#7828: RebindableSyntax and Arrow -------------------------------------+------------------------------------- Reporter: | Owner: jstolarek AlessandroVermeulen | Status: new Type: bug | Milestone: 7.10.1 Priority: normal | Version: 7.6.2 Component: Compiler | Keywords: (Type checker) | Architecture: Unknown/Multiple Resolution: | Difficulty: Unknown Operating System: | Blocked By: Unknown/Multiple | Related Tickets: #1537, #3613 Type of failure: GHC | rejects valid program | Test Case: | Blocking: | Differential Revisions: Phab:D72 | -------------------------------------+------------------------------------- Comment (by simonpj): I'm sorry Jan I'm struggling with this one. My main difficulty is that I don't understand arrows well enough, and I do not have a stand-alone document giving the typing rules they are supposed to obey, one that matches the syntax and deguaring used in GHC. (There are some changes described above, and I do not know how they fit in either.) What would be really helpful would be a wiki page or Latex document that gave * The syntax for arrows, including a clear indication of how it is represented in !HsSyn * The static semantics as typing rules * The desugaring into Core The second and third of these are connected, because the type checker must generate the evidence that will be used by the desugarer to translate to Core. I believe that the static semantics may be specified (perhaps only in part), as comment:17 suggests, by translation into some simpler combinators. In short, it's a nice, cleanly-separable problem; and has clear intellectual challenge; but I feel unable to contribute much at the moment. Simon -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/7828#comment:46 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler