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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?<o:p></o:p></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">The arrow stuff was added to GHC years before this thesis (which I had not seen before – thanks). I don’t have an opinions about<o:p></o:p></span></p>
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</span></span></span><![endif]><span style="font-family:"Calibri",sans-serif">the desirability<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-family:Symbol"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="font-family:"Calibri",sans-serif">the difficulty<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">of integrating generalised arrows.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">You’re in the driving seat! By all means give it a go.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif">Simon<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Jan Bracker [mailto:jan.bracker@googlemail.com]
<br>
<b>Sent:</b> 02 December 2016 15:58<br>
<b>To:</b> Simon Peyton Jones <simonpj@microsoft.com><br>
<b>Cc:</b> Richard Eisenberg <rae@cs.brynmawr.edu>; ghc-devs@haskell.org; Ross Paterson (ross@soi.city.ac.uk) <ross@soi.city.ac.uk>; Henrik Nilsson <Henrik.Nilsson@nottingham.ac.uk><br>
<b>Subject:</b> Re: Help needed: Restrictions of proc-notation with RebindableSyntax<o:p></o:p></span></p>
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Simon, Richard,<o:p></o:p></p>
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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.<o:p></o:p></p>
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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?<o:p></o:p></p>
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Best,<o:p></o:p></p>
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Jan<o:p></o:p></p>
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[Joseph 2014] <a href="https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww2.eecs.berkeley.edu%2FPubs%2FTechRpts%2F2014%2FEECS-2014-130.pdf&data=02%7C01%7Csimonpj%40microsoft.com%7C0cef689885ed40a9696d08d41acbfd5f%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C1%7C636162910819713326&sdata=jCrF3a%2BSoTISvzA8KzGlG8AjG5iDro5SHLQr9oO%2Bv5E%3D&reserved=0" target="_blank">https://www2.eecs.berkeley.edu/Pubs/TechRpts/2014/EECS-2014-130.pdf</a><o:p></o:p></p>
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<o:p> </o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:6.0pt;margin-right:0cm;margin-bottom:6.0pt;margin-left:0cm">
2016-11-29 12:41 GMT+00:00 Simon Peyton Jones <<a href="mailto:simonpj@microsoft.com" target="_blank">simonpj@microsoft.com</a>>:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif">Jan,</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif">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.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif">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.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif">In the light of that understanding, I think rebindable syntax will be easier.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif">I don’t know if you are up for that, but it’s a rather un-tended part of GHC.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif">Thanks</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif">Simon</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-family:"Calibri",sans-serif"> </span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> ghc-devs
[mailto:<a href="mailto:ghc-devs-bounces@haskell.org" target="_blank">ghc-devs-bounces@haskell.org</a>]
<b>On Behalf Of </b>Richard Eisenberg<br>
<b>Sent:</b> 28 November 2016 22:30<br>
<b>To:</b> Jan Bracker <<a href="mailto:jan.bracker@googlemail.com" target="_blank">jan.bracker@googlemail.com</a>><br>
<b>Cc:</b> <a href="mailto:ghc-devs@haskell.org" target="_blank">ghc-devs@haskell.org</a><br>
<b>Subject:</b> Help needed: Restrictions of proc-notation with RebindableSyntax</span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">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.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Can anyone else help Jan here?<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Richard<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">On Nov 23, 2016, at 4:34 AM, Jan Bracker via ghc-devs <<a href="mailto:ghc-devs@haskell.org" target="_blank">ghc-devs@haskell.org</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Hello,<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">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.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Best,<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Jan<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">[1] <a href="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" target="_blank">https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts.html#rebindable-syntax-and-the-implicit-prelude-import</a><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">_______________________________________________<br>
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