status of rebindable syntax for arrows

[Simon Peyton Jones]

|  It already has a bug entry: #7828.  What would help is to know the
|  kind of use you have in mind, to see whether it fits with the proposed
|  solution.

Indeed.  Moreover #7828 is stalled; it needs some arrow-savvy person to focus cycles on it.  If rebindable syntax for arrows is considered important.

Meanwhile I think you should not rely on rebindable syntax for arrows. The user manual is misleading on this point.

Simon

|  -----Original Message-----
|  From: Glasgow-haskell-users [mailto:glasgow-haskell-users-
|  bounces at haskell.org] On Behalf Of Ross Paterson
|  Sent: 15 October 2014 06:56
|  To: glasgow-haskell-users
|  Subject: Re: status of rebindable syntax for arrows
|  
|  On Tue, Oct 14, 2014 at 10:26:46PM +0200, S. Doaitse Swierstra wrote:
|  > The GHC manual already for quite a number of version states:
|  >
|  > 	• Arrow notation (see Section 7.17, “Arrow notation ”) uses
|  whatever arr, (>>>), first, app, (|||) and loop functions are in
|  scope.
|  >          But unlike the other constructs, the types of these
|  functions must match the Prelude types very closely. Details are in
|  flux; if you want to use this, ask!
|  >
|  > When using this feature we get the error:
|  >
|  > "Var/Type length mismatch:
|  >    [s{tv aVL} [tv]]
|  >    []
|  > ghc: panic! (the 'impossible' happened)  (GHC version 7.8.3 for
|  > x86_64-apple-darwin):
|  > 	tcTyVarDetails s{tv aVL} [tv]
|  >
|  > Please report this as a GHC bug:
|  http://www.haskell.org/ghc/reportabug"
|  >
|  > So our question is whether we should really report this as a bug,
|  and/or what we can do about this.
|  
|  It already has a bug entry: #7828.  What would help is to know the
|  kind of use you have in mind, to see whether it fits with the proposed
|  solution.
|  _______________________________________________
|  Glasgow-haskell-users mailing list
|  Glasgow-haskell-users at haskell.org
|  http://www.haskell.org/mailman/listinfo/glasgow-haskell-users