[states] Make ALL_POSITIONS public

solve/states/base.py

@@ -10,15 +10,15 @@
 RIGHT: Literal['right'] = 'right'
 type PositionsType = Literal['left', 'middle', 'right']
 
-_POSITIONS = {LEFT, MIDDLE, RIGHT}
+ALL_POSITIONS = {LEFT: None, MIDDLE: None, RIGHT: None}
 _POSITIONS_MSG = f'{LEFT!r}, {MIDDLE!r} or {RIGHT!r}'
 
 
 def is_position(s: str, /) -> TypeGuard[PositionsType]:
     """
     Returns ``True`` if a string is a valid position.
     """
-    return s in _POSITIONS
+    return s in ALL_POSITIONS
 
 
 class PMove(Protocol):
@@ -125,7 +125,7 @@ def __init__(self, /, left: S, middle: S, right: S, moves_made: tuple[M, ...] =
         self.moves_made = moves_made
 
     # region Verify that constructor and slots have POSITIONS
-    assert set(__slots__) >= _POSITIONS, f'encounter state must have position attributes'
+    assert set(__slots__) >= ALL_POSITIONS.keys(), f'encounter state must have position attributes'
 
     signature_ = signature(__init__)
     kwargs = {
@@ -134,7 +134,7 @@ def __init__(self, /, left: S, middle: S, right: S, moves_made: tuple[M, ...] =
         if p.kind == p.KEYWORD_ONLY or p.kind == p.POSITIONAL_OR_KEYWORD
         }
 
-    assert kwargs >= _POSITIONS, f'encounter state must have position keyword arguments'
+    assert kwargs >= ALL_POSITIONS.keys(), f'encounter state must have position keyword arguments'
     del signature_, kwargs
     # endregion
 
@@ -180,6 +180,7 @@ def __repr__(self, /) -> str:
     'LEFT',
     'MIDDLE',
     'RIGHT',
+    'ALL_POSITIONS',
     'PositionsType',
     'is_position',
     'State',

solve/states/rooms.py

@@ -184,7 +184,7 @@ def init_rooms_from_players(
         for p in players
         if p.their_shape == i
         }
-    aliases = dict(zip((LEFT, MIDDLE, RIGHT), (inner2person[i].alias for i in inner_shapes)))
+    aliases = dict(zip(ALL_POSITIONS, (inner2person[i].alias for i in inner_shapes)))
     other = tuple(inner2person[i].other_shape for i in inner_shapes)
     state = init_rooms(
         left_inner_shape=inner_shapes[0],