Module extract_leaf_expressions 

Two-pass optimizer pipeline that pushes cheap expressions (like struct field access user['status']) closer to data sources, enabling early data reduction and source-level optimizations (e.g., Parquet column pruning). See ExtractLeafExpressions (pass 1) and PushDownLeafProjections (pass 2).

Structs

ExtractLeafExpressions

Extracts MoveTowardsLeafNodes sub-expressions from non-projection nodes into extraction projections (pass 1 of 2).

PushDownLeafProjections

Pushes extraction projections down through schema-preserving nodes towards leaf nodes (pass 2 of 2, after ExtractLeafExpressions).