#11149: Unify fixity/associativity of <>-ish pretty-printing operators -------------------------------------+------------------------------------- Reporter: hvr | Owner: Type: task | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by hvr: Old description:
This ticket is motivated by GHC's new `-fwarn-semigroup`, and that `<>` is moving into `Prelude` with future GHCs.
Throughout GHC's source there are related pretty-printing operators with subtly different `infixr/infixl`-declarations.
It would be desirable to unify those and possibly use `Semigroup((<>))` instead (where `<>` represents a semigroup/monoid operation anyway)
Otoh, existing code using `<>` assumes a different fixity (Monoid/Semigroup have `infixr 6 <>`), so it may make sense to start by renaming the unconventional `<>`s into something else.
Modules affected:
- `Outputable`: default fixity, i.e. `infixl 9` (ghc) - `Pretty`: `infixl 6` (ghc) - `Language.Haskell.TH.PprLib`: `infixl 6` (template-haskell)
Related discussion: https://github.com/haskell/pretty/issues/30
New description: {{{#!box note See also Proposal/LeftAssocSemigroupOp }}} This ticket is motivated by GHC's new `-fwarn-semigroup`, and that `<>` is moving into `Prelude` with future GHCs. Throughout GHC's source there are related pretty-printing operators with subtly different `infixr/infixl`-declarations. It would be desirable to unify those and possibly use `Semigroup((<>))` instead (where `<>` represents a semigroup/monoid operation anyway) Otoh, existing code using `<>` assumes a different fixity (Monoid/Semigroup have `infixr 6 <>`), so it may make sense to start by renaming the unconventional `<>`s into something else. Modules affected: - `Outputable`: default fixity, i.e. `infixl 9` (ghc) - `Pretty`: `infixl 6` (ghc) - `Language.Haskell.TH.PprLib`: `infixl 6` (template-haskell) Related discussion: https://github.com/haskell/pretty/issues/30 -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11149#comment:5 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler