+	assert(ScriptObject::ActiveInstance::active != nullptr);
 	return ScriptObject::ActiveInstance::active;
 }
 
@@ -296,16 +296,16 @@ ScriptObject::ActiveInstance::~ActiveInstance()
 	}
 
 	/* Set the default callback to return a true/false result of the DoCommand */
-	if (callback == NULL) callback = &ScriptInstance::DoCommandReturn;
+	if (callback == nullptr) callback = &ScriptInstance::DoCommandReturn;
 
 	/* Are we only interested in the estimate costs? */
-	bool estimate_only = GetDoCommandMode() != NULL && !GetDoCommandMode()();
+	bool estimate_only = GetDoCommandMode() != nullptr && !GetDoCommandMode()();
 
 	/* Only set p2 when the command does not come from the network. */
 	if (GetCommandFlags(cmd) & CMD_CLIENT_ID && p2 == 0) p2 = UINT32_MAX;
 
 	/* Try to perform the command. */
-	CommandCost res = ::DoCommandPInternal(tile, p1, p2, cmd, (_networking && !_generating_world) ? ScriptObject::GetActiveInstance()->GetDoCommandCallback() : NULL, text, false, estimate_only);
+	CommandCost res = ::DoCommandPInternal(tile, p1, p2, cmd, (_networking && !_generating_world) ? ScriptObject::GetActiveInstance()->GetDoCommandCallback() : nullptr, text, false, estimate_only);
 
 	/* We failed; set the error and bail out */
 	if (res.Failed()) {
@@ -328,7 +328,7 @@ ScriptObject::ActiveInstance::~ActiveInstance()
 
 	if (_generating_world) {
 		IncreaseDoCommandCosts(res.GetCost());
-		if (callback != NULL) {
+		if (callback != nullptr) {
 			/* Insert return value into to stack and throw a control code that
 			 * the return value in the stack should be used. */
 			callback(GetActiveInstance());
diff --git a/src/script/api/script_object.hpp b/src/script/api/script_object.hpp
index 482e76f66..6725f0ed1 100644
--- a/src/script/api/script_object.hpp
+++ b/src/script/api/script_object.hpp
@@ -69,7 +69,7 @@ protected:
 	/**
 	 * Executes a raw DoCommand for the script.
 	 */
-	static bool DoCommand(TileIndex tile, uint32 p1, uint32 p2, uint cmd, const char *text = NULL, Script_SuspendCallbackProc *callback = NULL);
+	static bool DoCommand(TileIndex tile, uint32 p1, uint32 p2, uint cmd, const char *text = nullptr, Script_SuspendCallbackProc *callback = nullptr);
 
 	/**
 	 * Sets the DoCommand costs counter to a value.
diff --git a/src/script/api/script_order.cpp b/src/script/api/script_order.cpp
index a1390bf8f..04f7c69f4 100644
--- a/src/script/api/script_order.cpp
+++ b/src/script/api/script_order.cpp
@@ -66,7 +66,7 @@ static const Order *ResolveOrder(VehicleID vehicle_id, ScriptOrder::OrderPositio
 		const Order *order = &v->current_order;
 		if (order->GetType() == OT_GOTO_DEPOT && !(order->GetDepotOrderType() & ODTFB_PART_OF_ORDERS)) return order;
 		order_position = ScriptOrder::ResolveOrderPosition(vehicle_id, order_position);
-		if (order_position == ScriptOrder::ORDER_INVALID) return NULL;
+		if (order_position == ScriptOrder::ORDER_INVALID) return nullptr;
 	}
 	const Order *order = v->GetFirstOrder();
 	while (order->GetType() == OT_IMPLICIT) order = order->next;
@@ -108,7 +108,7 @@ static int ScriptOrderPositionToRealOrderPosition(VehicleID vehicle_id, ScriptOr
 	if (!IsValidVehicleOrder(vehicle_id, order_position)) return false;
 
 	const Order *order = ::ResolveOrder(vehicle_id, order_position);
-	return order != NULL && order->GetType() == OT_GOTO_STATION;
+	return order != nullptr && order->GetType() == OT_GOTO_STATION;
 }
 
 /* static */ bool ScriptOrder::IsGotoDepotOrder(VehicleID vehicle_id, OrderPosition order_position)
@@ -116,7 +116,7 @@ static int ScriptOrderPositionToRealOrderPosition(VehicleID vehicle_id, ScriptOr
 	if (!IsValidVehicleOrder(vehicle_id, order_position)) return false;
 
 	const Order *order = ::ResolveOrder(vehicle_id, order_position);
-	return order != NULL && order->GetType() == OT_GOTO_DEPOT;
+	return order != nullptr && order->GetType() == OT_GOTO_DEPOT;
 }
 
 /* static */ bool ScriptOrder::IsGotoWaypointOrder(VehicleID vehicle_id, OrderPosition order_position)
@@ -124,7 +124,7 @@ static int ScriptOrderPositionToRealOrderPosition(VehicleID vehicle_id, ScriptOr
 	if (!IsValidVehicleOrder(vehicle_id, order_position)) return false;
 
 	const Order *order = ::ResolveOrder(vehicle_id, order_position);
-	return order != NULL && order->GetType() == OT_GOTO_WAYPOINT;
+	return order != nullptr && order->GetType() == OT_GOTO_WAYPOINT;
 }
 
 /* static */ bool ScriptOrder::IsConditionalOrder(VehicleID vehicle_id, OrderPosition order_position)
@@ -150,7 +150,7 @@ static int ScriptOrderPositionToRealOrderPosition(VehicleID vehicle_id, ScriptOr
 	if (!IsValidVehicleOrder(vehicle_id, order_position)) return false;
 
 	const Order *order = ::ResolveOrder(vehicle_id, order_position);
-	return order != NULL && order->IsRefit();
+	return order != nullptr && order->IsRefit();
 }
 
 /* static */ bool ScriptOrder::IsCurrentOrderPartOfOrderList(VehicleID vehicle_id)
@@ -240,7 +240,7 @@ static int ScriptOrderPositionToRealOrderPosition(VehicleID vehicle_id, ScriptOr
 	if (!IsValidVehicleOrder(vehicle_id, order_position)) return INVALID_TILE;
 
 	const Order *order = ::ResolveOrder(vehicle_id, order_position);
-	if (order == NULL || order->GetType() == OT_CONDITIONAL) return INVALID_TILE;
+	if (order == nullptr || order->GetType() == OT_CONDITIONAL) return INVALID_TILE;
 	const Vehicle *v = ::Vehicle::Get(vehicle_id);
 
 	switch (order->GetType()) {
@@ -263,9 +263,9 @@ static int ScriptOrderPositionToRealOrderPosition(VehicleID vehicle_id, ScriptOr
 				}
 			} else if (st->dock_tile != INVALID_TILE) {
 				return st->dock_tile;
-			} else if (st->bus_stops != NULL) {
+			} else if (st->bus_stops != nullptr) {
 				return st->bus_stops->xy;
-			} else if (st->truck_stops != NULL) {
+			} else if (st->truck_stops != nullptr) {
 				return st->truck_stops->xy;
 			} else if (st->airport.tile != INVALID_TILE) {
 				TILE_AREA_LOOP(tile, st->airport) {
@@ -294,7 +294,7 @@ static int ScriptOrderPositionToRealOrderPosition(VehicleID vehicle_id, ScriptOr
 	if (!IsValidVehicleOrder(vehicle_id, order_position)) return OF_INVALID;
 
 	const Order *order = ::ResolveOrder(vehicle_id, order_position);
-	if (order == NULL || order->GetType() == OT_CONDITIONAL || order->GetType() == OT_DUMMY) return OF_INVALID;
+	if (order == nullptr || order->GetType() == OT_CONDITIONAL || order->GetType() == OT_DUMMY) return OF_INVALID;
 
