Go 1.23 iter Package Powers Unified Streaming Interface in RagPack Library

A developer building RagPack, an open-source Go library that chunks files for vector embedding, needed a single contract to stream parsed content across multiple file formats including CSV, PDF, DOCX, HTML, and Markdown. Rather than implementing separate iterator patterns per format, they leveraged the iter package introduced in Go 1.23, which provides the Seq and Seq2 generic function types for yielding values lazily. The iter.Seq2[Unit, error] type was chosen as the return type for a shared Parser interface, aligning naturally with Go's conventional value-error pair pattern and allowing inline error handling without extra struct wrappers. Each format-specific parser implements the same single Parse method, meaning the ingester loop remains unchanged regardless of which parser is supplied. For streaming formats, the approach also keeps memory usage constant regardless of file size, since content is yielded one unit at a time rather than loaded all at once.