<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=""><div class=""></div><div class=""><br class=""></div><div class="">SimonPJ’s message got support from Iavor and Richard, and SimonM previously expressed support on this Round 2 thread.</div><div class=""><br class=""></div><div class="">In the meantime, the proposal has also been changed to use ’;’ as a separator (instead of the initially proposed ’|’). However, this still leaves us with</div><div class=""><br class=""></div><div class=""> <a href="https://github.com/ghc-proposals/ghc-proposals/pull/43#issuecomment-398086013" class="">https://github.com/ghc-proposals/ghc-proposals/pull/43#issuecomment-398086013</a></div><div class=""><br class=""></div><div class="">where the proposal author writes that he will update the proposal with new typing rules along SimonPJ’s suggestions within a few weeks.</div><div class=""><br class=""></div><div class="">Hence, it seems to me that we need to wait with a formal decision until that update of the typing rules has happened. Do you agree, Simon?</div><div class=""><br class=""></div><div class="">In any case, is anybody unhappy with any aspect other than ”what would and would not typecheck” (which will hopefully be addressed in those forthcoming typing rules)? If so, please speak now.</div><div class=""><br class=""></div><div class="">Cheers,</div>Manuel<br class=""><div><br class=""><blockquote type="cite" class=""><div class="">01.06.2018 17:30 Manuel M T Chakravarty <<a href="mailto:chak@justtesting.org" class="">chak@justtesting.org</a>>:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">We now have a revised version of the ”Or pattern” proposal #43 to consider:<div class=""><br class=""></div><div class=""> (formatted) <a href="https://github.com/osa1/ghc-proposals/blob/or_patterns/proposals/0000-or-" class="">https://github.com/osa1/ghc-proposals/blob/or_patterns/proposals/0000-or-</a>patterns.rst<br class=""> (PR thread) <a href="https://github.com/ghc-proposals/ghc-proposals/pull/43" class="">https://github.com/ghc-proposals/ghc-proposals/pull/43</a></div><div class=""><br class=""></div><div class="">You may remember that we discuss this a while back</div><div class=""><br class=""></div><div class=""> <a href="https://mail.haskell.org/pipermail/ghc-steering-committee/2017-November/000231.html" class="">https://mail.haskell.org/pipermail/ghc-steering-committee/2017-November/000231.html</a></div><div class=""><br class=""></div><div class="">and finally decided to bounce it back to the authors with the following recommendation:</div><div class=""><br class=""></div><div class=""> <a href="https://github.com/ghc-proposals/ghc-proposals/pull/43#issuecomment-358189327" class="">https://github.com/ghc-proposals/ghc-proposals/pull/43#issuecomment-358189327</a></div><div class=""><br class=""></div><div class="">We previously decided that we are inclined to accept this proposal if the authors change the points that we highlighted. Judging from the conversation of SimonPJ and Richard with the author on the GitHub thread, it appears to me that most of the issues have been addressed. However, Simon’s point </div><div class=""><br class=""></div><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><div class=""><div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>• "Patterns that bind existentials, dictionaries, or equalities are rejected by the type checker". I disagree. Earlier I suggested "no variable bound by an or-pattern can have a type that mentions an existential variable bound by the or-pattern". That is much more friendly because you can still match against an existential constructor; you just can’t bind an existential variable.</div></div><div class=""><br class=""></div></blockquote>from <<a href="https://github.com/ghc-proposals/ghc-proposals/pull/43#issuecomment-368933401" class="">https://github.com/ghc-proposals/ghc-proposals/pull/43#issuecomment-368933401</a>> still doesn’t seem to be addressed, or am I misunderstanding?<div class=""><br class=""></div><div class="">Overall, I propose to accept the proposal, possibly requiring that the above point be addressed.<br class=""><div class=""><br class=""></div><div class="">What do you all think?</div><div class=""><br class=""></div><div class="">Cheers,</div><div class="">Manuel</div><div class=""><br class=""></div></div></div></div></blockquote></div><br class=""></body></html>