dedupe optional line for tile

src/tile.rs

@@ -1,4 +1,4 @@
-use crate::{AnimationFrames, from_base36, ToBase36};
+use crate::{AnimationFrames, from_base36, ToBase36, optional_data_line};
 use crate::image::Image;
 use crate::mock;
 
@@ -10,6 +10,12 @@ pub struct Tile {
     pub animation_frames: Vec<Image>,
 }
 
+impl Tile {
+    fn name_line(&self) -> String {
+        optional_data_line("NAME", self.name.as_ref())
+    }
+}
+
 impl From<String> for Tile {
     #[inline]
     fn from(string: String) -> Tile {
@@ -52,7 +58,7 @@ impl ToString for Tile {
             "TIL {}\n{}{}{}",
             self.id.to_base36(),
             self.animation_frames.to_string(),
-            if self.name.as_ref().is_some() { format!("\nNAME {}", self.name.as_ref().unwrap())} else {"".to_string() },
+            self.name_line(),
             if self.wall {"\nWAL true"} else {""}
         )
     }