 	ScriptOrderFlags order_flags = OF_NONE;
 	order_flags |= (ScriptOrderFlags)order->GetNonStopType();
@@ -586,7 +586,7 @@ static void _DoCommandReturnSetOrderFlags(class ScriptInstance *instance)
 	EnforcePrecondition(false, (order_flags & OF_GOTO_NEAREST_DEPOT) == (current & OF_GOTO_NEAREST_DEPOT));
 
 	if ((current & OF_NON_STOP_FLAGS) != (order_flags & OF_NON_STOP_FLAGS)) {
-		return ScriptObject::DoCommand(0, vehicle_id | (order_pos << 20), (order_flags & OF_NON_STOP_FLAGS) << 4 | MOF_NON_STOP, CMD_MODIFY_ORDER, NULL, &::_DoCommandReturnSetOrderFlags);
+		return ScriptObject::DoCommand(0, vehicle_id | (order_pos << 20), (order_flags & OF_NON_STOP_FLAGS) << 4 | MOF_NON_STOP, CMD_MODIFY_ORDER, nullptr, &::_DoCommandReturnSetOrderFlags);
 	}
 
 	switch (order->GetType()) {
@@ -595,16 +595,16 @@ static void _DoCommandReturnSetOrderFlags(class ScriptInstance *instance)
 				uint data = DA_ALWAYS_GO;
 				if (order_flags & OF_SERVICE_IF_NEEDED) data = DA_SERVICE;
 				if (order_flags & OF_STOP_IN_DEPOT) data = DA_STOP;
-				return ScriptObject::DoCommand(0, vehicle_id | (order_pos << 20), (data << 4) | MOF_DEPOT_ACTION, CMD_MODIFY_ORDER, NULL, &::_DoCommandReturnSetOrderFlags);
+				return ScriptObject::DoCommand(0, vehicle_id | (order_pos << 20), (data << 4) | MOF_DEPOT_ACTION, CMD_MODIFY_ORDER, nullptr, &::_DoCommandReturnSetOrderFlags);
 			}
 			break;
 
 		case OT_GOTO_STATION:
 			if ((current & OF_UNLOAD_FLAGS) != (order_flags & OF_UNLOAD_FLAGS)) {
-				return ScriptObject::DoCommand(0, vehicle_id | (order_pos << 20), (order_flags & OF_UNLOAD_FLAGS) << 2 | MOF_UNLOAD, CMD_MODIFY_ORDER, NULL, &::_DoCommandReturnSetOrderFlags);
+				return ScriptObject::DoCommand(0, vehicle_id | (order_pos << 20), (order_flags & OF_UNLOAD_FLAGS) << 2 | MOF_UNLOAD, CMD_MODIFY_ORDER, nullptr, &::_DoCommandReturnSetOrderFlags);
 			}
 			if ((current & OF_LOAD_FLAGS) != (order_flags & OF_LOAD_FLAGS)) {
-				return ScriptObject::DoCommand(0, vehicle_id | (order_pos << 20), (order_flags & OF_LOAD_FLAGS) >> 1 | MOF_LOAD, CMD_MODIFY_ORDER, NULL, &::_DoCommandReturnSetOrderFlags);
+				return ScriptObject::DoCommand(0, vehicle_id | (order_pos << 20), (order_flags & OF_LOAD_FLAGS) >> 1 | MOF_LOAD, CMD_MODIFY_ORDER, nullptr, &::_DoCommandReturnSetOrderFlags);
 			}
 			break;
 
diff --git a/src/script/api/script_rail.cpp b/src/script/api/script_rail.cpp
index f7682cfd8..d4580fc32 100644
--- a/src/script/api/script_rail.cpp
+++ b/src/script/api/script_rail.cpp
@@ -25,7 +25,7 @@
 
 /* static */ char *ScriptRail::GetName(RailType rail_type)
 {
-	if (!IsRailTypeAvailable(rail_type)) return NULL;
+	if (!IsRailTypeAvailable(rail_type)) return nullptr;
 
 	return GetString(GetRailTypeInfo((::RailType)rail_type)->strings.menu_text);
 }
@@ -185,7 +185,7 @@
 	if (res != CALLBACK_FAILED) {
 		int index = 0;
 		const StationSpec *spec = StationClass::GetByGrf(file->grfid, res, &index);
-		if (spec == NULL) {
+		if (spec == nullptr) {
 			DEBUG(grf, 1, "%s returned an invalid station ID for 'AI construction/purchase selection (18)' callback", file->filename);
 		} else {
 			/* We might have gotten an usable station spec. Try to build it, but if it fails we'll fall back to the original station. */
@@ -487,10 +487,10 @@ static bool IsValidSignalType(int signal_type)
 
 	switch (build_type) {
 		case BT_TRACK:    return ::RailBuildCost((::RailType)railtype);
-		case BT_SIGNAL:   return ::GetPrice(PR_BUILD_SIGNALS, 1, NULL);
-		case BT_DEPOT:    return ::GetPrice(PR_BUILD_DEPOT_TRAIN, 1, NULL);
-		case BT_STATION:  return ::GetPrice(PR_BUILD_STATION_RAIL, 1, NULL) + ::GetPrice(PR_BUILD_STATION_RAIL_LENGTH, 1, NULL);
-		case BT_WAYPOINT: return ::GetPrice(PR_BUILD_WAYPOINT_RAIL, 1, NULL);
+		case BT_SIGNAL:   return ::GetPrice(PR_BUILD_SIGNALS, 1, nullptr);
+		case BT_DEPOT:    return ::GetPrice(PR_BUILD_DEPOT_TRAIN, 1, nullptr);
+		case BT_STATION:  return ::GetPrice(PR_BUILD_STATION_RAIL, 1, nullptr) + ::GetPrice(PR_BUILD_STATION_RAIL_LENGTH, 1, nullptr);
+		case BT_WAYPOINT: return ::GetPrice(PR_BUILD_WAYPOINT_RAIL, 1, nullptr);
 		default: return -1;
 	}
 }
diff --git a/src/script/api/script_road.cpp b/src/script/api/script_road.cpp
index 44972cdea..74899f8bb 100644
--- a/src/script/api/script_road.cpp
+++ b/src/script/api/script_road.cpp
@@ -588,10 +588,10 @@ static bool NeighbourHasReachableRoad(::RoadTypes rts, TileIndex start_tile, Dia
 	if (!ScriptRoad::IsRoadTypeAvailable(roadtype)) return -1;
 
 	switch (build_type) {
-		case BT_ROAD:       return ::GetPrice(PR_BUILD_ROAD, 1, NULL);
-		case BT_DEPOT:      return ::GetPrice(PR_BUILD_DEPOT_ROAD, 1, NULL);
-		case BT_BUS_STOP:   return ::GetPrice(PR_BUILD_STATION_BUS, 1, NULL);
-		case BT_TRUCK_STOP: return ::GetPrice(PR_BUILD_STATION_TRUCK, 1, NULL);
+		case BT_ROAD:       return ::GetPrice(PR_BUILD_ROAD, 1, nullptr);
+		case BT_DEPOT:      return ::GetPrice(PR_BUILD_DEPOT_ROAD, 1, nullptr);
+		case BT_BUS_STOP:   return ::GetPrice(PR_BUILD_STATION_BUS, 1, nullptr);
+		case BT_TRUCK_STOP: return ::GetPrice(PR_BUILD_STATION_TRUCK, 1, nullptr);
 		default: return -1;
 	}
 }
diff --git a/src/script/api/script_sign.cpp b/src/script/api/script_sign.cpp
index 236e1df7e..33c8e9a28 100644
--- a/src/script/api/script_sign.cpp
+++ b/src/script/api/script_sign.cpp
@@ -23,7 +23,7 @@
 /* static */ bool ScriptSign::IsValidSign(SignID sign_id)
 {
 	const Sign *si = ::Sign::GetIfValid(sign_id);
-	return si != NULL && (si->owner == ScriptObject::GetCompany() || si->owner == OWNER_DEITY);
+	return si != nullptr && (si->owner == ScriptObject::GetCompany() || si->owner == OWNER_DEITY);
 }
 
 /* static */ ScriptCompany::CompanyID ScriptSign::GetOwner(SignID sign_id)
@@ -38,7 +38,7 @@
 	CCountedPtr<Text> counter(name);
 
 	EnforcePrecondition(false, IsValidSign(sign_id));
-	EnforcePrecondition(false, name != NULL);
+	EnforcePrecondition(false, name != nullptr);
 	const char *text = name->GetDecodedText();
 	EnforcePreconditionEncodedText(false, text);
 	EnforcePreconditionCustomError(false, ::Utf8StringLength(text) < MAX_LENGTH_SIGN_NAME_CHARS, ScriptError::ERR_PRECONDITION_STRING_TOO_LONG);
@@ -48,7 +48,7 @@
 
 /* static */ char *ScriptSign::GetName(SignID sign_id)
 {
-	if (!IsValidSign(sign_id)) return NULL;
+	if (!IsValidSign(sign_id)) return nullptr;
 
 	::SetDParam(0, sign_id);
 	return GetString(STR_SIGN_NAME);
@@ -73,7 +73,7 @@
 	CCountedPtr<Text> counter(name);
 
 	EnforcePrecondition(INVALID_SIGN, ::IsValidTile(location));
-	EnforcePrecondition(INVALID_SIGN, name != NULL);
+	EnforcePrecondition(INVALID_SIGN, name != nullptr);
 	const char *text = name->GetDecodedText();
 	EnforcePreconditionEncodedText(INVALID_SIGN, text);
 	EnforcePreconditionCustomError(INVALID_SIGN, ::Utf8StringLength(text) < MAX_LENGTH_SIGN_NAME_CHARS, ScriptError::ERR_PRECONDITION_STRING_TOO_LONG);
diff --git a/src/script/api/script_sign.hpp b/src/script/api/script_sign.hpp
index e5c2164da..4b0483e98 100644
--- a/src/script/api/script_sign.hpp
+++ b/src/script/api/script_sign.hpp
@@ -45,7 +45,7 @@ public:
 	 * @param sign_id The sign to set the name for.
 	 * @param name The name for the sign (can be either a raw string, or a ScriptText object).
 	 * @pre IsValidSign(sign_id).
-	 * @pre name != NULL && len(name) != 0.
+	 * @pre name != nullptr && len(name) != 0.
 	 * @exception ScriptError::ERR_NAME_IS_NOT_UNIQUE
 	 * @return True if and only if the name was changed.
 	 */
@@ -81,7 +81,7 @@ public:
 	 * @param location The place to build the sign.
 	 * @param name The text to place on the sign (can be either a raw string, or a ScriptText object).
 	 * @pre ScriptMap::IsValidTile(location).
-	 * @pre name != NULL && len(name) != 0.
+	 * @pre name != nullptr && len(name) != 0.
 	 * @exception ScriptSign::ERR_SIGN_TOO_MANY_SIGNS
 	 * @return The SignID of the build sign (use IsValidSign() to check for validity).
 	 *   In test-mode it returns 0 if successful, or any other value to indicate
diff --git a/src/script/api/script_station.cpp b/src/script/api/script_station.cpp
index 5ed43e0a6..3b3bae33c 100644
--- a/src/script/api/script_station.cpp
+++ b/src/script/api/script_station.cpp
@@ -23,7 +23,7 @@
 /* static */ bool ScriptStation::IsValidStation(StationID station_id)
 {
 	const Station *st = ::Station::GetIfValid(station_id);
-	return st != NULL && (st->owner == ScriptObject::GetCompany() || ScriptObject::GetCompany() == OWNER_DEITY || st->owner == OWNER_NONE);
+	return st != nullptr && (st->owner == ScriptObject::GetCompany() || ScriptObject::GetCompany() == OWNER_DEITY || st->owner == OWNER_NONE);
 }
 
 /* static */ ScriptCompany::CompanyID ScriptStation::GetOwner(StationID station_id)
@@ -213,10 +213,10 @@ template<bool Tfrom, bool Tvia>
 
 	::RoadTypes r = RoadTypeToRoadTypes((::RoadType)road_type);
 
-	for (const RoadStop *rs = ::Station::Get(station_id)->GetPrimaryRoadStop(ROADSTOP_BUS); rs != NULL; rs = rs->next) {
+	for (const RoadStop *rs = ::Station::Get(station_id)->GetPrimaryRoadStop(ROADSTOP_BUS); rs != nullptr; rs = rs->next) {
 		if ((::GetRoadTypes(rs->xy) & r) != 0) return true;
 	}
-	for (const RoadStop *rs = ::Station::Get(station_id)->GetPrimaryRoadStop(ROADSTOP_TRUCK); rs != NULL; rs = rs->next) {
+	for (const RoadStop *rs = ::Station::Get(station_id)->GetPrimaryRoadStop(ROADSTOP_TRUCK); rs != nullptr; rs = rs->next) {
 		if ((::GetRoadTypes(rs->xy) & r) != 0) return true;
 	}
 
diff --git a/src/script/api/script_stationlist.cpp b/src/script/api/script_stationlist.cpp
index 51a06b5a7..4bbb5fa67 100644
--- a/src/script/api/script_stationlist.cpp
+++ b/src/script/api/script_stationlist.cpp
@@ -32,7 +32,7 @@ ScriptStationList_Vehicle::ScriptStationList_Vehicle(VehicleID vehicle_id)
 
