<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Jul 24, 2021, at 7:47 AM, Simon Marlow <<a href="mailto:marlowsd@gmail.com" class="">marlowsd@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class="">OK I finished reading it again. Overall I like it because it's just name resolution; this is entirely in keeping with Haskell as it stands, and limits the interaction with current and future language features. As a smooth extension of the language I think it works nicely.</div><br class=""><div class="">I rather like the idea of "data qualified" and "class qualified", perhaps because similar ideas work out quite well in other languages (e.g. C++).<br class=""></div><div class=""><br class=""></div><div class="">Just one thing concerns me. I don't think this is necessarily a blocker, but it makes me vaguely uneasy.<br class=""></div><div class=""><br class=""></div><div class=""><div class="">Currently, if I see an identifier "M.x", I can search for "M" and be sure to find it in the import list somewhere, either as "import M" or "import X as M". I suspect a lot of people rely on this, and some coding styles strongly encourage the use of qualified names for this reason. Exporting qualified names and unfortunately breaks this property - any import can bring into scope qualified names.<br class=""></div><div class=""><br class=""></div><div class="">The property could be recovered by requiring the explicit import of qualified names (import Data.Set (module Set, ..) or something like that) but that doesn't seem very appealing either. Curious whether other people are worried about this and/or have any suggestions.</div></div></div></div></blockquote><div><br class=""></div><div>This is true -- but it's simply a problem of unqualified imports. I can always have `import qualified Data.Set as S` and then use `S.Set`. The problem would be if `Data.Set` exports qualified names like `Set.fromList`. Now, if `Data.Set` is itself imported qualified, we have `S.Set.fromList`, which is unfortunate.</div><div><br class=""></div><div>One idea could be a new import item `import module M impspec` which behaves just like `module M impspec`, but without the use of `qualify` in its interpretation. In code:</div><div><br class=""></div><div></div><blockquote type="cite" class=""><div>interpretImpItem('import' 'module' modids impspec, export_env)</div><div> = interpretImpSpec(impspec, strip(modids, export_env))</div><div>interpretImpItem('import' 'module' modids, export_env)</div><div> = strip(modids, export_env)</div></blockquote><div><br class=""></div><div>Now, we could say</div><div><br class=""></div><div>> import qualified Data.Set ( import module Set ) as S</div><div><br class=""></div><div>which would bring e.g. `S.Set` and `S.fromList` into scope.</div><div><br class=""></div><div>This new `import module` import item would enable this idiom. (This is all possible with the proposal as stated, but not nearly as easily.) Would that help? Then, someone who cared about the property you want would be able to suggest a coding style that would maintain it.</div><div><br class=""></div><div>Richard</div><div><br class=""></div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""><br class=""><div class="">Cheers</div><div class="">Simon<br class=""></div><div class=""><br class=""></div></div></div><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, 23 Jul 2021 at 11:00, Simon Marlow <<a href="mailto:marlowsd@gmail.com" class="">marlowsd@gmail.com</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr" class=""><div class="">Just so I'm not completely silent: in the past I was generally in favour but had some suggestions. It looks like the proposal has undergone a lot of rewrites since I last reviewed it (or perhaps I just don't remember it all that well), I've started to go through it again but this is a biggie! <br class=""></div><div class=""><br class=""></div><div class="">I think a deadline is a good idea.<br class=""></div><br class=""><div class="">Cheers</div><div class="">Simon<br class=""></div></div><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, 23 Jul 2021 at 07:23, Spiwack, Arnaud <<a href="mailto:arnaud.spiwack@tweag.io" target="_blank" class="">arnaud.spiwack@tweag.io</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr" class=""><div dir="ltr" class=""><div class="">Dear all,</div><div class=""><br class=""></div><div class="">I know that this proposal is a bit long, but it also deserves your attention.</div><div class=""><br class=""></div><div class="">I feel it's going to be easier to set a bit of time to review the proposal if I give a deadline. So let's say the following: I'll be on holiday starting two weeks from now (6th August), can I have everybody's opinion by then?</div><div class=""><br class=""></div><div class="">---</div><div class=""><br class=""></div><div class="">Recapitulating the opinions so far</div><div class=""><ul class=""><li class="">I'm personally pretty enthusiastic about the entire proposal</li><li class="">Tom voiced quite enthusiastic support for what Simon PJ calls (1), and (3)</li><li class="">Simon PJ wants (1), is not against (2), is mildly against (3)</li><li class="">Joachim suspends his judgement (which is fine, but hopefully not too many of us do this :-) ).<br class=""></li></ul></div></div><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Jul 21, 2021 at 2:30 PM Simon Peyton Jones <<a href="mailto:simonpj@microsoft.com" target="_blank" class="">simonpj@microsoft.com</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div lang="EN-GB" class="">
<div class=""><p class="MsoNormal"><span class="">To be clear, I’m ok with (1), luke-warm on (2), and mildly against (3)<u class=""></u><u class=""></u></span></p>
<ol type="1" start="1" class="">
<li class="MsoNormal">
Import and export of qualified names. This seems like the Main Point.<u class=""></u><u class=""></u></li><li class="MsoNormal">
Local import (in a let/where). This seems low pain but low gain.<u class=""></u><u class=""></u></li><li class="MsoNormal">
Local modules. This is the one I'm struggling with.<u class=""></u><u class=""></u></li></ol><p class="MsoNormal"><span class="">There is more on the (tail end of the) PR
<a href="https://github.com/ghc-proposals/ghc-proposals/pull/283" target="_blank" class="">https://github.com/ghc-proposals/ghc-proposals/pull/283</a><u class=""></u><u class=""></u></span></p><p class="MsoNormal"><span class=""><u class=""></u> <u class=""></u></span></p><p class="MsoNormal"><span class="">I am open to being educated.<u class=""></u><u class=""></u></span></p><p class="MsoNormal"><span class=""><br class="">
I would love to hear from other members of the committee. Tom’s thumbs-up seemed to about (1), without saying anything about (2) and (3).<u class=""></u><u class=""></u></span></p><p class="MsoNormal"><span class=""><u class=""></u> <u class=""></u></span></p><p class="MsoNormal"><span class="">One mechanism (if my categorisation is correct) could be to ask everyone to vote (yes/no/maybe) on all of 1,2,3.<u class=""></u><u class=""></u></span></p><p class="MsoNormal"><span class=""><u class=""></u> <u class=""></u></span></p><p class="MsoNormal"><span class="">Arnaud, you are our shepherd. Your sheep await your command.<u class=""></u><u class=""></u></span></p><p class="MsoNormal"><span class=""><u class=""></u> <u class=""></u></span></p><p class="MsoNormal"><span class="">Simon<u class=""></u><u class=""></u></span></p><p class="MsoNormal"><span class=""><u class=""></u> <u class=""></u></span></p>
<div style="border-color:currentcolor currentcolor currentcolor blue;border-style:none none none solid;border-width:medium medium medium 1.5pt;padding:0cm 0cm 0cm 4pt" class="">
<div class="">
<div style="border-color:rgb(225,225,225) currentcolor currentcolor;border-style:solid none none;border-width:1pt medium medium;padding:3pt 0cm 0cm" class=""><p class="MsoNormal"><b class=""><span lang="EN-US" class="">From:</span></b><span lang="EN-US" class=""> ghc-steering-committee <<a href="mailto:ghc-steering-committee-bounces@haskell.org" target="_blank" class="">ghc-steering-committee-bounces@haskell.org</a>>
<b class="">On Behalf Of </b>Richard Eisenberg<br class="">
<b class="">Sent:</b> 19 July 2021 21:18<br class="">
<b class="">To:</b> Spiwack, Arnaud <<a href="mailto:arnaud.spiwack@tweag.io" target="_blank" class="">arnaud.spiwack@tweag.io</a>><br class="">
<b class="">Cc:</b> GHC Steering Committee <<a href="mailto:ghc-steering-committee@haskell.org" target="_blank" class="">ghc-steering-committee@haskell.org</a>><br class="">
<b class="">Subject:</b> Re: [ghc-steering-committee] #283: Local modules (again), recommendation: accept<u class=""></u><u class=""></u></span></p>
