dungeon: add step_by function for Pos, and rename step to step_by for FPos

1 files changed, 36 insertions, 8 deletions

diff --git a/dungeon/src/pos.rs b/dungeon/src/pos.rs
index e2d449c..8f1f8dd 100644
--- a/dungeon/src/pos.rs
+++ b/dungeon/src/pos.rs
@@ -219,13 +219,41 @@ impl Pos {
 	/// ```
 	#[must_use]
 	pub const fn step(self, dir: Direction) -> Option<Self> {
-		use Direction as D;
+		self.step_by(dir, 1)
+	}
+
+	/// Steps `Pos` a given ammount in the `Direction` `dir`.
+	///
+	/// Returns `None` if the position goes out of the map.
+	///
+	/// # Examples
+	///
+	/// ```
+	/// use dungeon::{Direction, Pos};
+	///
+	/// let pos = Pos::new(0, 1).unwrap();
+	/// let new_pos = pos.step_by(Direction::South, 3);
+	/// assert_eq!(new_pos, Pos::new(0, 4));
+	/// ```
+	///
+	/// ```
+	/// use dungeon::{Direction, Pos};
+	///
+	/// let pos = Pos::new(1, 1).unwrap();
+	/// let new_pos = pos.step_by(Direction::West, 2);
+	/// assert!(new_pos.is_none());
+	/// ```
+	#[must_use]
+	pub const fn step_by(self, dir: Direction, amt: u16) -> Option<Self> {
 		let (x, y) = self.xy();
+		if amt > MAP_SIZE {
+			return None;
+		}
 		match dir {
-			D::North if y > 0 => Self::new(x, y - 1),
-			D::South => Self::new(x, y + 1),
-			D::East => Self::new(x + 1, y),
-			D::West if x > 0 => Self::new(x - 1, y),
+			Direction::North if y >= amt => Self::new(x, y - amt),
+			Direction::South => Self::new(x, y + amt),
+			Direction::East => Self::new(x + amt, y),
+			Direction::West if x >= amt => Self::new(x - amt, y),
 			_ => None,
 		}
 	}
@@ -399,7 +427,7 @@ impl FPos {
 	/// use dungeon::{Direction, FPos};
 	///
 	/// let fpos = FPos::new(0.0, 1.0);
-	/// let new_fpos = fpos.step(Direction::North, 0.3);
+	/// let new_fpos = fpos.step_by(Direction::North, 0.3);
 	/// assert!(new_fpos.is_some());
 	/// ```
 	///
@@ -407,11 +435,11 @@ impl FPos {
 	/// use dungeon::{Direction, FPos};
 	///
 	/// let fpos = FPos::new(0.0, 0.0);
-	/// let new_fpos = fpos.step(Direction::North, 5.0);
+	/// let new_fpos = fpos.step_by(Direction::North, 5.0);
 	/// assert!(new_fpos.is_none());
 	/// ```
 	#[must_use]
-	pub fn step(self, dir: Direction, amt: f32) -> Option<Self> {
+	pub fn step_by(self, dir: Direction, amt: f32) -> Option<Self> {
 		use Direction as D;
 		let (mut x, mut y) = self.xy();
 		match dir {