Initial

advent/common/provider.py

@@ -0,0 +1,31 @@
+from abc import abstractmethod
+from typing import Iterable, Iterator, Protocol, TypeVar
+
+
+T = TypeVar('T', covariant=True)
+
+
+class EofException(Exception):
+    pass
+
+
+class Provider(Iterator[T], Iterable[T], Protocol[T]):
+    @abstractmethod
+    def peek(self) -> T:
+        ...
+
+    @abstractmethod
+    def get(self) -> T:
+        ...
+
+    @abstractmethod
+    def finished(self) -> bool:
+        ...
+
+    def __next__(self) -> T:
+        if self.finished():
+            raise StopIteration()
+        return self.get()
+
+    def __iter__(self):
+        return self