I built a small trilogy of Go tools:

- fileprep — preprocessing & validation using struct tags (trim, replace, normalize, etc.)

- fileframe — a lightweight, immutable DataFrame for filtering, mapping, grouping

- filesql — run SQL directly on CSV/TSV/LTSV/Excel/Parquet (SQLite under the hood)

Repos:

- https://github.com/nao1215/fileprep

- https://github.com/nao1215/fileframe

- https://github.com/nao1215/filesql