refactor: Move ExprDispatch to column.py

Author: dangotbanned

narwhals/_plan/arrow/expr.py

@@ -9,9 +9,10 @@
 from narwhals._plan.arrow import functions as fn
 from narwhals._plan.arrow.series import ArrowSeries as Series
 from narwhals._plan.arrow.typing import ChunkedOrScalarAny, NativeScalar, StoresNativeT_co
+from narwhals._plan.compliant.column import ExprDispatch
 from narwhals._plan.compliant.typing import namespace
 from narwhals._plan.expressions import NamedIR
-from narwhals._plan.protocols import EagerExpr, EagerScalar, ExprDispatch
+from narwhals._plan.protocols import EagerExpr, EagerScalar
 from narwhals._utils import (
     Implementation,
     Version,

narwhals/_plan/compliant/column.py

@@ -1,16 +1,24 @@
 from __future__ import annotations
 
-from collections.abc import Sequence, Sized
+from collections.abc import Sized
 from typing import TYPE_CHECKING, Protocol
 
 from narwhals._plan.common import flatten_hash_safe
-from narwhals._plan.compliant.typing import LengthT, SeriesT
+from narwhals._plan.compliant.typing import (
+    FrameT_contra,
+    LengthT,
+    NamespaceT_co,
+    R_co,
+    SeriesT,
+    StoresVersion,
+)
 
 if TYPE_CHECKING:
     from collections.abc import Iterator, Sequence
 
     from typing_extensions import Self
 
+    from narwhals._plan import expressions as ir
     from narwhals._plan.typing import OneOrIterable
 
 
@@ -74,3 +82,18 @@ def _length_required(
         max_length = cls._length_max(lengths)
         required = any(len_ != max_length for len_ in lengths)
         return max_length if required else None
+
+
+class ExprDispatch(StoresVersion, Protocol[FrameT_contra, R_co, NamespaceT_co]):
+    @classmethod
+    def from_ir(cls, node: ir.ExprIR, frame: FrameT_contra, name: str) -> R_co:
+        obj = cls.__new__(cls)
+        obj._version = frame.version
+        return node.dispatch(obj, frame, name)
+
+    @classmethod
+    def from_named_ir(cls, named_ir: ir.NamedIR[ir.ExprIR], frame: FrameT_contra) -> R_co:
+        return cls.from_ir(named_ir.expr, frame, named_ir.name)
+
+    # NOTE: Needs to stay `covariant` and never be used as a parameter
+    def __narwhals_namespace__(self) -> NamespaceT_co: ...

narwhals/_plan/compliant/typing.py

@@ -7,6 +7,7 @@
 if TYPE_CHECKING:
     from typing_extensions import TypeAlias
 
+    from narwhals._plan.compliant.column import ExprDispatch
     from narwhals._plan.compliant.dataframe import (
         CompliantBaseFrame,
         CompliantDataFrame,
@@ -20,7 +21,6 @@
         CompliantScalar,
         EagerExpr,
         EagerScalar,
-        ExprDispatch,
         LazyExpr,
         LazyScalar,
     )

narwhals/_plan/protocols.py

@@ -8,8 +8,6 @@
 from narwhals._plan.compliant.typing import (
     FrameT_contra,
     LengthT,
-    NamespaceT_co,
-    R_co,
     SeriesT,
     SeriesT_co,
     StoresVersion,
@@ -23,7 +21,6 @@
     from narwhals._plan.expressions import (
         BinaryExpr,
         FunctionExpr,
-        NamedIR,
         aggregation as agg,
         boolean,
         functions as F,
@@ -32,21 +29,6 @@
     from narwhals.typing import IntoDType, PythonLiteral
 
 
-class ExprDispatch(StoresVersion, Protocol[FrameT_contra, R_co, NamespaceT_co]):
-    @classmethod
-    def from_ir(cls, node: ir.ExprIR, frame: FrameT_contra, name: str) -> R_co:
-        obj = cls.__new__(cls)
-        obj._version = frame.version
-        return node.dispatch(obj, frame, name)
-
-    @classmethod
-    def from_named_ir(cls, named_ir: NamedIR[ir.ExprIR], frame: FrameT_contra) -> R_co:
-        return cls.from_ir(named_ir.expr, frame, named_ir.name)
-
-    # NOTE: Needs to stay `covariant` and never be used as a parameter
-    def __narwhals_namespace__(self) -> NamespaceT_co: ...
-
-
 class CompliantExpr(StoresVersion, Protocol[FrameT_contra, SeriesT_co]):
     """Everything common to `Expr`/`Series` and `Scalar` literal values."""