"new id" and "add thing" functions

src/game.rs

@@ -393,6 +393,18 @@ impl Game {
         new_unique_id(ids)
     }
 
+    pub fn new_sprite_id(&self) -> String {
+        new_unique_id(self.sprite_ids())
+    }
+
+    pub fn new_room_id(&self) -> String {
+        new_unique_id(self.room_ids())
+    }
+
+    pub fn new_item_id(&self) -> String {
+        new_unique_id(self.item_ids())
+    }
+
     /// adds a tile safely and returns the new tile ID
     #[inline]
     pub fn add_tile(&mut self, mut tile: Tile) -> String {
@@ -402,6 +414,24 @@ impl Game {
         new_id
     }
 
+    /// adds a sprite safely and returns the new sprite ID
+    #[inline]
+    pub fn add_sprite(&mut self, mut sprite: Sprite) -> String {
+        let new_id = self.new_sprite_id();
+        sprite.id = new_id.clone();
+        self.sprites.push(sprite);
+        new_id
+    }
+
+    /// adds a sprite safely and returns the new sprite ID
+    #[inline]
+    pub fn add_item(&mut self, mut item: Item) -> String {
+        let new_id = self.new_item_id();
+        item.id = new_id.clone();
+        self.items.push(item);
+        new_id
+    }
+
     #[inline]
     fn version_line(&self) -> String {
         if self.version.is_some() {