Compared to the previous proposal, this one has been very quiet so far. :) I am unsure if it was because it was a Monday or because holidays are coming, so I am sending a ping.
ALso note I updated the proposal to not use parens around let/reduce, which seems to be the preference so far: https://gist.github.com/josevalim/fe6b0bcc728539a5adf9b2821bd4a0f5 On Tue, Dec 21, 2021 at 1:29 AM 'eksperimental' via elixir-lang-core < elixir-lang-core@googlegroups.com> wrote: > Not necessarily that they are replaceable, > but that pattern of :cont, :halt, :suspend is most commonly used via > Enumerable.reduce > > > On Mon, 20 Dec 2021 19:18:53 -0500 > "'eksperimental' via elixir-lang-core" > <elixir-lang-core@googlegroups.com> wrote: > > > > I have found only one usage of Enum.reduce_while in Elixir's > > > codebase. > > > > This is because under the hood Enum.reduce_while is a call > > `Enumerable.reduce/3`, so we are invoking this functions direcly. > > > > > On Tue, 21 Dec 2021 00:47:44 +0100 > > Stefan Chrobot <ste...@chrobot.io> wrote: > > > > > Thanks, that version would work, but agreed - not sure how big of an > > > improvement that would be over Enum.reduce_while. Trying to think > > > about this in a more imperative style, it seems that maybe an > > > equivalent of break is what I'm after? Maybe something close to > > > Ecto's Repo.transaction semantics? > > > > > > for foo <- foos do > > > case barify(foo) do > > > {:ok, bar} -> bar > > > {:error, reason} -> break(reason) > > > end > > > end > > > > > > I think this would have to work similarly to how Ecto's transactions > > > work with Multis, that is return {:ok, bars} or {:error, reason, > > > data_so_far}. > > > > > > I have found only one usage of Enum.reduce_while in Elixir's > > > codebase. Interestingly, the shape of the return value is always > > > the same - a list of finished tests. > > > > https://github.com/elixir-lang/elixir/blob/main/lib/ex_unit/lib/ex_unit/runner.ex#L340 > > > > > > This seems like a separate problem, but maybe something to keep in > > > mind. > > > > > > Best, > > > Stefan > > > > > > > > > wt., 21 gru 2021 o 00:21 Ben Wilson <benwilson...@gmail.com> > > > napisał(a): > > > > > > > To revisit the example situation from the original post: > > > > > > > > ``` > > > > {sections, _acc} = > > > > for let {section_counter, lesson_counter} = {1, 1}, section <- > > > > sections do lesson_counter = if section["reset_lesson_position"], > > > > do: 1, else: lesson_counter > > > > {lessons, lesson_counter} = for let lesson_counter, lesson <- > > > > section["lessons"] do > > > > {Map.put(lesson, "position", lesson_counter), lesson_counter + 1} > > > > end > > > > section = > > > > section > > > > |> Map.put("lessons", lessons) > > > > |> Map.put("position", section_counter) > > > > > > > > {section, {section_counter + 1, lesson_counter}} > > > > end > > > > ``` > > > > > > > > I think that's nice! It focuses on inputs and outputs and reduces > > > > the overall line noise. > > > > > > > > On Monday, December 20, 2021 at 5:28:29 PM UTC-5 José Valim wrote: > > > > > > > >> Stefan, this would work if we include all extensions: > > > >> > > > >> for reduce {status, acc} = {:ok, []}, status == :ok, foo <- foos > > > >> do case barify(foo) do > > > >> {:ok, bar} -> {:ok, [bar | acc]} > > > >> > > > >> {:error, _reason} = error -> error > > > >> end > > > >> end > > > >> > > > >> I am not sure if you find it any better. It is hard to do this > > > >> with "let" because you don't want to include the element of when > > > >> it fails. > > > >> > > > >> On Mon, Dec 20, 2021 at 9:23 PM Stefan Chrobot > > > >> <ste...@chrobot.io> wrote: > > > >>> I went through some of our code and one thing I'd love to see is > > > >>> a way to replace Enum.reduce_while with the for comprehension. > > > >>> So the code like this: > > > >>> > > > >>> Enum.reduce_while(foos, {:ok, []}, fn foo, {:ok, bars} -> > > > >>> case barify(foo) do > > > >>> {:ok, bar} -> {:cont, {:ok, [bar | bars]}} > > > >>> {:error, _reason} = error -> {:halt, error} > > > >>> end > > > >>> end) > > > >>> > > > >>> Would the following even work? > > > >>> > > > >>> for reduce(result = {:ok, []}), foo <- foos, {:ok, _} <- result > > > >>> do case barify(foo) do > > > >>> {:ok, bar} -> {{:ok, [bar | bars]}} > > > >>> {:error, _reason} = error -> {error} > > > >>> end > > > >>> end > > > >>> > > > >>> Even if it did, it's not doing a great job of communicating the > > > >>> intent and still potentially requires a Enum.reverse call. The > > > >>> intent here is "early exit with some value upon some condition > > > >>> or pattern mismatch". > > > >>> > > > >>> > > > >>> Best, > > > >>> Stefan > > > >>> > > > >>> pon., 20 gru 2021 o 21:06 Stefan Chrobot <ste...