error handling for position

src/avatar.rs

@@ -42,7 +42,7 @@ impl From<String> for Avatar {
                     panic!("Bad room/position for avatar: {}", string);
                 }
 
-                position = Some(Position::from(room_pos[1].to_string()));
+                position = Some(Position::from(room_pos[1].to_string()).unwrap());
             } else if last_line.starts_with("NAME") {
                 name = Some(last_line.replace("NAME ", ""));
             } else if last_line.starts_with("COL") {

src/exit.rs

@@ -58,7 +58,7 @@ impl From<String> for Exit {
         // e.g. "EXT 6,4 0 10,12 FX fade_w"
         let room_position_effect: Vec<&str> = string.split_whitespace().collect();
         let room_id = from_base36(room_position_effect[0]);
-        let position = Position::from(room_position_effect[1].to_string());
+        let position = Position::from(room_position_effect[1].to_string()).unwrap();
 
         let effect = if room_position_effect.len() == 4 {
             Transition::from(room_position_effect[3])

src/position.rs

@@ -1,11 +1,13 @@
+use std::error::Error;
+
 #[derive(Debug, Eq, PartialEq)]
 pub struct Position {
     pub x: u8,
     pub y: u8,
 }
 
-impl From<String> for Position {
-    fn from(string: String) -> Position {
+impl Position {
+    pub(crate) fn from(string: String) -> Result<Position, &'static dyn Error> {
         // e.g. "2,5"
         let xy: Vec<&str> = string.split(',').collect();
         let x = xy[0].parse().unwrap();
@@ -16,7 +18,7 @@ impl From<String> for Position {
 
         let y = xy[1].parse().unwrap();
 
-        Position { x, y }
+        Ok(Position { x, y })
     }
 }
 
@@ -29,7 +31,7 @@ impl ToString for Position {
 
 #[test]
 fn test_position_from_string() {
-    assert_eq!(Position::from("4,12".to_string()), Position { x: 4, y: 12 });
+    assert_eq!(Position::from("4,12".to_string()).unwrap(), Position { x: 4, y: 12 });
 }
 
 #[test]

src/room.rs

@@ -64,13 +64,13 @@ impl From<String> for Room {
                 let item_position: Vec<&str> = last_line.split(' ').collect();
                 let item_id = item_position[0];
                 let position = item_position[1];
-                let position = Position::from(position.to_string());
+                let position = Position::from(position.to_string()).unwrap();
 
                 items.push(Instance { position, id: item_id.to_string() });
             } else if last_line.starts_with("EXT") {
                 let last_line = last_line.replace("EXT ", "");
                 let parts: Vec<&str> = last_line.split(' ').collect();
-                let position = Position::from(parts[0].to_string());
+                let position = Position::from(parts[0].to_string()).unwrap();
                 let exit = Exit::from(format!("{} {}", parts[1], parts[2]));
 
                 exits.push(ExitInstance { position, exit });
@@ -79,7 +79,7 @@ impl From<String> for Room {
                 let ending_position: Vec<&str> = last_line.split(' ').collect();
                 let ending = ending_position[0].to_string();
                 let position = ending_position[1].to_string();
-                let position = Position::from(position);
+                let position = Position::from(position).unwrap();
 
                 endings.push(Instance { position, id: ending });
             } else {

src/sprite.rs

@@ -60,7 +60,7 @@ impl From<String> for Sprite {
                     panic!("Bad room/position for sprite: {}", string);
                 }
 
-                position = Some(Position::from(room_position[1].to_string()));
+                position = Some(Position::from(room_position[1].to_string()).unwrap());
             } else if last_line.starts_with("COL") {
                 colour_id = Some(last_line.replace("COL ", "").parse().unwrap());
             } else {