Simon, Richard, thank you for your answer! I don't have time to look into the GHC sources right now, but I will set aside some time after the holidays and take a close look at what the exact restrictions on proc-notation are and document them.
Since you suggested a rewrite of GHC's handling of proc-syntax, are there any opinions on integrating generalized arrows (Joseph 2014) in the process? I think they would greatly improve arrows! I don't know if I have the time to attempt this, but if I find the time I would give it a try. Why wasn't this integrated while it was still actively developed? Best, Jan [Joseph 2014] https://www2.eecs.berkeley.edu/Pubs/TechRpts/ 2014/EECS-2014-130.pdf 2016-11-29 12:41 GMT+00:00 Simon Peyton Jones <simo...@microsoft.com>: > Jan, > > > > Type checking and desugaring for arrow syntax has received Absolutely No > Love for several years. I do not understand how it works very well, and I > would not be at all surprised if it is broken in corner cases. > > > > It really needs someone to look at it carefully, document it better, and > perhaps refactor it – esp by using a different data type rather than > piggy-backing on HsExpr. > > > > In the light of that understanding, I think rebindable syntax will be > easier. > > > > I don’t know if you are up for that, but it’s a rather un-tended part of > GHC. > > > > Thanks > > > > Simon > > > > *From:* ghc-devs [mailto:ghc-devs-boun...@haskell.org] *On Behalf Of *Richard > Eisenberg > *Sent:* 28 November 2016 22:30 > *To:* Jan Bracker <jan.brac...@googlemail.com> > *Cc:* ghc-devs@haskell.org > *Subject:* Help needed: Restrictions of proc-notation with > RebindableSyntax > > > > Jan’s question is a good one, but I don’t know enough about procs to be > able to answer. I do know that the answer can be found by looking for uses > of `tcSyntaxOp` in the TcArrows module.... but I just can’t translate it > all to source Haskell, having roughly 0 understanding of this end of the > language. > > > > Can anyone else help Jan here? > > > > Richard > > > > On Nov 23, 2016, at 4:34 AM, Jan Bracker via ghc-devs < > ghc-devs@haskell.org> wrote: > > > > Hello, > > > > I want to use the proc-notation together with RebindableSyntax. So far > what I am trying to do is working fine, but I would like to know what the > exact restrictions on the supplied functions are. I am introducing > additional indices and constraints on the operations. The documentation [1] > says the details are in flux and that I should ask directly. > > > > Best, > > Jan > > > > [1] https://downloads.haskell.org/~ghc/latest/docs/html/ > users_guide/glasgow_exts.html#rebindable-syntax-and-the- > implicit-prelude-import > <https://na01.safelinks.protection.outlook.com/?url=https:%2F%2Fdownloads.haskell.org%2F~ghc%2Flatest%2Fdocs%2Fhtml%2Fusers_guide%2Fglasgow_exts.html%23rebindable-syntax-and-the-implicit-prelude-import&data=02%7C01%7Csimonpj%40microsoft.com%7C80e472cedf78463bd18408d417de1af5%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636159690104764444&sdata=ygqePSmgcPKnPmKDBfZplkyjG9BIDBO1L1MWHNpqw88%3D&reserved=0> > > _______________________________________________ > ghc-devs mailing list > ghc-devs@haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs > > >
_______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs