2022-04-04.md

SWG 2022-04-04

Meeting URL: https://meet.jit.si/StableHaskellMeetBiWeekly

Previous meeting notes

Agenda

• GHC.X.Hackage update
• Update on GHC tick-tock releases
• Update on Language/compiler features to help stability
• Update on API breakage policy
• Type variable binders in datatypes and Discourse discussion
• Proposed Data.List monomorphisation

Notes

• GHC.X.Hackage update

  • Ben: Met with Andrea Bedini, the maintainer of foliage to guide technical direction. "Foliage is a tool to create custom or private Haskell package repositories, in a fully reproducible way."
  • Looks to be a good foundation for the proposed extensions to head.hackage
  • Currently still struggling to find time to engage in discussion
  • Parked until GHC 9.4 is branched
  • Holding the token: Ben

• Update on GHC tick-tock releases

  • Similarly, struggling to find time to push forward discussion
  • Parked until GHC 9.4 is branched
  • Holding the token: Ben

• Update on Language/compiler features to help stability

  • Main idea: collect ideas for language suppport that would help to mitigate the cost of change, and

    • refine,
    • categorise,
    • prioritise

  • Then present them to the Haskell community, inviting

    • feedback
    • further ideas
    • actual cycles to help develop them

  • Then turn (some of) them into proper GHC proposals

  • Notes from Ben and Trevis's discussion

  • One refinement already

  • For now, Trevis is holding the token.

• Update on API breakage policy

  • TE published Opaleye's API breakage policy
  • TE submitted to Reddit, Discourse and asked for example of other policies but not much came back.
  • Main payload for now: opt-in advice for library authors.
  • 3 release policy was also mentioned here
    • https://gitlab.haskell.org/haskell/prime/-/wikis/libraries/3-release-policy

• Type variable binders in datatypes and Discourse

  • Discussion was great, we want more
    • The more it happens we hope the involvement will increase

• Proposed Data.List monomorphisation

  • Want to make sure those who would dislike it are being heard

Reducing the pain of breakage

• Making fewer changes (more conservatism)
  • Just don't changes things at all
• Making changes that break less:
  • Introducing language and compiler changes to make compatibility easier to achieve in the face of interface changes
• Breaking with more support:
  • Automated migration and refactoring tools
    • 2to3 (Python)
    • scalafix https://scalacenter.github.io/scalafix/
    • cargo fix https://doc.rust-lang.org/cargo/commands/cargo-fix.html
    • rerast
    • Jetbrains does this in editor for some languages eg https://www.jetbrains.com/help/ruby/refactoring-source-code.html#ecca098