undo/redo editing sign text

src/scenedit/scen.townout.cpp

@@ -425,16 +425,18 @@ void edit_placed_item(short which_i) {
 
 static bool edit_sign_event_filter(cDialog& me, sign_loc_t& which_sign) {
 	if(!me.toast(true)) return true;
-	which_sign.text = me["text"].getText();
-#if 0 // TODO: Apparently there used to be left/right buttons on this dialog.
-	if(item_hit == 3)
-		which_sign--;
-	else which_sign++;
-	if(which_sign < 0)
-		which_sign = (editing_town) ? 14 : 7;
-	if(which_sign > (editing_town) ? 14 : 7)
-		which_sign = 0;
-#endif
+
+	std::string cur_text = me["text"].getText();
+	if(which_sign.text != cur_text){
+		undo_list.add(action_ptr(new aEditSignText(which_sign, which_sign.text, cur_text)));
+		update_edit_menu();
+		which_sign.text = cur_text;
+	}
+
+	// There used to be left/right buttons in the sign editor dialog, but there shouldn't be,
+	// because left/right is not a meaningful index to let the designer know which sign they're editing.
+	// I removed the unused code.
+
 	return true;
 }
 

src/scenedit/scen.undo.cpp

@@ -244,3 +244,19 @@ bool aPlaceEraseCreature::redo_me() {
 	}
 	return true;
 }
+
+bool aEditSignText::undo_me() {
+	cArea* cur_area = get_current_area();
+	auto& signs = cur_area->sign_locs;
+	auto iter = std::find(signs.begin(), signs.end(), area.where);
+	iter->text = old_text;
+	return true;
+}
+
+bool aEditSignText::redo_me() {
+	cArea* cur_area = get_current_area();
+	auto& signs = cur_area->sign_locs;
+	auto iter = std::find(signs.begin(), signs.end(), area.where);
+	iter->text = new_text;
+	return true;
+}

src/scenedit/scen.undo.hpp

@@ -35,6 +35,7 @@ class cTerrainAction : public cAction {
 public:
 	cTerrainAction(std::string name, short town_num, location where, bool reversed = false);
 	cTerrainAction(std::string name, location out_sec, location where, bool reversed = false);
+	// Construct cTerrainAction in the current town/outdoor section
 	cTerrainAction(std::string name, location where, bool reversed = false);
 	void undo();
 	void redo();
@@ -43,6 +44,7 @@ public:
 private:
 	/// Show where the change happened
 	void showChangeSite();
+protected:
 	area_ref_t area;
 };
 
@@ -92,6 +94,17 @@ public:
 	aPlaceEraseCreature(std::string name, bool place, size_t index, cTownperson creature);
 };
 
+/// Action which edits sign text
+class aEditSignText : public cTerrainAction {
+	std::string old_text;
+	std::string new_text;
+	bool undo_me() override;
+	bool redo_me() override;
+public:
+	aEditSignText(location loc, std::string old_text, std::string new_text) :
+		cTerrainAction("Edit Sign Text", loc), old_text(old_text), new_text(new_text) {}
+};
+
 /// Action which adds a new town to the end of the list, or deletes the last one
 class aCreateDeleteTown : public cAction {
 	bool created;