~upd~ — Windowell Expressions

def _apply_frame(self, df: pd.DataFrame, window: WindowellExpression) -> pd.DataFrame: """Apply frame boundaries (simplified implementation)""" # Real implementation would handle ROWS BETWEEN X PRECEDING AND Y FOLLOWING frame = window.frame if frame.frame_type == "rows" and frame.start[1] == FrameBound.PRECEDING: # Rolling window logic return df.assign( _row_num=np.arange(len(df)), _window_start=lambda x: x._row_num - frame.start[0] ) return df class WindowellBuilder: """Fluent API for building window expressions"""

def evaluate(self, df: pd.DataFrame) -> int: return self.expression(df) dynamic_window = WindowellBuilder() .partition("category") .order("timestamp") .rows_between( DynamicBoundary(lambda df: df['lag'].max()), "preceding", 0, "current_row" ).build() 4. Testing Suite import unittest class TestWindowellExpressions(unittest.TestCase): windowell expressions

@dataclass class WindowellExpression: partition_by: List[str] order_by: List[str] frame: Optional[WindowFrame] = None name: Optional[str] = None def _apply_frame(self, df: pd

def partition(self, *columns): self.partition_by.extend(columns) return self window: WindowellExpression) -&gt