 	Vehicle *v = ::Vehicle::Get(vehicle_id);
 
-	for (Order *o = v->GetFirstOrder(); o != NULL; o = o->next) {
+	for (Order *o = v->GetFirstOrder(); o != nullptr; o = o->next) {
 		if (o->IsType(OT_GOTO_STATION)) this->AddItem(o->GetDestination());
 	}
 }
@@ -120,7 +120,7 @@ private:
 
 CargoCollector::CargoCollector(ScriptStationList_Cargo *parent,
 		StationID station_id, CargoID cargo, StationID other) :
-	list(parent), ge(NULL), other_station(other), last_key(INVALID_STATION), amount(0)
+	list(parent), ge(nullptr), other_station(other), last_key(INVALID_STATION), amount(0)
 {
 	if (!ScriptStation::IsValidStation(station_id)) return;
 	if (!ScriptCargo::IsValidCargo(cargo)) return;
@@ -176,7 +176,7 @@ template<ScriptStationList_Cargo::CargoSelector Tselector>
 void ScriptStationList_CargoWaiting::Add(StationID station_id, CargoID cargo, StationID other_station)
 {
 	CargoCollector collector(this, station_id, cargo, other_station);
-	if (collector.GE() == NULL) return;
+	if (collector.GE() == nullptr) return;
 
 	StationCargoList::ConstIterator iter = collector.GE()->cargo.Packets()->begin();
 	StationCargoList::ConstIterator end = collector.GE()->cargo.Packets()->end();
@@ -190,7 +190,7 @@ template<ScriptStationList_Cargo::CargoSelector Tselector>
 void ScriptStationList_CargoPlanned::Add(StationID station_id, CargoID cargo, StationID other_station)
 {
 	CargoCollector collector(this, station_id, cargo, other_station);
-	if (collector.GE() == NULL) return;
+	if (collector.GE() == nullptr) return;
 
 	FlowStatMap::const_iterator iter = collector.GE()->flows.begin();
 	FlowStatMap::const_iterator end = collector.GE()->flows.end();
@@ -215,7 +215,7 @@ ScriptStationList_CargoWaitingViaByFrom::ScriptStationList_CargoWaitingViaByFrom
 		StationID station_id, CargoID cargo, StationID via)
 {
 	CargoCollector collector(this, station_id, cargo, via);
-	if (collector.GE() == NULL) return;
+	if (collector.GE() == nullptr) return;
 
 	std::pair<StationCargoList::ConstIterator, StationCargoList::ConstIterator> range =
 			collector.GE()->cargo.Packets()->equal_range(via);
@@ -261,7 +261,7 @@ ScriptStationList_CargoPlannedFromByVia::ScriptStationList_CargoPlannedFromByVia
 		StationID station_id, CargoID cargo, StationID from)
 {
 	CargoCollector collector(this, station_id, cargo, from);
-	if (collector.GE() == NULL) return;
+	if (collector.GE() == nullptr) return;
 
 	FlowStatMap::const_iterator iter = collector.GE()->flows.find(from);
 	if (iter == collector.GE()->flows.end()) return;
diff --git a/src/script/api/script_story_page.cpp b/src/script/api/script_story_page.cpp
index 11820ec3f..e31ad71c3 100644
--- a/src/script/api/script_story_page.cpp
+++ b/src/script/api/script_story_page.cpp
@@ -48,7 +48,7 @@
 		c,
 		0,
 		CMD_CREATE_STORY_PAGE,
-		title != NULL? title->GetEncodedText() : NULL,
+		title != nullptr? title->GetEncodedText() : nullptr,
 		&ScriptInstance::DoCommandReturnStoryPageID)) return STORY_PAGE_INVALID;
 
 	/* In case of test-mode, we return StoryPageID 0 */
@@ -61,7 +61,7 @@
 
 	EnforcePrecondition(STORY_PAGE_ELEMENT_INVALID, ScriptObject::GetCompany() == OWNER_DEITY);
 	EnforcePrecondition(STORY_PAGE_ELEMENT_INVALID, IsValidStoryPage(story_page_id));
-	EnforcePrecondition(STORY_PAGE_ELEMENT_INVALID, (type != SPET_TEXT && type != SPET_LOCATION) || (text != NULL && !StrEmpty(text->GetEncodedText())));
+	EnforcePrecondition(STORY_PAGE_ELEMENT_INVALID, (type != SPET_TEXT && type != SPET_LOCATION) || (text != nullptr && !StrEmpty(text->GetEncodedText())));
 	EnforcePrecondition(STORY_PAGE_ELEMENT_INVALID, type != SPET_LOCATION || ::IsValidTile(reference));
 	EnforcePrecondition(STORY_PAGE_ELEMENT_INVALID, type != SPET_GOAL || ScriptGoal::IsValidGoal((ScriptGoal::GoalID)reference));
 	EnforcePrecondition(STORY_PAGE_ELEMENT_INVALID, type != SPET_GOAL || !(StoryPage::Get(story_page_id)->company == INVALID_COMPANY && Goal::Get(reference)->company != INVALID_COMPANY));
@@ -70,7 +70,7 @@
 			story_page_id + (type << 16),
 			type == SPET_GOAL ? reference : 0,
 			CMD_CREATE_STORY_PAGE_ELEMENT,
-			type == SPET_TEXT || type == SPET_LOCATION ? text->GetEncodedText() : NULL,
+			type == SPET_TEXT || type == SPET_LOCATION ? text->GetEncodedText() : nullptr,
 			&ScriptInstance::DoCommandReturnStoryPageElementID)) return STORY_PAGE_ELEMENT_INVALID;
 
 	/* In case of test-mode, we return StoryPageElementID 0 */
@@ -88,7 +88,7 @@
 	StoryPage *p = StoryPage::Get(pe->page);
 	::StoryPageElementType type = pe->type;
 
-	EnforcePrecondition(false, (type != ::SPET_TEXT && type != ::SPET_LOCATION) || (text != NULL && !StrEmpty(text->GetEncodedText())));
+	EnforcePrecondition(false, (type != ::SPET_TEXT && type != ::SPET_LOCATION) || (text != nullptr && !StrEmpty(text->GetEncodedText())));
 	EnforcePrecondition(false, type != ::SPET_LOCATION || ::IsValidTile(reference));
 	EnforcePrecondition(false, type != ::SPET_GOAL || ScriptGoal::IsValidGoal((ScriptGoal::GoalID)reference));
 	EnforcePrecondition(false, type != ::SPET_GOAL || !(p->company == INVALID_COMPANY && Goal::Get(reference)->company != INVALID_COMPANY));
@@ -97,7 +97,7 @@
 			story_page_element_id,
 			type == ::SPET_GOAL ? reference : 0,
 			CMD_UPDATE_STORY_PAGE_ELEMENT,
-			type == ::SPET_TEXT || type == ::SPET_LOCATION ? text->GetEncodedText() : NULL);
+			type == ::SPET_TEXT || type == ::SPET_LOCATION ? text->GetEncodedText() : nullptr);
 }
 
 /* static */ uint32 ScriptStoryPage::GetPageSortValue(StoryPageID story_page_id)
@@ -121,7 +121,7 @@
 	EnforcePrecondition(false, IsValidStoryPage(story_page_id));
 	EnforcePrecondition(false, ScriptObject::GetCompany() == OWNER_DEITY);
 
-	return ScriptObject::DoCommand(0, story_page_id, 0, CMD_SET_STORY_PAGE_TITLE, title != NULL? title->GetEncodedText() : NULL);
+	return ScriptObject::DoCommand(0, story_page_id, 0, CMD_SET_STORY_PAGE_TITLE, title != nullptr? title->GetEncodedText() : nullptr);
 }
 
 /* static */ ScriptCompany::CompanyID ScriptStoryPage::GetCompany(StoryPageID story_page_id)
@@ -147,7 +147,7 @@
 	EnforcePrecondition(false, IsValidStoryPage(story_page_id));
 	EnforcePrecondition(false, ScriptObject::GetCompany() == OWNER_DEITY);
 
-	return ScriptObject::DoCommand(0, story_page_id, date, CMD_SET_STORY_PAGE_DATE, NULL);
+	return ScriptObject::DoCommand(0, story_page_id, date, CMD_SET_STORY_PAGE_DATE, nullptr);
 }
 
 
diff --git a/src/script/api/script_story_page.hpp b/src/script/api/script_story_page.hpp
index c22d4c198..772c16200 100644
--- a/src/script/api/script_story_page.hpp
+++ b/src/script/api/script_story_page.hpp
@@ -97,7 +97,7 @@ public:
 	 * @return The new StoryPageElementID, or STORY_PAGE_ELEMENT_INVALID if it failed.
 	 * @pre No ScriptCompanyMode may be in scope.
 	 * @pre IsValidStoryPage(story_page).
-	 * @pre (type != SPET_TEXT && type != SPET_LOCATION) || (text != NULL && len(text) != 0).
+	 * @pre (type != SPET_TEXT && type != SPET_LOCATION) || (text != nullptr && len(text) != 0).
 	 * @pre type != SPET_LOCATION || ScriptMap::IsValidTile(reference).
 	 * @pre type != SPET_GOAL || ScriptGoal::IsValidGoal(reference).
 	 * @pre if type is SPET_GOAL and story_page is a global page, then referenced goal must be global.
@@ -112,7 +112,7 @@ public:
 	 * @return True if the action succeeded.
 	 * @pre No ScriptCompanyMode may be in scope.
 	 * @pre IsValidStoryPage(story_page).
-	 * @pre (type != SPET_TEXT && type != SPET_LOCATION) || (text != NULL && len(text) != 0).
+	 * @pre (type != SPET_TEXT && type != SPET_LOCATION) || (text != nullptr && len(text) != 0).
 	 * @pre type != SPET_LOCATION || ScriptMap::IsValidTile(reference).
 	 * @pre type != SPET_GOAL || ScriptGoal::IsValidGoal(reference).
 	 * @pre if type is SPET_GOAL and story_page is a global page, then referenced goal must be global.
diff --git a/src/script/api/script_text.cpp b/src/script/api/script_text.cpp
index e692be0ae..bfc866ac4 100644
--- a/src/script/api/script_text.cpp
+++ b/src/script/api/script_text.cpp
@@ -63,7 +63,7 @@ ScriptText::~ScriptText()
 {
 	for (int i = 0; i < SCRIPT_TEXT_MAX_PARAMETERS; i++) {
 		free(this->params[i]);
-		if (this->paramt[i] != NULL) this->paramt[i]->Release();
+		if (this->paramt[i] != nullptr) this->paramt[i]->Release();
 	}
 }
 
@@ -72,11 +72,11 @@ SQInteger ScriptText::_SetParam(int parameter, HSQUIRRELVM vm)
 	if (parameter >= SCRIPT_TEXT_MAX_PARAMETERS) return SQ_ERROR;
 
 	free(this->params[parameter]);
-	if (this->paramt[parameter] != NULL) this->paramt[parameter]->Release();
+	if (this->paramt[parameter] != nullptr) this->paramt[parameter]->Release();
 
 	this->parami[parameter] = 0;
-	this->params[parameter] = NULL;
-	this->paramt[parameter] = NULL;
+	this->params[parameter] = nullptr;
+	this->paramt[parameter] = nullptr;
 
 	switch (sq_gettype(vm, -1)) {
 		case OT_STRING: {
@@ -97,7 +97,7 @@ SQInteger ScriptText::_SetParam(int parameter, HSQUIRRELVM vm)
 		}
 
 		case OT_INSTANCE: {
-			SQUserPointer real_instance = NULL;
+			SQUserPointer real_instance = nullptr;
 			HSQOBJECT instance;
 
 			sq_getstackobj(vm, -1, &instance);
@@ -112,7 +112,7 @@ SQInteger ScriptText::_SetParam(int parameter, HSQUIRRELVM vm)
 
 			/* Get the 'real' instance of this class */
 			sq_getinstanceup(vm, -1, &real_instance, 0);
-			if (real_instance == NULL) return SQ_ERROR;
+			if (real_instance == nullptr) return SQ_ERROR;
 
 			ScriptText *value = static_cast<ScriptText *>(real_instance);
 			value->AddRef();
@@ -183,7 +183,7 @@ const char *ScriptText::GetEncodedText()
 	static char buf[1024];
 	int param_count = 0;
 	this->_GetEncodedText(buf, lastof(buf), param_count);
-	return (param_count > SCRIPT_TEXT_MAX_PARAMETERS) ? NULL : buf;
+	return (param_count > SCRIPT_TEXT_MAX_PARAMETERS) ? nullptr : buf;
 }
 
 char *ScriptText::_GetEncodedText(char *p, char *lastofp, int &param_count)
@@ -191,12 +191,12 @@ char *ScriptText::_GetEncodedText(char *p, char *lastofp, int &param_count)
 	p += Utf8Encode(p, SCC_ENCODED);
 	p += seprintf(p, lastofp, "%X", this->string);
 	for (int i = 0; i < this->paramc; i++) {
-		if (this->params[i] != NULL) {
+		if (this->params[i] != nullptr) {
 			p += seprintf(p, lastofp, ":\"%s\"", this->params[i]);
 			param_count++;
 			continue;
 		}
-		if (this->paramt[i] != NULL) {
+		if (this->paramt[i] != nullptr) {
 			p += seprintf(p, lastofp, ":");
 			p = this->paramt[i]->_GetEncodedText(p, lastofp, param_count);
 			continue;
@@ -211,7 +211,7 @@ char *ScriptText::_GetEncodedText(char *p, char *lastofp, int &param_count)
 const char *Text::GetDecodedText()
 {
 	const char *encoded_text = this->GetEncodedText();
-	if (encoded_text == NULL) return NULL;
+	if (encoded_text == nullptr) return nullptr;
 
 	static char buf[1024];
 	::SetDParamStr(0, encoded_text);
diff --git a/src/script/api/script_text.hpp b/src/script/api/script_text.hpp
index 0b82ffb20..12892a7e7 100644
--- a/src/script/api/script_text.hpp
+++ b/src/script/api/script_text.hpp
@@ -23,14 +23,14 @@ class Text : public ScriptObject {
 public:
 	/**
 	 * Convert a ScriptText to a normal string.
-	 * @return A string (in a static buffer), or NULL.
+	 * @return A string (in a static buffer), or nullptr.
 	 * @api -all
 	 */
 	virtual const char *GetEncodedText() = 0;
 
 	/**
 	 * Convert a #ScriptText into a decoded normal string.
-	 * @return A string (in a static buffer), or NULL.
+	 * @return A string (in a static buffer), or nullptr.
 	 * @api -all
 	 */
 	const char *GetDecodedText();
diff --git a/src/script/api/script_tile.cpp b/src/script/api/script_tile.cpp
index db9220acd..136461762 100644
--- a/src/script/api/script_tile.cpp
+++ b/src/script/api/script_tile.cpp
@@ -292,7 +292,7 @@
 	if (!::IsValidTile(tile)) return INVALID_TOWN;
 
 	Town *town = ::ClosestTownFromTile(tile, _settings_game.economy.dist_local_authority);
-	if (town == NULL) return INVALID_TOWN;
+	if (town == nullptr) return INVALID_TOWN;
 
 	return town->index;
 }
@@ -302,7 +302,7 @@
 	if (!::IsValidTile(tile)) return INVALID_TOWN;
 
 	Town *town = ::ClosestTownFromTile(tile, UINT_MAX);
-	if (town == NULL) return INVALID_TOWN;
+	if (town == nullptr) return INVALID_TOWN;
 
 	return town->index;
 }
@@ -310,14 +310,14 @@
 /* static */ Money ScriptTile::GetBuildCost(BuildType build_type)
 {
 	switch (build_type) {
-		case BT_FOUNDATION:   return ::GetPrice(PR_BUILD_FOUNDATION, 1, NULL);
-		case BT_TERRAFORM:    return ::GetPrice(PR_TERRAFORM, 1, NULL);
-		case BT_BUILD_TREES:  return ::GetPrice(PR_BUILD_TREES, 1, NULL);
-		case BT_CLEAR_GRASS:  return ::GetPrice(PR_CLEAR_GRASS, 1, NULL);
-		case BT_CLEAR_ROUGH:  return ::GetPrice(PR_CLEAR_ROUGH, 1, NULL);
-		case BT_CLEAR_ROCKY:  return ::GetPrice(PR_CLEAR_ROCKS, 1, NULL);
-		case BT_CLEAR_FIELDS: return ::GetPrice(PR_CLEAR_FIELDS, 1, NULL);
-		case BT_CLEAR_HOUSE:  return ::GetPrice(PR_CLEAR_HOUSE, 1, NULL);
+		case BT_FOUNDATION:   return ::GetPrice(PR_BUILD_FOUNDATION, 1, nullptr);
+		case BT_TERRAFORM:    return ::GetPrice(PR_TERRAFORM, 1, nullptr);
+		case BT_BUILD_TREES:  return ::GetPrice(PR_BUILD_TREES, 1, nullptr);
+		case BT_CLEAR_GRASS:  return ::GetPrice(PR_CLEAR_GRASS, 1, nullptr);
+		case BT_CLEAR_ROUGH:  return ::GetPrice(PR_CLEAR_ROUGH, 1, nullptr);
+		case BT_CLEAR_ROCKY:  return ::GetPrice(PR_CLEAR_ROCKS, 1, nullptr);
+		case BT_CLEAR_FIELDS: return ::GetPrice(PR_CLEAR_FIELDS, 1, nullptr);
+		case BT_CLEAR_HOUSE:  return ::GetPrice(PR_CLEAR_HOUSE, 1, nullptr);
 		default: return -1;
 	}
 }
diff --git a/src/script/api/script_town.cpp b/src/script/api/script_town.cpp
index 64f8e166e..9adfa5075 100644
--- a/src/script/api/script_town.cpp
+++ b/src/script/api/script_town.cpp
@@ -35,7 +35,7 @@
 
 /* static */ char *ScriptTown::GetName(TownID town_id)
 {
-	if (!IsValidTown(town_id)) return NULL;
+	if (!IsValidTown(town_id)) return nullptr;
 
 	::SetDParam(0, town_id);
 	return GetString(STR_TOWN_NAME);
@@ -45,8 +45,8 @@
 {
 	CCountedPtr<Text> counter(name);
 
-	const char *text = NULL;
-	if (name != NULL) {
+	const char *text = nullptr;
+	if (name != nullptr) {
 		text = name->GetDecodedText();
 		EnforcePreconditionEncodedText(false, text);
 		EnforcePreconditionCustomError(false, ::Utf8StringLength(text) < MAX_LENGTH_TOWN_NAME_CHARS, ScriptError::ERR_PRECONDITION_STRING_TOO_LONG);
@@ -60,7 +60,7 @@
 {
 	CCountedPtr<Text> counter(text);
 
-	EnforcePrecondition(false, text != NULL);
+	EnforcePrecondition(false, text != nullptr);
 	const char *encoded_text = text->GetEncodedText();
 	EnforcePreconditionEncodedText(false, encoded_text);
 	EnforcePrecondition(false, IsValidTown(town_id));
@@ -257,7 +257,7 @@
 	if (ScriptObject::GetCompany() == OWNER_DEITY) return false;
 	if (!IsValidTown(town_id)) return false;
 
-	return HasBit(::GetMaskOfTownActions(NULL, ScriptObject::GetCompany(), ::Town::Get(town_id)), town_action);
+	return HasBit(::GetMaskOfTownActions(nullptr, ScriptObject::GetCompany(), ::Town::Get(town_id)), town_action);
 }
 
 /* static */ bool ScriptTown::PerformTownAction(TownID town_id, TownAction town_action)
@@ -293,8 +293,8 @@
 		layout = (RoadLayout) (byte)_settings_game.economy.town_layout;
 	}
 
