Added queries sum, skip & take

src/cpl_query/_extension/iterable.py

@@ -1,6 +1,5 @@
 from typing import Optional, Callable, Union
 
-from cpl_query._extension.ordered_iterable import OrderedIterable
 from cpl_query.extension.ordered_iterable_abc import OrderedIterableABC
 from .._query.all import all_query
 from .._query.any import any_query
@@ -15,6 +14,8 @@ from .._query.max_min import max_query, min_query
 from .._query.order_by import order_by_query, order_by_descending_query
 from .._query.reverse import reverse_query
 from .._query.single import single_query, single_or_default_query
+from .._query.skip_take import skip_query, skip_last_query, take_query, take_last_query
+from .._query.sum import sum_query
 from .._query.where import where_query
 from cpl_query.extension.iterable_abc import IterableABC
 
@@ -40,9 +41,7 @@ class Iterable(IterableABC):
         return count_query(self, func)
 
     def distinct(self, func: Callable) -> IterableABC:
-        res = distinct_query(self, func)
-        res.__class__ = Iterable
-        return res
+        return self.__to_self(distinct_query(self, func))
 
     def element_at(self, index: int) -> any:
         return element_at_query(self, index)
@@ -73,11 +72,13 @@ class Iterable(IterableABC):
 
     def order_by(self, func: Callable) -> OrderedIterableABC:
         res = order_by_query(self, func)
+        from cpl_query._extension.ordered_iterable import OrderedIterable
         res.__class__ = OrderedIterable
         return res
 
     def order_by_descending(self, func: Callable) -> OrderedIterableABC:
         res = order_by_descending_query(self, func)
+        from cpl_query._extension.ordered_iterable import OrderedIterable
         res.__class__ = OrderedIterable
         return res
 
@@ -90,7 +91,25 @@ class Iterable(IterableABC):
     def single_or_default(self) -> Optional[any]:
         return single_or_default_query(self)
 
+    def skip(self, index: int) -> IterableABC:
+        return self.__to_self(skip_query(self, index))
+
+    def skip_last(self, index: int) -> IterableABC:
+        return self.__to_self(skip_last_query(self, index))
+
+    def sum(self, func: Callable = None) -> Union[int, float, complex]:
+        return sum_query(self, func)
+
+    def take(self, index: int) -> IterableABC:
+        return self.__to_self(take_query(self, index))
+
+    def take_last(self, index: int) -> IterableABC:
+        return self.__to_self(take_last_query(self, index))
+
     def where(self, func: Callable) -> IterableABC:
-        res = where_query(self, func)
-        res.__class__ = Iterable
-        return res
+        return self.__to_self(where_query(self, func))
+
+    @staticmethod
+    def __to_self(obj: IterableABC) -> IterableABC:
+        obj.__class__ = Iterable
+        return obj

src/cpl_query/_extension/ordered_iterable.py

@@ -1,13 +1,14 @@
-from abc import ABC
 from collections import Callable
 
+from .iterable import Iterable
 from .._query.order_by import then_by_query, then_by_descending_query
 from cpl_query.extension.ordered_iterable_abc import OrderedIterableABC
 
 
-class OrderedIterable(OrderedIterableABC, ABC):
+class OrderedIterable(Iterable, OrderedIterableABC):
 
     def __init__(self):
+        Iterable.__init__(self)
         OrderedIterableABC.__init__(self)
 
     def then_by(self, _func: Callable) -> OrderedIterableABC: