Add back Spin type in new submodule 'input'

mino/src/input.rs

@@ -0,0 +1,65 @@
+//! Data structures and operations for game inputs, particularly ones that induce
+//! movements to the current piece.
+
+use crate::piece::Rot;
+
+/// Represents a rotating operation. Includes 180 degree "flips", which are non-standard
+/// for tetris but exist in many unofficial iterations of the game.
+///
+/// Rotations may be performed on [rotation states](Rot) using the [addition
+/// operator](core::ops::Add).
+///
+/// ```
+/// # use mino::{piece::Rot, input::Spin};
+/// assert_eq!(Rot::N + Spin::Cw, Rot::E);
+/// ```
+#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Debug)]
+#[repr(i8)]
+pub enum Spin {
+    /// Clockwise.
+    Cw = 1,
+    /// 180 degrees.
+    Flip = 2,
+    /// Counterclockwise.
+    Ccw = -1,
+}
+
+impl core::ops::Add<Spin> for Rot {
+    type Output = Rot;
+    fn add(self, r: Spin) -> Rot {
+        (self as i8).wrapping_add(r as i8).into()
+    }
+}
+
+impl core::ops::AddAssign<Spin> for Rot {
+    fn add_assign(&mut self, r: Spin) {
+        *self = *self + r;
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_angle_rotate() {
+        use Rot::*;
+        use Spin::*;
+        assert_eq!(N + Cw, E);
+        assert_eq!(N + Ccw, W);
+        assert_eq!(N + Flip, S);
+        assert_eq!(E + Cw, S);
+        assert_eq!(E + Ccw, N);
+        assert_eq!(E + Flip, W);
+        assert_eq!(S + Cw, W);
+        assert_eq!(S + Ccw, E);
+        assert_eq!(S + Flip, N);
+        assert_eq!(W + Cw, N);
+        assert_eq!(W + Ccw, S);
+        assert_eq!(W + Flip, E);
+
+        let mut r = N;
+        r += Ccw;
+        assert_eq!(r, W);
+    }
+}

mino/src/lib.rs

@@ -1,5 +1,6 @@
 #![no_std]
 
+pub mod input;
 pub mod matrix;
 pub mod piece;