feat: ensure Iter is an iterator.

Fixes #71

iterpy/_iter.py

@@ -17,22 +17,22 @@
 
 class Iter(Generic[T]):
     def __init__(self, iterable: Iterable[T]) -> None:
-        self._iterator: Iterator[T] = iter(iterable)
+        self.__consumable_iterator: Iterator[T] = iter(iterable)
 
     @property
-    def _non_consumable(self) -> Iterator[T]:
-        return deepcopy(self._iterator)
+    def _iterator(self) -> Iterator[T]:
+        return deepcopy(self.__consumable_iterator)
 
     def __getitem__(self, index: int | slice) -> T | "Iter[T]":
         if isinstance(index, int) and index >= 0:
             try:
-                return list(self._non_consumable)[index]
+                return list(self._iterator)[index]
             except StopIteration:
                 raise IndexError("Index out of range") from None
         elif isinstance(index, slice):
             return Iter(
                 islice(
-                    self._non_consumable,
+                    self._iterator,
                     index.start,
                     index.stop,
                     index.step,
@@ -44,6 +44,9 @@ def __getitem__(self, index: int | slice) -> T | "Iter[T]":
             )
 
     ### Reductions
+    def reduce(self, func: Callable[[T, T], T]) -> T:
+        return reduce(func, self._iterator)
+
     def count(self) -> int:
         return sum(1 for _ in self._iterator)
 
@@ -54,7 +57,7 @@ def to_list(self) -> list[T]:
     def to_tuple(self) -> tuple[T, ...]:
         return tuple(self._iterator)  # pragma: no cover
 
-    def to_iterator(self) -> Iterator[T]:
+    def to_consumable(self) -> Iterator[T]:
         return iter(self._iterator)  # pragma: no cover
 
     def to_set(self) -> set[T]:
@@ -81,9 +84,6 @@ def pmap(
     def filter(self, func: Callable[[T], bool]) -> "Iter[T]":  # noqa: A003
         return Iter(filter(func, self._iterator))
 
-    def reduce(self, func: Callable[[T, T], T]) -> T:
-        return reduce(func, self._iterator)
-
     def groupby(
         self, func: Callable[[T], str]
     ) -> "Iter[tuple[str, list[T]]]":

iterpy/_iter.pyi

@@ -27,7 +27,7 @@ class Iter(Generic[T]):
     def count(self) -> int: ...
     def to_list(self) -> list[T]: ...
     def to_tuple(self) -> tuple[T, ...]: ...
-    def to_iterator(self) -> Iterator[T]: ...
+    def to_consumable(self) -> Iterator[T]: ...
     def to_set(self) -> set[T]: ...
     def map(self, func: Callable[[T], S]) -> Iter[S]:  # noqa: A003
         ...

iterpy/benchmark/query_1/iterators_q1.py

@@ -105,7 +105,7 @@ def main_iterator(data: Sequence[Item]) -> Sequence[CategorySummary]:
 
     summaries = [
         summarise_category(group, rows=values)
-        for group, values in mapping.to_iterator()
+        for group, values in mapping.to_consumable()
     ]
 
     return summaries

iterpy/test_iter.py

@@ -73,6 +73,18 @@ def test_getitem():
     assert test_iterator[0:2].to_list() == [1, 2]
 
 
+def test_iteration():
+    test_iterator = Iter([1, 2, 3])
+    for i in test_iterator.to_consumable():
+        assert i in [1, 2, 3]
+
+
+def test_statefulness():
+    test_iterator = Iter([1, 2, 3])
+    assert test_iterator.to_list() == [1, 2, 3]
+    assert test_iterator.to_list() == [1, 2, 3]
+
+
 def test_flatten():
     test_input: list[list[int]] = [[1, 2], [3, 4]]
     iterator = Iter(test_input)