refactor(DRAFT): start implementing Arrow*

Author: dangotbanned

narwhals/_arrow/dataframe.py

@@ -17,6 +17,7 @@
 from narwhals._arrow.utils import extract_dataframe_comparand
 from narwhals._arrow.utils import native_to_narwhals_dtype
 from narwhals._arrow.utils import select_rows
+from narwhals._compliant import EagerDataFrame
 from narwhals._expression_parsing import ExprKind
 from narwhals._expression_parsing import evaluate_into_exprs
 from narwhals.dependencies import is_numpy_array_1d
@@ -71,7 +72,7 @@
 from narwhals.typing import CompliantLazyFrame
 
 
-class ArrowDataFrame(CompliantDataFrame["ArrowSeries"], CompliantLazyFrame):
+class ArrowDataFrame(EagerDataFrame["ArrowSeries"], CompliantLazyFrame):
     # --- not in the spec ---
     def __init__(
         self: Self,

narwhals/_arrow/expr.py

@@ -13,7 +13,7 @@
 from narwhals._arrow.expr_name import ArrowExprNameNamespace
 from narwhals._arrow.expr_str import ArrowExprStringNamespace
 from narwhals._arrow.series import ArrowSeries
-from narwhals._compliant import CompliantExpr
+from narwhals._compliant import EagerExpr
 from narwhals._expression_parsing import ExprKind
 from narwhals._expression_parsing import evaluate_output_names_and_aliases
 from narwhals._expression_parsing import is_scalar_like
@@ -33,7 +33,7 @@
     from narwhals.utils import Version
 
 
-class ArrowExpr(CompliantExpr["ArrowDataFrame", ArrowSeries]):
+class ArrowExpr(EagerExpr["ArrowDataFrame", ArrowSeries]):
     _implementation: Implementation = Implementation.PYARROW
 
     def __init__(

narwhals/_arrow/namespace.py

@@ -25,7 +25,7 @@
 from narwhals._arrow.utils import horizontal_concat
 from narwhals._arrow.utils import nulls_like
 from narwhals._arrow.utils import vertical_concat
-from narwhals._compliant import CompliantNamespace
+from narwhals._compliant import EagerNamespace
 from narwhals._expression_parsing import combine_alias_output_names
 from narwhals._expression_parsing import combine_evaluate_output_names
 from narwhals.utils import Implementation
@@ -48,7 +48,15 @@
     _Scalar: TypeAlias = Any
 
 
-class ArrowNamespace(CompliantNamespace[ArrowDataFrame, ArrowSeries]):
+class ArrowNamespace(EagerNamespace[ArrowDataFrame, ArrowSeries]):
+    @property
+    def _expr(self) -> type[ArrowExpr]:
+        return ArrowExpr
+
+    @property
+    def _series(self) -> type[ArrowSeries]:
+        return ArrowSeries
+
     def _create_expr_from_callable(
         self: Self,
         func: Callable[[ArrowDataFrame], Sequence[ArrowSeries]],

narwhals/_arrow/series.py

@@ -25,8 +25,8 @@
 from narwhals._arrow.utils import native_to_narwhals_dtype
 from narwhals._arrow.utils import nulls_like
 from narwhals._arrow.utils import pad_series
+from narwhals._compliant import EagerSeries
 from narwhals.exceptions import InvalidOperationError
-from narwhals.typing import CompliantSeries
 from narwhals.utils import Implementation
 from narwhals.utils import generate_temporary_column_name
 from narwhals.utils import import_dtypes_module
@@ -94,7 +94,7 @@ def maybe_extract_py_scalar(value: Any, return_py_scalar: bool) -> Any:  # noqa:
     return value
 
 
-class ArrowSeries(CompliantSeries):
+class ArrowSeries(EagerSeries["ArrowChunkedArray"]):
     def __init__(
         self: Self,
         native_series: ArrowChunkedArray,
@@ -111,6 +111,10 @@ def __init__(
         validate_backend_version(self._implementation, self._backend_version)
         self._broadcast = False
 
+    @property
+    def native(self) -> ArrowChunkedArray:
+        return self._native_series
+
     def _change_version(self: Self, version: Version) -> Self:
         return self.__class__(
             self._native_series,