</div>
</div><p class="MsoNormal"><u class=""></u> <u class=""></u></p><p class="MsoNormal">Any thoughts on this? Simon PJ seems lukewarm (or maybe even cooler than that), Arnaud is in support, but the rest of you have been quiet.<u class=""></u><u class=""></u></p>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">Thanks!<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">Richard<u class=""></u><u class=""></u></p>
<div class="">
<div class=""><p class="MsoNormal"><br class="">
<br class="">
<u class=""></u><u class=""></u></p>
<blockquote style="margin-top:5pt;margin-bottom:5pt" class="">
<div class=""><p class="MsoNormal">On Jun 11, 2021, at 3:05 AM, Spiwack, Arnaud <<a href="mailto:arnaud.spiwack@tweag.io" target="_blank" class="">arnaud.spiwack@tweag.io</a>> wrote:<u class=""></u><u class=""></u></p>
</div><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
<div class="">
<div class="">
<div class=""><p class="MsoNormal">Dear all,<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">Let me raise this proposal again. Very few of us have opined, and while I'd usually be happy to consider silence as assent, this is a rather large proposal which may require a few more pairs of eyes. Please consider giving this one a read
and share your thoughts. If you can't do so right now, please let me know when you will be able to, so that we can plan accordingly.<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">This is an important proposal, I'm keen on seeing its design finalised.<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">/Arnaud<u class=""></u><u class=""></u></p>
</div>
</div><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
<div class="">
<div class=""><p class="MsoNormal">On Wed, May 26, 2021 at 2:35 PM Richard Eisenberg <<a href="mailto:rae@richarde.dev" target="_blank" class="">rae@richarde.dev</a>> wrote:<u class=""></u><u class=""></u></p>
</div>
<blockquote style="border-color:currentcolor currentcolor currentcolor rgb(204,204,204);border-style:none none none solid;border-width:medium medium medium 1pt;padding:0cm 0cm 0cm 6pt;margin-left:4.8pt;margin-right:0cm" class="">
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
<div class=""><p class="MsoNormal"><br class="">
<br class="">
<u class=""></u><u class=""></u></p>
<blockquote style="margin-top:5pt;margin-bottom:5pt" class="">
<div class=""><p class="MsoNormal">On May 26, 2021, at 3:28 AM, Spiwack, Arnaud <<a href="mailto:arnaud.spiwack@tweag.io" target="_blank" class="">arnaud.spiwack@tweag.io</a>> wrote:<u class=""></u><u class=""></u></p>
</div><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
<div class="">
<div class=""><p class="MsoNormal">I'm realising that I inverted additional options 1 and 3 in my reply. To spell things out: I'm in favour of the namespace introduced for every datatype and such; and weakly in favour of anonymous modules, for which I prefer the `_` syntax
than simply omitting the name.<u class=""></u><u class=""></u></p>
</div>
</div>
</blockquote>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">Oh, good. I was very confused here, but I decided not to push on it. I'm similarly weakly in favor of (1), but I can't get myself to decide firmly on whether to go with alternative (7). Going with (7) is a little more consistent with other
features, but it adds more symbols to the source text that could otherwise be omitted. So I'm pretty ambivalent.<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">Richard<u class=""></u><u class=""></u></p>
</div><p class="MsoNormal"><br class="">
<br class="">
<u class=""></u><u class=""></u></p>
<blockquote style="margin-top:5pt;margin-bottom:5pt" class="">
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
<div class="">
<div class=""><p class="MsoNormal">On Tue, May 25, 2021 at 11:54 PM Richard Eisenberg <<a href="mailto:rae@richarde.dev" target="_blank" class="">rae@richarde.dev</a>> wrote:<u class=""></u><u class=""></u></p>
</div>
<blockquote style="border-color:currentcolor currentcolor currentcolor rgb(204,204,204);border-style:none none none solid;border-width:medium medium medium 1pt;padding:0cm 0cm 0cm 6pt;margin-left:4.8pt;margin-right:0cm" class="">
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
<div class=""><p class="MsoNormal"><br class="">
<br class="">
<u class=""></u><u class=""></u></p>
<blockquote style="margin-top:5pt;margin-bottom:5pt" class="">
<div class=""><p class="MsoNormal">On May 25, 2021, at 3:09 PM, Alejandro Serrano Mena <<a href="mailto:trupill@gmail.com" target="_blank" class="">trupill@gmail.com</a>> wrote:<u class=""></u><u class=""></u></p>
</div><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
<div class="">
<div class=""><p class="MsoNormal"><span style="font-size:9pt;font-family:"Helvetica",sans-serif" class="">- I am not sure of the benefit of allowing (1), compared with the possible surprise of users.<u class=""></u><u class=""></u></span></p>
</div>
<div class=""><p class="MsoNormal"><span style="font-size:9pt;font-family:"Helvetica",sans-serif" class="">- I do not fully understand (2).<u class=""></u><u class=""></u></span></p>
</div>
<div class=""><p class="MsoNormal"><span style="font-size:9pt;font-family:"Helvetica",sans-serif" class="">- I think (3) would be great, if we ensure that nothing changes if I don’t use “qualified”, even if -XLocalModules is on.<u class=""></u><u class=""></u></span></p>
</div>
</div>
</blockquote>
</div><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
<div class=""><p class="MsoNormal">If in the language, I would use (1) -- anonymous local modules -- regularly, when defining a function or class instance with a bunch of "local" helper functions. Of course, if we can't omit the module name, I will suffer no great harm.<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">I cannot offer the guarantee you seek in (3), but I don't think you want it. (If nothing changes, then the feature has no effect!) Here is a scenario where (3) could cause trouble:<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<blockquote style="margin-top:5pt;margin-bottom:5pt" class="">
<div class=""><p class="MsoNormal">import Data.Set as Set ( abcde )<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">data Set = Mk { abcdf :: Int }<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">blah = Set.abcdf<u class=""></u><u class=""></u></p>
</div>
</blockquote>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">Previously, GHC would have suggested that you perhaps misspelled abcde. Now, you'll get (presumably) a type error.<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">Here's another case:<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<blockquote style="margin-top:5pt;margin-bottom:5pt" class="">
<div class=""><p class="MsoNormal">import Data.Set as Set ( Set )<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">data Set = Mk<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">x :: Set.Set<u class=""></u><u class=""></u></p>
</div>
</blockquote>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">Everything is happy today, but with -XLocalModules (and (3)), the type of x is an ambiguous name.<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">Any example that causes trouble, though, will have something in common: an imported module name (possibly via an alias) that matches a locally defined type name. I would imagine this pattern is rare in practice, and that the benefit of
(3) would outweigh the number of times that a problem like this bites.<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">I, too, could live without (2).<u class=""></u><u class=""></u></p>
</div>
<div class=""><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
<div class=""><p class="MsoNormal">Richard<u class=""></u><u class=""></u></p>
</div>
</div>
</blockquote>
</div>
</div>
</blockquote>
</div><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
</blockquote>
</div>
</div>
</blockquote>
</div><p class="MsoNormal"><u class=""></u> <u class=""></u></p>
</div>
</div>
</div>
</div>
</div>
</blockquote></div></div>
_______________________________________________<br class="">
ghc-steering-committee mailing list<br class="">
<a href="mailto:ghc-steering-committee@haskell.org" target="_blank" class="">ghc-steering-committee@haskell.org</a><br class="">
<a href="https://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-steering-committee" rel="noreferrer" target="_blank" class="">https://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-steering-committee</a><br class="">
</blockquote></div>
</blockquote></div>
</div></blockquote></div><br class=""></body></html>