August SIP Meeting Results: 2 SIPs Rejected and 2 SIPs Updated

Monday 15 August 2016

Jorge Vicente Cantero


On August 10, the Scala Improvement Process (SIP) Committee held their monthly meeting to discuss and give feedback on four proposals, both new and old. We’re happy that these discussions sparked so much interest and participation in the community. It’s comforting to see the new SIP process becoming fruitful!

Of the four discussed proposals, two were unanimously rejected. The other two progressed and will have a follow-up iteration.

The rejected proposals were:

  • SIP-12: Uncluttering Scala’s syntax for control structures. Originally proposed in 2011. The proposal suggested syntax changes in if’s, for and while loops, moving Scala’s syntax away from Java and C-like languages. Whereas such changes may be arguably more beautiful, the Committee agreed that would give more problems than benefits. Seth Tisue, the appointed reviewer, fully explains the Committee’s reaction here.
  • SIP-16: Self-cleaning macros. Originally proposed in 2012. Macros add a whole new dimension to the Scala language. Their experimental implementation was adopted by a lot of Scala libraries and were immensely useful for the creation and evolution of first-class Scala tools. As described by his creator and reviewer, Eugene Burmako, they turned out to be a good experiment, but one that could be improved if major downsides in the design were addressed. With the intention of letting scala.meta eventually replace the old macros, he proposed rejecting SIP-16 to revisit its basic foundations and create a new proposal that would considerably enhance the metaprogramming experience in Scala. In the meantime, the experimental implementation will remain in place. If you’re interested in Eugene’s explanation, follow this.

The two proposals that made it to the next iteration are SIP-23: Literal-based singleton types (reviewer: Adriaan Moors) and SIP-27: Trailing Commas (reviewer: Eugene Burmako). The reviewers and committee members provided more feedback to iterate on. Both proposals already have provisional implementations and will continue to be discussed for inclusion in the language.

Overall, we’re happy to report these results and see Scala continue to move forward! We’re excited to see the Scala community speaking up and collaborating with the process—your vibrant responses will greatly enrich our future deliberations.

Next month, we’ll discuss five more proposals, including SIP-21: Spores and SIP-24: Repeated by-name parameters. We hope to finish off the list of old proposals in the queue and focus ourselves on the most recent proposals and the ones that are to come!

Did you know that each month, we conduct these SIP meetings on-air? You can tune in and ask questions to the SIP committee, and have them answered live. Videos of the meetings are then archived on YouTube. Check the minutes of this meeting in the SIP website.