1

agent/helpers.py

@@ -0,0 +1,44 @@
+# tag::helpersimport[]
+from tugo.gotypes import Point
+# end::helpersimport[]
+
+__all__ = [
+    'is_point_an_eye',
+]
+
+
+# tag::eye[]
+def is_point_an_eye(board, point, color):
+    if board.get(point) is not None:  # <1>
+        return False
+    for neighbor in point.neighbors():  # <2>
+        if board.is_on_grid(neighbor):
+            neighbor_color = board.get(neighbor)
+            if neighbor_color != color:
+                return False
+
+    friendly_corners = 0  # <3>
+    off_board_corners = 0
+    corners = [
+        Point(point.row - 1, point.col - 1),
+        Point(point.row - 1, point.col + 1),
+        Point(point.row + 1, point.col - 1),
+        Point(point.row + 1, point.col + 1),
+    ]
+    for corner in corners:
+        if board.is_on_grid(corner):
+            corner_color = board.get(corner)
+            if corner_color == color:
+                friendly_corners += 1
+        else:
+            off_board_corners += 1
+    if off_board_corners > 0:
+        return off_board_corners + friendly_corners == 4  # <4>
+    return friendly_corners >= 3  # <5>
+
+# <1> An eye is an empty point.
+# <2> All adjacent points must contain friendly stones.
+# <3> We must control 3 out of 4 corners if the point is in the middle of the board; on the edge we must control all corners.
+# <4> Point is on the edge or corner.
+# <5> Point is in the middle.
+# end::eye[]