wip unbroken

narwhals/pandas_like/dataframe.py

@@ -11,7 +11,6 @@
 from narwhals.pandas_like.utils import horizontal_concat
 from narwhals.pandas_like.utils import validate_dataframe_comparand
 from narwhals.spec import DataFrame as DataFrameT
-from narwhals.spec import IntoExpr
 from narwhals.spec import LazyFrame as LazyFrameProtocol
 from narwhals.spec import Namespace as NamespaceProtocol
 
@@ -23,6 +22,7 @@
     from narwhals.pandas_like.group_by_object import GroupBy
     from narwhals.pandas_like.group_by_object import LazyGroupBy
     from narwhals.pandas_like.namespace import Namespace
+    from narwhals.pandas_like.utils import IntoExpr
 
 
 class DataFrame(DataFrameT):

narwhals/pandas_like/expr.py

@@ -4,23 +4,23 @@
 from typing import Any
 from typing import Callable
 
-from narwhals.pandas_like.series import Series
 from narwhals.pandas_like.utils import register_expression_call
-from narwhals.spec import DataFrame as DataFrameT
 from narwhals.spec import Expr as ExprT
 from narwhals.spec import ExprStringNamespace as ExprStringNamespaceT
-from narwhals.spec import LazyFrame as LazyFrameProtocol
 from narwhals.spec import Namespace as NamespaceProtocol
-from narwhals.spec import Series as SeriesProtocol
 
 if TYPE_CHECKING:
     from typing_extensions import Self
 
+    from narwhals.pandas_like.dataframe import DataFrame
+    from narwhals.pandas_like.dataframe import LazyFrame
+    from narwhals.pandas_like.series import Series
+
 
 class Expr(ExprT):
     def __init__(  # noqa: PLR0913
         self,
-        call: Callable[[DataFrameT | LazyFrameProtocol], list[SeriesProtocol]],
+        call: Callable[[DataFrame | LazyFrame], list[Series]],
         *,
         depth: int | None,
         function_name: str | None,
@@ -50,6 +50,8 @@ def __repr__(self) -> str:
     def from_column_names(
         cls: type[Self], *column_names: str, implementation: str
     ) -> Self:
+        from narwhals.pandas_like.series import Series
+
         return cls(
             lambda df: [
                 Series(
@@ -197,7 +199,7 @@ def alias(self, name: str) -> Self:
         if self._depth is None:
             msg = "Unreachable code, please report a bug"
             raise AssertionError(msg)
-        return Expr(
+        return self.__class__(
             lambda df: [series.alias(name) for series in self.call(df)],
             depth=self._depth,
             function_name=self._function_name,
@@ -217,6 +219,8 @@ def __init__(self, expr: ExprT) -> None:
 
     def ends_with(self, suffix: str) -> Expr:
         # TODO make a register_expression_call for namespaces
+        from narwhals.pandas_like.series import Series
+
         return Expr(
             lambda df: [
                 Series(
@@ -234,6 +238,8 @@ def ends_with(self, suffix: str) -> Expr:
         )
 
     def strip_chars(self, characters: str = " ") -> Expr:
+        from narwhals.pandas_like.series import Series
+
         return Expr(
             lambda df: [
                 Series(

narwhals/pandas_like/namespace.py

@@ -14,11 +14,8 @@
 from narwhals.pandas_like.utils import parse_into_exprs
 from narwhals.pandas_like.utils import series_from_iterable
 from narwhals.spec import AnyDataFrame
-from narwhals.spec import DataFrame as DataFrameT
 from narwhals.spec import IntoExpr
-from narwhals.spec import LazyFrame as LazyFrameProtocol
 from narwhals.spec import Namespace as NamespaceProtocol
-from narwhals.spec import Series as SeriesProtocol
 
 
 class Namespace(NamespaceProtocol):
@@ -109,7 +106,7 @@ def len(self) -> Expr:
 
     def _create_expr_from_callable(  # noqa: PLR0913
         self,
-        func: Callable[[DataFrameT | LazyFrameProtocol], list[SeriesProtocol]],
+        func: Callable[[DataFrame | LazyFrame], list[Series]],
         *,
         depth: int,
         function_name: str | None,
@@ -125,9 +122,7 @@ def _create_expr_from_callable(  # noqa: PLR0913
             implementation=self._implementation,
         )
 
-    def _create_series_from_scalar(
-        self, value: Any, series: SeriesProtocol
-    ) -> SeriesProtocol:
+    def _create_series_from_scalar(self, value: Any, series: Series) -> Series:
         return Series(
             series_from_iterable(
                 [value],
@@ -139,7 +134,7 @@ def _create_series_from_scalar(
             implementation=self._implementation,
         )
 
-    def _create_expr_from_series(self, series: SeriesProtocol) -> Expr:
+    def _create_expr_from_series(self, series: Series) -> Expr:
         return Expr(
             lambda _df: [series],
             depth=0,

narwhals/pandas_like/series.py

@@ -49,8 +49,8 @@ def __repr__(self) -> str:  # pragma: no cover
             + "┘\n"
         )
 
-    def _from_series(self, series: Any) -> Series:
-        return Series(
+    def _from_series(self, series: Any) -> Self:
+        return self.__class__(
             series.rename(series.name, copy=False),
             api_version=self.api_version,
             implementation=self._implementation,