Import habits upon creating habitmgr.

src/habitmgr.rs

@@ -55,23 +55,27 @@ impl HabitMgr
 								 habits_path.display(), e);
 				});
 		}
-		Self
-		{
-			habits: Vec::new(),
-			habits_path,
-		}
-	}
 
-	fn import_habits(&mut self)
-	{
+		/*
+		 * The list of active habits is necessary for all functions, thus they're
+		 * imported here, allowing member functions which only wish to access
+		 * information to be constant.
+		 */
 		let habits_file = OpenOptions::new()
 			.read(true)
-			.open(&self.habits_path)
+			.open(&habits_path)
 			.unwrap_or_else(|e| {
-				panic!("Error opening file {}:\n{}", self.habits_path.display(), e);
+				panic!("Error opening file {}:\n{}", habits_path.display(), e);
 			});
 		let habits_reader = BufReader::new(&habits_file);
-		self.habits = serde_json::from_reader(habits_reader).unwrap();
+
+		let habits:Vec<Habit> = serde_json::from_reader(habits_reader).unwrap();
+
+		Self
+		{
+			habits,
+			habits_path,
+		}
 	}
 
 	fn export_habits(&self)
@@ -93,7 +97,6 @@ impl HabitMgr
 
 	pub fn add(&mut self, name:String, bad:bool, weight:u8, _days:String)
 	{
-		self.import_habits();
 		self.habits.push(Habit::new(name.clone(), bad, weight));
 		self.export_habits();
 
@@ -102,15 +105,13 @@ impl HabitMgr
 
 	pub fn delete(&mut self, id:usize)
 	{
-		self.import_habits();
 		let old_habit = self.habits.remove(id);
 		self.export_habits();
 		println!("Removed habit {}", old_habit.get_name());
 	}
 
-	pub fn habit_info(&mut self, id:usize)
+	pub fn habit_info(&self, id:usize)
 	{
-		self.import_habits();
 		let habit = &self.habits[id];
 		println!("Name: {}", habit.get_name());
 		println!("ID: {}", id);
@@ -125,7 +126,6 @@ impl HabitMgr
 						 weight:Option<u8>,
 						 _days:Option<String>)
 	{
-		self.import_habits();
 		if name.is_some()
 		{
 			self.habits[id].set_name(name.unwrap());
@@ -142,9 +142,8 @@ impl HabitMgr
 		self.export_habits();
 	}
 
-	pub fn list(&mut self, _all:bool)
+	pub fn list(&self, _all:bool)
 	{
-		self.import_habits();
 		if self.habits.is_empty()
 		{
 			println!("There are no habits. Add one!");