@chrobot.io> > > > >>> napisał(a): > > > >>>> I really like this proposal! For me it strikes the perfect > > > >>>> balance between terseness and explicitness that I've come to > > > >>>> enjoy in Elixir. > > > >>>> > > > >>>> My votes: > > > >>>> - Naming: let over given; just because it's shorter, > > > >>>> - Do use parents: let "feels" similar to var!. > > > >>>> > > > >>>> Best, > > > >>>> Stefan > > > >>>> > > > >>>> pon., 20 gru 2021 o 19:54 José Valim <jose....@dashbit.co> > > > >>>> napisał(a): > > > >>>>> Good point. I forgot to mention the :reduce option will be > > > >>>>> deprecated in the long term. > > > >>>>> > > > >>>>> On Mon, Dec 20, 2021 at 7:53 PM 'eksperimental' via > > > >>>>> elixir-lang-core < elixir-l...@googlegroups.com> wrote: > > > >>>>> > > > >>>>>> The proposal is very concise, > > > >>>>>> the only thing that would be problematic is the use of > > > >>>>>> `reduce` for two > > > >>>>>> different things, > > > >>>>>> > > > >>>>>> for <<x <- "AbCabCABc">>, x in ?a..?z, reduce: %{} do > > > >>>>>> acc -> Map.update(acc, <<x>>, 1, & &1 + 1) > > > >>>>>> end > > > >>>>>> > > > >>>>>> {sum, count} = > > > >>>>>> for reduce({sum, count} = {0, 0}), i <- [1, 2, 3] do > > > >>>>>> sum = sum + i > > > >>>>>> count = count + 1 > > > >>>>>> {sum, count} > > > >>>>>> end > > > >>>>>> > > > >>>>>> It would lead to misunderstanding as it may not be clear > > > >>>>>> which one we are talking about when we say "use for reduce" > > > >>>>>> > > > >>>>>> > > > >>>>>> On Mon, 20 Dec 2021 19:11:54 +0100 > > > >>>>>> José Valim <jose....@dashbit.co> wrote: > > > >>>>>> > > > >>>>>> > Hi everyone, > > > >>>>>> > > > > >>>>>> > This is the second proposal for-let. You can find it in a > > > >>>>>> > gist: > > > >>>>>> > > https://gist.github.com/josevalim/fe6b0bcc728539a5adf9b2821bd4a0f5 > > > >>>>>> > > > > >>>>>> > Please use the mailing list for comments and further > > > >>>>>> > discussion. Thanks for all the feedback so far! > > > >>>>>> > > > > >>>>>> > > > >>>>>> -- > > > >>>>>> You received this message because you are subscribed to the > > > >>>>>> Google Groups "elixir-lang-core" group. > > > >>>>>> To unsubscribe from this group and stop receiving emails from > > > >>>>>> it, send an email to elixir-lang-co...@googlegroups.com. > > > >>>>>> To view this discussion on the web visit > > > >>>>>> > https://groups.google.com/d/msgid/elixir-lang-core/61c0d119.1c69fb81.af520.c181SMTPIN_ADDED_MISSING%40gmr-mx.google.com > > > >>>>>> . > > > >>>>>> > > > >>>>> -- > > > >>>>> You received this message because you are subscribed to the > > > >>>>> Google Groups "elixir-lang-core" group. > > > >>>>> To unsubscribe from this group and stop receiving emails from > > > >>>>> it, send an email to elixir-lang-co...@googlegroups.com. > > > >>>>> To view this discussion on the web visit > > > >>>>> > https://groups.google.com/d/msgid/elixir-lang-core/CAGnRm4LOyoAmXULJQo%2BYX4eFVJZJAoYtKHytoHujCS_kJ6AEuA%40mail.gmail.com > > > >>>>> < > https://groups.google.com/d/msgid/elixir-lang-core/CAGnRm4LOyoAmXULJQo%2BYX4eFVJZJAoYtKHytoHujCS_kJ6AEuA%40mail.gmail.com?utm_medium=email&utm_source=footer > > > > > >>>>> . > > > >>>>> > > > >>>> -- > > > >>> You received this message because you are subscribed to the > > > >>> Google Groups "elixir-lang-core" group. > > > >>> To unsubscribe from this group and stop receiving emails from > > > >>> it, send an email to elixir-lang-co...@googlegroups.com. > > > >>> > > > >> To view this discussion on the web visit > > > >>> > https://groups.google.com/d/msgid/elixir-lang-core/CACzMe7aXBL1jNM_aWmJJzYOjrK%3Dtf-4%2BLPLJLpccu_G4zr0cAg%40mail.gmail.com > > > >>> < > https://groups.google.com/d/msgid/elixir-lang-core/CACzMe7aXBL1jNM_aWmJJzYOjrK%3Dtf-4%2BLPLJLpccu_G4zr0cAg%40mail.gmail.com?utm_medium=email&utm_source=footer > > > > > >>> . > > > >>> > > > >> -- > > > > You received this message because you are subscribed to the Google > > > > Groups "elixir-lang-core" group. > > > > To unsubscribe from this group and stop receiving emails from it, > > > > send an email to elixir-lang-core+unsubscr...@googlegroups.com. > > > > To view this discussion on the web visit > > > > > https://groups.google.com/d/msgid/elixir-lang-core/c1fea9e2-f47c-4236-812a-431bc7d76d62n%40googlegroups.com > > > > < > https://groups.google.com/d/msgid/elixir-lang-core/c1fea9e2-f47c-4236-812a-431bc7d76d62n%40googlegroups.com?utm_medium=email&utm_source=footer > > > > > > . > > > > > > > > > > > -- > You received this message because you are subscribed to the Google Groups > "elixir-lang-core" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to elixir-lang-core+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/elixir-lang-core/61c11ffb.1c69fb81.9b607.f827SMTPIN_ADDED_MISSING%40gmr-mx.google.com > . > -- You received this message because you are subscribed to the Google Groups "elixir-lang-core" group. 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