- ghc-steering-committee

Please review #368: Warn on prefix/suffix operators, Shepherd: Tom
by Joachim Breitner 02 Feb '21

02 Feb '21

Dear Committee, this is your secretary speaking: Warn on prefix/suffix operators has been proposed by Richard https://github.com/ghc-proposals/ghc-proposals/pull/368 This is an amendment to #229 (Whitespace-sensitive operator parsing), see the PR description linked above for details. I’ll propose Tom as the shepherd. Please guide us to a conclusion as outlined in https://github.com/ghc-proposals/ghc-proposals#committee-process Thanks, Joachim -- Joachim Breitner mail(a)joachim-breitner.de http://www.joachim-breitner.de/

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Steering Committee bylaws
by Richard Eisenberg 22 Jan '21

22 Jan '21

Hi all, Some time ago, I posted https://github.com/ghc-proposals/ghc-proposals/pull/360 <https://github.com/ghc-proposals/ghc-proposals/pull/360>, an attempt at crafting bylaws for this committee. Conversation has died down, and so I'd like to have a discussion that will lead to amendments and then eventual acceptance (of something). I think it's best for this discussion to be right on the PR, not this thread. However, given that this PR is all about how we function, as a committee, I would like to see participation (ideally, agreement!) from everyone here before proceeding, even if it's just a LGTM. Thanks! Richard

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Please review #387: The Char kind, Shepherd: Alejandro
by Joachim Breitner 22 Jan '21

22 Jan '21

Dear Committee, this is your secretary speaking: The Char Kind has been proposed by Daniel Rogozin https://github.com/ghc-proposals/ghc-proposals/pull/387 https://github.com/serokell/ghc-proposals/blob/master/proposals/0000-char-k… I’ll propose Alejandro as the shepherd. Please guide us to a conclusion as outlined in https://github.com/ghc-proposals/ghc-proposals#committee-process Thanks, Joachim -- Joachim Breitner mail(a)joachim-breitner.de http://www.joachim-breitner.de/

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#380 GHC2021: Voting starts
by Joachim Breitner 18 Jan '21

18 Jan '21

Dear Committee, the requested data (hackage and survey) is in, has been aggregated, cooked, seasoned and is ready for consumption. 116 extensions are waiting on your assessment, so time to vote! ## Procedure Please vote by email to this list, in a response to this thread. I want to make tallying easy and automatic, and my code will consider an extension Foo voted for if you write "Foo: yes" on its own line. This means you can include rationales, write "Foo: maybe" and "Foo: no" to remind yourself and others that about where you are, and you can safely quote other’s mails. For example, if you write: ---- begin example ---- Easy ones: DeriveFooBar: yes OverloadedBen: no These ones are tricky: ImplicitExceptions: yes I know nobody likes that one, but I do. RandomEvaluationOrder: maybe Not sure about this one, here is why… > Richard wrote: > DependentHaskell: yes > Rationale: See my thesis I’m not convinced yet, tell me more, so DependentHaskell: maybe ---- end example ---- then you have voted for DeriveFooBar and ImplicitExceptions. Only “yes” matters, “no”, “maybe” and “later” are all ignored. I will shortly send my first ballot around. Also see the end of this mail for a copy’n’paste template. You can update your vote as often as you want. Please always send your full votes (I will only consider your latest email). I encourage you to do that early, e.g. maybe start with a mail where you list the obvious yes and nos, and keep some at maybe and then refine. The timeline says first votes should be in within two weeks, and then a bit more to refine. But the earlier the merrier! The quota is 8. In particular, if everyone votes (and I hope everyone will), an extension won’t make it this round if 4 don’t include it. ## Data Please see https://github.com/ghc-proposals/ghc-proposals/blob/ghc2021/proposals/0000-… for the data, including explanations. It is intentionally not sorted by the data, as the choice of ranking function would already be quite influencing. You may want to play around with that data, e.g. sort it by your own criteria etc. I looked long for an online service where I can upload the data and allow you to explore it, but then I noticed that that's a bit stupid, since we all probably can do it best with Haskell. So I made it easy to load the data into GHCi, see the instructions at https://github.com/nomeata/ghc-proposals-stats/blob/master/ext-stats/README… which allow you, for example, to do this *Main> mapM_ (\E{..} -> Text.Printf.printf "%s: %d\n" ext survey_no) $ take 10 $ reverse $ sortOn (\E{..} -> survey_no) (M.elems exts) AllowAmbiguousTypes: 195 CPP: 192 IncoherentInstances: 176 Arrows: 156 Strict: 153 ImplicitParams: 147 UndecidableInstances: 144 OverlappingInstances: 144 Unsafe: 139 TemplateHaskell: 137 Of course, if someone wants to upload the data somewhere and share that, that's also useful. Let me know if some of this doesn't quite work for you, and should be improved. Maybe we need a web form instead of mails? ## PS: Blank ballot To start, you could copy the following into an email AllowAmbiguousTypes: maybe ApplicativeDo: maybe Arrows: maybe BangPatterns: maybe BinaryLiterals: maybe BlockArguments: maybe CApiFFI: maybe CPP: maybe CUSKs: maybe ConstrainedClassMethods: maybe ConstraintKinds: maybe DataKinds: maybe DatatypeContexts: maybe DefaultSignatures: maybe DeriveAnyClass: maybe DeriveDataTypeable: maybe DeriveFoldable: maybe DeriveFunctor: maybe DeriveGeneric: maybe DeriveLift: maybe DeriveTraversable: maybe DerivingStrategies: maybe DerivingVia: maybe DisambiguateRecordFields: maybe DuplicateRecordFields: maybe EmptyCase: maybe EmptyDataDecls: maybe EmptyDataDeriving: maybe ExistentialQuantification: maybe ExplicitForAll: maybe ExplicitNamespaces: maybe ExtendedDefaultRules: maybe FlexibleContexts: maybe FlexibleInstances: maybe ForeignFunctionInterface: maybe FunctionalDependencies: maybe GADTSyntax: maybe GADTs: maybe GHCForeignImportPrim: maybe GeneralisedNewtypeDeriving: maybe HexFloatLiterals: maybe ImplicitParams: maybe ImportQualifiedPost: maybe ImpredicativeTypes: maybe IncoherentInstances: maybe InstanceSigs: maybe InterruptibleFFI: maybe KindSignatures: maybe LambdaCase: maybe LexicalNegation: maybe LiberalTypeSynonyms: maybe LinearTypes: maybe MagicHash: maybe MonadComprehensions: maybe MonadFailDesugaring: maybe MonoLocalBinds: maybe MultiParamTypeClasses: maybe MultiWayIf: maybe NPlusKPatterns: maybe NamedFieldPuns: maybe NamedWildCards: maybe NegativeLiterals: maybe NoImplicitPrelude: maybe NoMonomorphismRestriction: maybe NoPatternGuards: maybe NoTraditionalRecordSyntax: maybe NondecreasingIndentation: maybe NullaryTypeClasses: maybe NumDecimals: maybe NumericUnderscores: maybe OverlappingInstances: maybe OverloadedLabels: maybe OverloadedLists: maybe OverloadedStrings: maybe PackageImports: maybe ParallelListComp: maybe PartialTypeSignatures: maybe PatternSynonyms: maybe PolyKinds: maybe PostfixOperators: maybe QualifiedDo: maybe QuantifiedConstraints: maybe QuasiQuotes: maybe RankNTypes: maybe RebindableSyntax: maybe RecordWildCards: maybe RecursiveDo: maybe RoleAnnotations: maybe Safe: maybe ScopedTypeVariables: maybe StandaloneDeriving: maybe StandaloneKindSignatures: maybe StarIsType: maybe StaticPointers: maybe Strict: maybe StrictData: maybe TemplateHaskell: maybe TemplateHaskellQuotes: maybe TransformListComp: maybe Trustworthy: maybe TupleSections: maybe TypeApplications: maybe TypeFamilies: maybe TypeFamilyDependencies: maybe TypeInType: maybe TypeOperators: maybe TypeSynonymInstances: maybe UnboxedSums: maybe UnboxedTuples: maybe UndecidableInstances: maybe UndecidableSuperClasses: maybe UnicodeSyntax: maybe UnliftedFFITypes: maybe UnliftedNewtypes: maybe Unsafe: maybe ViewPatterns: maybe -- Joachim Breitner mail(a)joachim-breitner.de http://www.joachim-breitner.de/

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Please review #313: Delimited continuation primops, Shepherd: Simon Marlow
by Joachim Breitner 18 Jan '21

18 Jan '21

Dear Committee, this is your secretary speaking: Delimited continuation primops has been proposed by Alexis King https://github.com/ghc-proposals/ghc-proposals/pull/313 https://github.com/lexi-lambda/ghc-proposals/blob/delimited-continuation-pr… I’ll propose Simon Marlow as the shepherd. Please guide us to a conclusion as outlined in https://github.com/ghc-proposals/ghc-proposals#committee-process Thanks, Joachim -- Joachim Breitner mail(a)joachim-breitner.de http://www.joachim-breitner.de/

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Status
by Joachim Breitner 18 Jan '21

18 Jan '21

Dear Committee, after 2½ months, time for a new status updates. What was going on here? * Well, GHC2021 was going on. Lots of it. But it’s actually coming to a close in five days. It will be exciting to see how it affects the Haskell landscapes. * Heh, last status I wrote: Richard refines the bylaws in #360. Maybe everybody has a second look now and then we can merge this? I guess that still applies. Richard and I are discussing a corner case on the PR, but otherwise approvals are coming in, and unless that changes, we’ll merge that once we ironed out that wrinkle. * Simon introduced the position of a nudger, namely Tom. Tom, below are some PRs where you might need to nudge someone! * we were asked to review these proposals: #366: DuplicateRecordFields without ambiguous field access, shepherd: Tom #242: Unsaturated type families, Shepherd: Richard Eisenberg #370: Syntax for Modifiers, Shepherd: Alejandro #387: The Char kind, Shepherd: Alejandro #368: Warn on prefix/suffix operators, Shepherd: Tom #381: Visible 'forall' in types of terms, Shepherd: Iavor * we have a recommendation from the shepherd about: #369: Add sumToTag# primop, (rec: accept) #366: DuplicateRecordFields without ambiguous field access (rec: accept) #381: Visible 'forall' in types of terms (rec: reject) #242: Unsaturated type families (rec: accept) #313: Delimited continuation primops (rec: accept) #370: Syntax for Modifiers (rec: accept) #387: The Char kind (rec: accept) * we have sent the following proposals back to revision #283: Local modules * we decided about the following proposals #366: DuplicateRecordFields without ambiguous field access (accept) #370: Syntax for Modifiers (accept) #242: Unsaturated type families (accept) In addition to the two meta-proposals (bylaws and GHC2021), we currently have to act on the following 7 proposals, up by 2! Some need some nudging. ## Waiting for committee decision #387: The Char kind, Shepherd: Alejandro Looks like it’ll be smoothly accepted, but it’s only a week old. Will maybe merge in a few days. #381: Visible 'forall' in types of terms, Shepherd: Iavor Recommendation was to reject, but discussion went into the more abstract “whither dependent Haskell”. But what does this mean for this proposal? #369: Add sumToTag# primop Essentially accepted, waiting for feedback from the author on final tweaks #313: Delimited continuation primops, Shepherd: Simon Marlow Mostly positive reception, but there was discussion. Simon, can this be accepted as it, or does it need more work/time/discussion? #302: \of, Shepherd: Cale No new discussion. Cale, what is the conclusion? ## Waiting for Shepherd action #367: Clarify primops using unboxed sums, Shepherd: Simon Marlow This is aging… we need a shepherd recommendation #368: Warn on prefix/suffix operators, Shepherd: Tom Tom, your turn Cheers, Joachim -- Joachim Breitner mail(a)joachim-breitner.de http://www.joachim-breitner.de/

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GHC2021 extensions should be sufficient for early intermediate Haskellers
by Richard Eisenberg 21 Dec '20

21 Dec '20

Hi all, In thinking about how I feel about TypeFamilies (and why I lean against inclusion), I realized I had a new criterion: * GHC2021 extensions should be sufficient for early-intermediate Haskellers Today, users have to enable a number of extensions just to get basic work done (I'm looking at you, FlexibleContexts). So they learn just to take whatever suggestion is presented to them in an error message and apply it. But if extensions were considered more exotic, then users might not be so willing to add an extension. They would have to consider whether they really want to opt into more challenging error messages and a wider horizon. TypeFamilies is an extension that significantly widens the horizon, but also invites new scary error messages. I think it should be opt in. But this gatekeeping works only if users will be thoughtful about enabling the extension; thus my new criterion. What do we think about this? (I thought of putting this on Kialo, but it didn't seem to fit the setup there. Maybe I've erred in not just blasting ahead.) Richard

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Please review #370: Syntax for Modifiers, Shepherd: Alejandro
by Joachim Breitner 18 Dec '20

18 Dec '20

Dear Committee, this is your secretary speaking: A syntax for modifiers has been proposed by Richard Eisenberg (this time it’s true) https://github.com/ghc-proposals/ghc-proposals/pull/370 https://dfinity.slack.com/archives/C01BJ73A893/p1605922403340800?thread_ts=… I’ll propose Alejandro as the shepherd, as he has looked at i t in detail already. Please guide us to a conclusion as outlined in https://github.com/ghc-proposals/ghc-proposals#committee-process Thanks, Joachim -- Joachim Breitner mail(a)joachim-breitner.de http://www.joachim-breitner.de/

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A few more pleas
by Richard Eisenberg 10 Dec '20

10 Dec '20

A plea for DerivingStrategies: GHC currently chooses which strategy to use rather arbitrarily. (For example, did you know that Eq and Ord are derived by GeneralizedNewtypeDeriving whenever possible, even when that extension isn't enabled?) And Show is always derived by the `stock` strategy, even when GND is enabled (and otherwise possible). Instead, DerivingStrategies allows users to be explicit, and (in my opinion) should be a matter of good style, just like top-level type signatures. Having to enable the extension to use good style is an annoying hurdle. While the set of strategies may evolve, the idea of writing out strategies (and their syntax) feels stable to me. A plea for NamedWildCards: This feature allows type variables beginning with an underscore to be treated as a component in a partial type signature. Critically (for this plea), a type signature with a named wild card will not be accepted without -XPartialTypeSignatures. I do *not* advocate for -XPartialTypeSignatures! So, having -XNamedWildCards on simply means that we get an informative error message when the user writes a type variable beginning with an underscore. The only downside is that programs such as id :: _a -> _a are no longer accepted. But does anyone write type variables with leading underscores? If we think this is at all common, then I would change my mind here. Why have it on by default? Because it's not easily discoverable, and the error messages really are quite nice. A plea against MonoLocalBinds (and, hence, TypeFamilies): MonoLocalBinds is fork-like: it will mean that some Haskell98 programs will not be accepted. And to get those programs accepted, a user might need ScopedTypeVariables -- in specific, the aspect of ScopedTypeVariables that seems likeliest to change in the future. So I don't think we should have MonoLocalBinds on by default. Thanks for reading! Richard

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A plea against "fancy types" in GHC2021
by Iavor Diatchki 09 Dec '20

09 Dec '20

Hello, I would like to advocate that things like `DataKinds`, `TypeFamilies`, and `GADTs` are not enabled by default in GHC2021. The reason I ask for this is that unlike many others, I think these extensions convey useful information about the mindset you should use when working with a specific code base, which is quite different from working with ordinary Haskell. I do think it would be quite reasonable to have an umbrella extensions for FancyTypes too, which would enable all of those, I just don't think they should be enabled for every Haskell program. -Iavor

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