1 files changed, 21 insertions, 9 deletions

diff --git a/7/solution.py b/7/solution.py
index 77a1391..6eee284 100644
--- a/7/solution.py
+++ b/7/solution.py
@@ -15,34 +15,44 @@ class U16:
         return U16(self.value << other.value)
     def __str__(self):
         return str(self.value)
+    def __repr__(self):
+        return f'{self.value}'
 
 class Node:
-    _value: U16 = None
+    _value: U16 | None = None
     @property
     def value(self) -> U16:
-        if not self._value:
+        if self._value is None:
             self._value = self.eval()
         return self._value
-    def eval(self, net: dict[Node]) -> U16:
-        return self.eval()
-    @absrtactmethod
+    @abstractmethod
     def eval(self) -> U16:
         pass
+    @abstractmethod
+    def __repr__(self) -> str:
+        pass
 
 class Reference(Node):
-    def __init__(self, name: str):
+    def __init__(self, net: dict[Node], name: str):
+        self.net = net
         self.name = name
-    def eval(self, net: dict[Node]) -> U16:
-        return net[self.name].value
+    def eval(self) -> U16:
+        return self.net[self.name].value
+    def __repr__(self) -> str:
+        return f'Reference({self.name})'
 
 class Constant(Node):
     def __init__(self, value):
         self._value = value
+    def __repr__(self) -> str:
+        return f'Constant({self.value})'
 
 class BinaryOp(Node):
     def __init__(self, left, right):
         self.left = left
         self.right = right
+    def __repr__(self) -> str:
+        return f'{self.__class__.__name__}({self.left}, {self.right})'
 
 class And(BinaryOp):
     def eval(self) -> U16:
@@ -65,6 +75,8 @@ class Not(Node):
         self.node = node
     def eval(self):
         return ~self.node.value
+    def __repr__(self) -> str:
+        return 'Not({self.node})'
 
 def parse_expr(net: dict[Node], expr: str) -> Node:
     parts = expr.split(' ')
@@ -112,4 +124,4 @@ if __name__ == '__main__':
     with open('input') as f:
         inp = [line.strip() for line in f]
     print(part1(inp))
-    print(part2(inp))
\ No newline at end of file
+    print(part2(inp))