**Session Date/Time:** 01 Apr 2026 14:00

# [CBOR](../wg/cbor.html)

## Summary
The session focused on the progression of Extended Diagnostic Notation (EDN) documents, specifically [draft-ietf-cbor-edn-literals](https://datatracker.ietf.org/doc/draft-ietf-cbor-edn-literals/). Carsten Bormann provided a status update on the transition of EDN from an update of existing RFCs to a standalone specification with normative ABNF. The group discussed recent technical changes including raw strings and debated the expansion of comment syntax to improve usability and compatibility with JSON-based tools. A timeline was established for a second Working Group Last Call (WGLC) in April 2025.

## Key Discussion Points

### Status of EDN Literals
Carsten Bormann presented the history and current status of [draft-ietf-cbor-edn-literals](https://datatracker.ietf.org/doc/draft-ietf-cbor-edn-literals/).
* **Restructuring:** Following IESG feedback, the document was changed from an "update" to RFC 8949 and RFC 8610 into a standalone document incorporating all EDN definitions.
* **Objectives:** EDN is intended for diagnostics, test vectors, configuration files, and documentation (specifically fitting within 69-column constraints).
* **Recent Changes:** Version -21 includes ABNF for integrated parsers using raw strings for hex and base64 byte strings.

### Raw Strings and Usability
* Carsten Bormann highlighted the addition of raw strings (using backquotes) to avoid "quoting hell" and backslash-processing overhead. 
* The implementation allows for any number of backquotes as delimiters to wrap strings containing backquotes.

### Comment Syntax (Issue 82 / PR 83)
A significant portion of the meeting was dedicated to proposed changes to comment syntax in [draft-ietf-cbor-edn-literals](https://datatracker.ietf.org/doc/draft-ietf-cbor-edn-literals/).
* **Current state:** Inline comments use slashes `/ comment /` and end-of-line (EOL) comments use the hash `#`.
* **Proposed EOL comments:** There is interest in adding `//` as an EOL comment delimiter to align with common JSON extensions (JSONC, JSON5). Carsten Bormann noted this creates a minor non-backwards compatible change where empty inline comments `//` would no longer be valid.
* **Proposed Inline comments:** Discussion regarding adding C-style `/* ... */` comments.
    * Christian Amsüss argued for an asterisk-based form to allow URLs (which contain slashes) to be included in comments without breaking syntax.
    * Carsten Bormann observed that while he personally finds the asterisk syntax less than ideal, it facilitates copy-pasting from other text formats like JSONC/JSON5.
    * Вадим Гончаров and Carsten Bormann discussed historical precedents (Pascal, PL/I) for such delimiters.
* **Sense of the Room:** There was general sympathy among participants for including `/* ... */` and `//` style comments to improve developer experience, despite minor compatibility impacts.

### EDN Extensions
The group discussed [draft-ietf-cbor-edn-e-ref](https://datatracker.ietf.org/doc/draft-ietf-cbor-edn-e-ref/) and future extension possibilities.
* **Current Extensions:** The "E" and "REF" extensions are already being used.
* **Future Ideas:** Carsten Bormann mentioned potential extensions for `FLOAT` (non-finite values), `BOTH` (providing both raw and semantic representations for verification), and Base32 conversions.
* **Strategy:** Ira McDonald suggested avoiding a proliferation of small documents. Christian Amsüss suggested batched updates similar to how CDDL extensions have been handled in the past.

## Decisions and Action Items
* **Decision:** The working group will move forward with adding `//` (EOL) and `/* ... */` (inline) comment syntax to [draft-ietf-cbor-edn-literals](https://datatracker.ietf.org/doc/draft-ietf-cbor-edn-literals/).
* **Action Item:** Carsten Bormann to update the draft and associated implementation tools with the agreed-upon comment syntax.
* **Action Item:** All participants are encouraged to review their existing EDN collections to verify if the non-backwards compatible change regarding `//` impacts their use cases.

## Next Steps
* **Timeline:** 
    * Merge existing Pull Requests and close relevant issues by the end of March 2025.
    * Initiate a second Working Group Last Call for [draft-ietf-cbor-edn-literals](https://datatracker.ietf.org/doc/draft-ietf-cbor-edn-literals/) in April 2025.
    * Aim for IESG submission by May or June 2025.
* **Mailing List:** Christian Amsüss will take the detailed overview of string types to the mailing list for further discussion.

***

**Reference Materials:**
* Slide Deck: [EDN](https://datatracker.ietf.org/meeting/interim-2026-cbor-06/materials/slides-interim-2026-cbor-06-sessa-edn-01)