-	const char *text = NULL;
-	if (name != NULL) {
+	const char *text = nullptr;
+	if (name != nullptr) {
 		text = name->GetDecodedText();
 		EnforcePreconditionEncodedText(false, text);
 		EnforcePreconditionCustomError(false, ::Utf8StringLength(text) < MAX_LENGTH_TOWN_NAME_CHARS, ScriptError::ERR_PRECONDITION_STRING_TOO_LONG);
diff --git a/src/script/api/script_town.hpp b/src/script/api/script_town.hpp
index 7fdf8a6b3..302c676eb 100644
--- a/src/script/api/script_town.hpp
+++ b/src/script/api/script_town.hpp
@@ -148,7 +148,7 @@ public:
 	/**
 	 * Rename a town.
 	 * @param town_id The town to rename
-	 * @param name The new name of the town. If NULL or an empty string is passed, the town name will be reset to the default name.
+	 * @param name The new name of the town. If nullptr or an empty string is passed, the town name will be reset to the default name.
 	 * @pre IsValidTown(town_id).
 	 * @return True if the action succeeded.
 	 * @api -ai
@@ -402,7 +402,7 @@ public:
 	 * @param size The town size of the new town.
 	 * @param city True if the new town should be a city.
 	 * @param layout The town layout of the new town.
-	 * @param name The name of the new town. Pass NULL to use a random town name.
+	 * @param name The name of the new town. Pass nullptr to use a random town name.
 	 * @game @pre no company mode in scope || ScriptSettings.GetValue("economy.found_town") != 0.
 	 * @ai @pre ScriptSettings.GetValue("economy.found_town") != 0.
 	 * @game @pre no company mode in scope || size != TOWN_SIZE_LARGE.
diff --git a/src/script/api/script_tunnel.cpp b/src/script/api/script_tunnel.cpp
index 7b891f28d..a8bfcbfd3 100644
--- a/src/script/api/script_tunnel.cpp
+++ b/src/script/api/script_tunnel.cpp
@@ -102,7 +102,7 @@ static void _DoCommandReturnBuildTunnel1(class ScriptInstance *instance)
 	}
 
 	ScriptObject::SetCallbackVariable(0, start);
-	return ScriptObject::DoCommand(start, type, 0, CMD_BUILD_TUNNEL, NULL, &::_DoCommandReturnBuildTunnel1);
+	return ScriptObject::DoCommand(start, type, 0, CMD_BUILD_TUNNEL, nullptr, &::_DoCommandReturnBuildTunnel1);
 }
 
 /* static */ bool ScriptTunnel::_BuildTunnelRoad1()
@@ -114,7 +114,7 @@ static void _DoCommandReturnBuildTunnel1(class ScriptInstance *instance)
 	DiagDirection dir_1 = ::DiagdirBetweenTiles(end, start);
 	DiagDirection dir_2 = ::ReverseDiagDir(dir_1);
 
-	return ScriptObject::DoCommand(start + ::TileOffsByDiagDir(dir_1), ::DiagDirToRoadBits(dir_2) | (ScriptObject::GetRoadType() << 4), 0, CMD_BUILD_ROAD, NULL, &::_DoCommandReturnBuildTunnel2);
+	return ScriptObject::DoCommand(start + ::TileOffsByDiagDir(dir_1), ::DiagDirToRoadBits(dir_2) | (ScriptObject::GetRoadType() << 4), 0, CMD_BUILD_ROAD, nullptr, &::_DoCommandReturnBuildTunnel2);
 }
 
 /* static */ bool ScriptTunnel::_BuildTunnelRoad2()
diff --git a/src/script/api/script_vehicle.cpp b/src/script/api/script_vehicle.cpp
index f5023d12c..15bc68a97 100644
--- a/src/script/api/script_vehicle.cpp
+++ b/src/script/api/script_vehicle.cpp
@@ -29,7 +29,7 @@
 /* static */ bool ScriptVehicle::IsValidVehicle(VehicleID vehicle_id)
 {
 	const Vehicle *v = ::Vehicle::GetIfValid(vehicle_id);
-	return v != NULL && (v->owner == ScriptObject::GetCompany() || ScriptObject::GetCompany() == OWNER_DEITY) && (v->IsPrimaryVehicle() || (v->type == VEH_TRAIN && ::Train::From(v)->IsFreeWagon()));
+	return v != nullptr && (v->owner == ScriptObject::GetCompany() || ScriptObject::GetCompany() == OWNER_DEITY) && (v->IsPrimaryVehicle() || (v->type == VEH_TRAIN && ::Train::From(v)->IsFreeWagon()));
 }
 
 /* static */ ScriptCompany::CompanyID ScriptVehicle::GetOwner(VehicleID vehicle_id)
@@ -46,8 +46,8 @@
 	int num = 1;
 
 	const Train *v = ::Train::GetIfValid(vehicle_id);
-	if (v != NULL) {
-		while ((v = v->GetNextUnit()) != NULL) num++;
+	if (v != nullptr) {
+		while ((v = v->GetNextUnit()) != nullptr) num++;
 	}
 
 	return num;
@@ -71,7 +71,7 @@
 
 	EnforcePreconditionCustomError(VEHICLE_INVALID, !ScriptGameSettings::IsDisabledVehicleType((ScriptVehicle::VehicleType)type), ScriptVehicle::ERR_VEHICLE_BUILD_DISABLED);
 
-	if (!ScriptObject::DoCommand(depot, engine_id | (cargo << 24), 0, ::GetCmdBuildVeh(type), NULL, &ScriptInstance::DoCommandReturnVehicleID)) return VEHICLE_INVALID;
+	if (!ScriptObject::DoCommand(depot, engine_id | (cargo << 24), 0, ::GetCmdBuildVeh(type), nullptr, &ScriptInstance::DoCommandReturnVehicleID)) return VEHICLE_INVALID;
 
 	/* In case of test-mode, we return VehicleID 0 */
 	return 0;
@@ -104,7 +104,7 @@
 	EnforcePrecondition(false, ScriptObject::GetCompany() != OWNER_DEITY);
 	EnforcePrecondition(false, IsValidVehicle(vehicle_id));
 
-	if (!ScriptObject::DoCommand(depot, vehicle_id, share_orders, CMD_CLONE_VEHICLE, NULL, &ScriptInstance::DoCommandReturnVehicleID)) return VEHICLE_INVALID;
+	if (!ScriptObject::DoCommand(depot, vehicle_id, share_orders, CMD_CLONE_VEHICLE, nullptr, &ScriptInstance::DoCommandReturnVehicleID)) return VEHICLE_INVALID;
 
 	/* In case of test-mode, we return VehicleID 0 */
 	return 0;
@@ -120,13 +120,13 @@
 
 	const Train *v = ::Train::Get(source_vehicle_id);
 	while (source_wagon-- > 0) v = v->GetNextUnit();
-	const Train *w = NULL;
+	const Train *w = nullptr;
 	if (dest_vehicle_id != -1) {
 		w = ::Train::Get(dest_vehicle_id);
 		while (dest_wagon-- > 0) w = w->GetNextUnit();
 	}
 
-	return ScriptObject::DoCommand(0, v->index | (move_attached_wagons ? 1 : 0) << 20, w == NULL ? ::INVALID_VEHICLE : w->index, CMD_MOVE_RAIL_VEHICLE);
+	return ScriptObject::DoCommand(0, v->index | (move_attached_wagons ? 1 : 0) << 20, w == nullptr ? ::INVALID_VEHICLE : w->index, CMD_MOVE_RAIL_VEHICLE);
 }
 
 /* static */ bool ScriptVehicle::MoveWagon(VehicleID source_vehicle_id, int source_wagon, int dest_vehicle_id, int dest_wagon)
@@ -243,7 +243,7 @@
 
