setitem

src/daglib/dag.py

@@ -38,13 +38,13 @@ class DAG(Generic[T], MutableMapping[T, MutableSet[T]]):
         dagset = DAGSet(self._succ.get(u))
 
         def on_add(v: T) -> None:
-            self._succ[u].add(v)
+            self._succ[u] |= {v}
-            self._pred[v].add(u)
+            self._pred[v] |= {u}
             print(f"Adding edge {u} -> {v}")
 
         def on_remove(v: T) -> None:
-            self._succ[u].remove(v)
+            self._succ[u] -= {v}
-            self._pred[v].remove(u)
+            self._pred[v] -= {u}
             print(f"Removing edge {u} -> {v}")
 
         dagset.on_add = on_add
@@ -52,10 +52,21 @@ class DAG(Generic[T], MutableMapping[T, MutableSet[T]]):
         return dagset
 
     def __setitem__(self, u: T, vs: Iterable[T]) -> None:
-        view = DAGSet(self, u)
+        match vs:
-        view.clear()
+            case set():
-        view |= vs  # uses our in-place operator
+                self._succ[u] |= vs
-
+                for v in vs:
+                    self._pred[v] |= {u}
+            case str():
+                self._succ[u] |= {vs}
+                self._pred[vs] |= {u}
+            case Iterable():
+                self._succ[u] |= set(vs)
+                for v in vs:
+                    self._pred[v] |= {u}
+            case _:
+                raise TypeError(f"Expected set or iterable, got {type(vs).__name__}")
+        
     def __delitem__(self, u: T) -> None:
         self.discard_node(u)