function for optional lines of game data

src/lib.rs

@@ -30,6 +30,7 @@ use room::Room;
 use sprite::Sprite;
 use tile::Tile;
 use variable::Variable;
+use std::fmt::Display;
 
 #[derive(Debug, Eq, PartialEq)]
 pub struct Instance {
@@ -95,3 +96,18 @@ impl ToBase36 for u64 {
 fn test_to_base36() {
     assert_eq!((37 as u64).to_base36(), "11");
 }
+
+/// e.g. `\nNAME DLG_0`
+fn optional_data_line<T: Display>(label: &str, item: Option<T>) -> String {
+    if item.is_some() {
+        format!("\n{} {}", label, item.unwrap())
+    } else {
+        "".to_string()
+    }
+}
+
+#[test]
+fn test_optional_data_line() {
+    let output = optional_data_line("NAME", mock::item().name);
+    assert_eq!(output, "\nNAME door".to_string());
+}