some new features

.venv/lib/python3.12/site-packages/narwhals/_sql/dataframe.py

@@ -0,0 +1,30 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any, Protocol
+
+from narwhals._compliant.dataframe import CompliantLazyFrame
+from narwhals._compliant.typing import CompliantExprT_contra, NativeExprT, NativeFrameT
+from narwhals._translate import ToNarwhalsT_co
+
+if TYPE_CHECKING:
+    from typing_extensions import Self, TypeAlias
+
+    from narwhals._compliant.window import WindowInputs
+    from narwhals._sql.expr import SQLExpr
+
+    Incomplete: TypeAlias = Any
+
+
+class SQLLazyFrame(
+    CompliantLazyFrame[CompliantExprT_contra, NativeFrameT, ToNarwhalsT_co],
+    Protocol[CompliantExprT_contra, NativeFrameT, ToNarwhalsT_co],
+):
+    def _evaluate_window_expr(
+        self,
+        expr: SQLExpr[Self, NativeExprT],
+        /,
+        window_inputs: WindowInputs[NativeExprT],
+    ) -> NativeExprT:
+        result = expr.window_function(self, window_inputs)
+        assert len(result) == 1  # debug assertion  # noqa: S101
+        return result[0]