Hi everyone, here are the minutes of the meeting: --- # Cabal meeting (17/08/2023)
Previously: https://hackmd.io/2EPSwwg8QqqZ96cFdW2wTQ ## Next Release - Help needed with [#9088](https://github.com/haskell/cabal/pull/9088). - Hécate: If we can't get it through, we'll skip it for this backport. ## Cabal exact-printing in HLS * HLS has a cabal plugin: https://discourse.haskell.org/t/hsoc-hls-cabal-file-support/7331/2 * Establishing a context for completions (Value Context, Keyword Context, ...) is not easily possible * Custom parsing that works 95% of the time is used. * Fitting .cabal intermediate structures would improve the code and reduce maintenance burden for HLS team. * Often requested feature in HLS: https://github.com/haskell/haskell-language-server/issues/3595 * Requires parsing and modifying .cabal files without modifying the rest of the cabal file * GenericPackageDescription insufficient due to loss of Source Positions * Intermediate representations of .cabal files are unknown / hard to discover * Custom megaparsec parser used for POC of Code Action "Add module to exposed-modules" field. * FYI, this code action is working for a lot of use-cases already * Explicit goal of being an exactprinter * See [megaissue]( https://github.com/haskell/cabal/issues/7544#issuecomment-934009792) (and there is a whole github project, linked to in the issue). * While the HLS's custom parser serves a different purpose, it'd be much nicer if we could re-use Cabal directly * In a dicussion, @fendor and @andreabedini talked about a way forward: * Let's make `[Field ann]` roundtripping by modifying the lexer * Trailing whitespace needs to be handled * Comments need to be handled * Are braces currently handled in the lexer or are they a part of `ann`? * POC branch by @andreabedini available * `Field ann` gives us enough information to implement the Code Action for HLS * Ideally, we also make `Fields ann` (note: different intermediate representation) roundtrip with `[Field ann]` Pros: * We are relatively close to achieving roundtrips of `[Field ann] <-> .cabal` * Immense help for tooling already Cons: * No field analysis, further parsing required. Proposed roadmap: 1. HLS releases with the Code Action using a custom parser 2. The custom parser is replaced by `[Field ann]` internally, but still permitting an interface HLS can use 3. Improve the lexer and enable roundtripping of `[Field ann] <-> .cabal file` 4. Evaluate what Code Actions and IDE features can be implemented on top of that ## Cabal nix integration - [Users’ survey]( https://discourse.haskell.org/t/community-survey-removing-cabals-nix-integration/7201/12 ). - tl;dr: most people do not use it, with some exceptions (see message by neil.mayhew). - Some use *stack* nix integration, but I am not sure it is actually the same thing as `cabal`. (I am told it is by various `stack` users. *++bsa*) *Action Item: We kill it.* ## Other topics - GHC 9.8 Hécate: 3.10.2.0 release will also be shipped with GHC 9.8. It needs to be patched in order to recognise it as a legal version. On Sat, 12 Aug 2023 at 15:53, Theophile Hécate Choutri <hecate@haskell.foundation> wrote: > Hi everyone, > You'll find below the link to the agenda and minutes: > > https://hackmd.io/78RP9BOAQFiq_GM1qNRpYQ?both > > Please do take the time to add the topics you want to raise. We already > have a discussion about the exact-print parser that is being developed for > HLS, and this would be an appropriate moment to determine our current > legacy in terms of parsers within the code base. > > See you next week, > Hécate >
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