refactored out Position

advent/common/position.py

@@ -0,0 +1,71 @@
+from __future__ import annotations
+from dataclasses import dataclass
+from typing import Iterator, Literal
+
+
+@dataclass(slots=True, frozen=True, order=True)
+class Position:
+    x: int
+    y: int
+
+    def __getitem__(self, index: Literal[0, 1]) -> int:
+        match index:
+            case 0: return self.x
+            case 1: return self.y
+            case _: raise IndexError()
+
+    def __iter__(self) -> Iterator[int]:
+        yield self.x
+        yield self.y
+
+    def set_x(self, x: int) -> Position:
+        return Position(x, self.y)
+
+    def set_y(self, y: int) -> Position:
+        return Position(self.x, y)
+
+    def __neg__(self) -> Position:
+        return Position(-self.x, -self.y)
+
+    def __add__(self, other: Position) -> Position:
+        return Position(self.x + other.x, self.y + other.y)
+
+    def __sub__(self, other: Position) -> Position:
+        return Position(self.x - other.x, self.y - other.y)
+
+    def __mul__(self, factor: int) -> Position:
+        return Position(self.x * factor, self.y * factor)
+
+    def taxicab_distance(self, other: Position | None = None) -> int:
+        if other is None:
+            return abs(self.x) + abs(self.y)
+        else:
+            return abs(self.x - other.x) + abs(self.y - other.y)
+
+    def right(self) -> Position:
+        return Position(self.x + 1, self.y)
+
+    def up(self) -> Position:
+        return Position(self.x, self.y - 1)
+
+    def left(self) -> Position:
+        return Position(self.x - 1, self.y)
+
+    def down(self) -> Position:
+        return Position(self.x, self.y + 1)
+
+    def unit_neighbors(self) -> Iterator[Position]:
+        yield self.right()
+        yield self.up()
+        yield self.left()
+        yield self.down()
+
+    def is_within(self, top_left: Position, bottom_right: Position) -> bool:
+        return top_left.x <= self.x < bottom_right.x and top_left.y <= self.y < bottom_right.y
+
+
+ORIGIN = Position(0, 0)
+UNIT_X = Position(1, 0)
+UNIT_Y = Position(0, 1)
+UNIT_NEG_X = Position(-1, 0)
+UNIT_NEG_Y = Position(0, -1)