ddn.df.io

Dataframe IO for D: CSV and Arrow IPC read, scan and write over ddn-df.

This package is the integration layer of the DDN Analytics family: it connects the file formats to eager frames, lazy sources and incremental sinks. It owns readCsv, writeCsv, scanCsv, readIpcFile, scanIpc and the incremental dataframe sinks - schema inference, CSV-to-column conversion and the dataframe CSV rendering path - implemented over the generic ddn.data.csv scanner of DDN core and the Arrow codecs of ddn-data-arrow.

It is deliberately not another codec library: type mappings, FlatBuffers framing and compression belong to the Arrow package, and the generic lexical parser belongs to DDN core. This layer owns source lifecycle - projection and error rules, early stop, rewindable versus single-use sources, Windows handle closure and atomic temporary-file publication - and the private DDNDF1 legacy format under an honest module name that never advertises it as Arrow IPC.

The delivered surface covers eager CSV/Arrow IPC reads and writes, lazy scans and incremental sinks, plus the all-format integration suites and foreign round-trip fixtures owned by the IO layer.