 	EnforcePrecondition(false, ScriptObject::GetCompany() != OWNER_DEITY);
 	EnforcePrecondition(false, IsValidVehicle(vehicle_id));
-	EnforcePrecondition(false, name != NULL);
+	EnforcePrecondition(false, name != nullptr);
 	const char *text = name->GetDecodedText();
 	EnforcePreconditionEncodedText(false, text);
 	EnforcePreconditionCustomError(false, ::Utf8StringLength(text) < MAX_LENGTH_VEHICLE_NAME_CHARS, ScriptError::ERR_PRECONDITION_STRING_TOO_LONG);
@@ -293,7 +293,7 @@
 
 /* static */ char *ScriptVehicle::GetName(VehicleID vehicle_id)
 {
-	if (!IsValidVehicle(vehicle_id)) return NULL;
+	if (!IsValidVehicle(vehicle_id)) return nullptr;
 
 	::SetDParam(0, vehicle_id);
 	return GetString(STR_VEHICLE_NAME);
@@ -410,7 +410,7 @@
 	if (!ScriptCargo::IsValidCargo(cargo)) return -1;
 
 	uint32 amount = 0;
-	for (const Vehicle *v = ::Vehicle::Get(vehicle_id); v != NULL; v = v->Next()) {
+	for (const Vehicle *v = ::Vehicle::Get(vehicle_id); v != nullptr; v = v->Next()) {
 		if (v->cargo_type == cargo) amount += v->cargo_cap;
 	}
 
@@ -423,7 +423,7 @@
 	if (!ScriptCargo::IsValidCargo(cargo)) return -1;
 
 	uint32 amount = 0;
-	for (const Vehicle *v = ::Vehicle::Get(vehicle_id); v != NULL; v = v->Next()) {
+	for (const Vehicle *v = ::Vehicle::Get(vehicle_id); v != nullptr; v = v->Next()) {
 		if (v->cargo_type == cargo) amount += v->cargo.StoredCount();
 	}
 
@@ -455,7 +455,7 @@
 	if (!IsValidVehicle(vehicle_id)) return false;
 
 	Vehicle *v = ::Vehicle::Get(vehicle_id);
-	return v->orders.list != NULL && v->orders.list->GetNumVehicles() > 1;
+	return v->orders.list != nullptr && v->orders.list->GetNumVehicles() > 1;
 }
 
 /* static */ int ScriptVehicle::GetReliability(VehicleID vehicle_id)
diff --git a/src/script/api/script_vehicle.hpp b/src/script/api/script_vehicle.hpp
index d027e1243..58a0319d0 100644
--- a/src/script/api/script_vehicle.hpp
+++ b/src/script/api/script_vehicle.hpp
@@ -115,7 +115,7 @@ public:
 	 * @param vehicle_id The vehicle to set the name for.
 	 * @param name The name for the vehicle (can be either a raw string, or a ScriptText object).
 	 * @pre IsValidVehicle(vehicle_id).
-	 * @pre name != NULL && len(name) != 0.
+	 * @pre name != nullptr && len(name) != 0.
 	 * @game @pre Valid ScriptCompanyMode active in scope.
 	 * @exception ScriptError::ERR_NAME_IS_NOT_UNIQUE
 	 * @return True if and only if the name was changed.
diff --git a/src/script/api/script_vehiclelist.cpp b/src/script/api/script_vehiclelist.cpp
index 625f0f8c4..48b290cae 100644
--- a/src/script/api/script_vehiclelist.cpp
+++ b/src/script/api/script_vehiclelist.cpp
@@ -101,7 +101,7 @@ ScriptVehicleList_SharedOrders::ScriptVehicleList_SharedOrders(VehicleID vehicle
 {
 	if (!ScriptVehicle::IsValidVehicle(vehicle_id)) return;
 
-	for (const Vehicle *v = Vehicle::Get(vehicle_id)->FirstShared(); v != NULL; v = v->NextShared()) {
+	for (const Vehicle *v = Vehicle::Get(vehicle_id)->FirstShared(); v != nullptr; v = v->NextShared()) {
 		this->AddItem(v->index);
 	}
 }
diff --git a/src/script/api/script_waypoint.cpp b/src/script/api/script_waypoint.cpp
index 91733a38e..3d121a2dc 100644
--- a/src/script/api/script_waypoint.cpp
+++ b/src/script/api/script_waypoint.cpp
@@ -20,7 +20,7 @@
 /* static */ bool ScriptWaypoint::IsValidWaypoint(StationID waypoint_id)
 {
 	const Waypoint *wp = ::Waypoint::GetIfValid(waypoint_id);
-	return wp != NULL && (wp->owner == ScriptObject::GetCompany() || ScriptObject::GetCompany() == OWNER_DEITY || wp->owner == OWNER_NONE);
+	return wp != nullptr && (wp->owner == ScriptObject::GetCompany() || ScriptObject::GetCompany() == OWNER_DEITY || wp->owner == OWNER_NONE);
 }
 
 /* static */ StationID ScriptWaypoint::GetWaypointID(TileIndex tile)
diff --git a/src/script/api/script_waypointlist.cpp b/src/script/api/script_waypointlist.cpp
index dd641a684..7e0b45a5b 100644
--- a/src/script/api/script_waypointlist.cpp
+++ b/src/script/api/script_waypointlist.cpp
@@ -32,7 +32,7 @@ ScriptWaypointList_Vehicle::ScriptWaypointList_Vehicle(VehicleID vehicle_id)
 
 	const Vehicle *v = ::Vehicle::Get(vehicle_id);
 
-	for (const Order *o = v->GetFirstOrder(); o != NULL; o = o->next) {
+	for (const Order *o = v->GetFirstOrder(); o != nullptr; o = o->next) {
 		if (o->IsType(OT_GOTO_WAYPOINT)) this->AddItem(o->GetDestination());
 	}
 }
diff --git a/src/script/api/script_window.cpp b/src/script/api/script_window.cpp
index 1252f0fc7..2766a0562 100644
--- a/src/script/api/script_window.cpp
+++ b/src/script/api/script_window.cpp
@@ -34,10 +34,10 @@
 	if (ScriptGame::IsMultiplayer()) return false;
 
 	if (number == NUMBER_ALL) {
-		return (FindWindowByClass((::WindowClass)window) != NULL);
+		return (FindWindowByClass((::WindowClass)window) != nullptr);
 	}
 
-	return FindWindowById((::WindowClass)window, number) != NULL;
+	return FindWindowById((::WindowClass)window, number) != nullptr;
 }
 
 /* static */ void ScriptWindow::Highlight(WindowClass window, uint32 number, uint8 widget, TextColour colour)
@@ -56,6 +56,6 @@
 	}
 
 	const NWidgetBase *wid = w->GetWidget<NWidgetBase>(widget);
-	if (wid == NULL) return;
+	if (wid == nullptr) return;
 	w->SetWidgetHighlight(widget, (::TextColour)colour);
 }