It seems like the goal is just to have a shorter way to express utc_now and utc_today, because otherwise this code is the same:
Date.shift(Date.utc_today(), month: 1) Date.shift(:utc_today, month: 1) Two ideas come to mind besides supporting the atom, that would just give you a Date/DateTime to use here that could be shorter. * Change what the sigils support ~D[utc_today]/~U[utc_now] * Make utc_today/0 and utc_now/2 Kernel functions. Allen Madsen http://www.allenmadsen.com On Wed, Jan 8, 2025 at 11:39 AM Zach Daniel <zachary.s.dan...@gmail.com> wrote: > I didn't mean that we would make a struct that people could pretend was a > datetime and do things like call `.year` on it. I meant that if we are > using a "magic value" we could make the "magic value" be something that can > be expanded over time. > > For example, if I want to make a function that takes "a thing that can be > passed into `DateTime.shift`", it is much easier if I can say `DateTime.t() > | DateTime.Lazy.t()` etc. Don't we have > similar treatment for `Regex`? Like the internals aren't meant to be > pattern matched on/used, but it can be accepted by internal functions. > > If we're sure there will only ever be one such atom then I guess it makes > sense, but if I wanted go guard against "something that DateTime accepts" > it feels like `when is_struct(datetime, DateTime) or is_struct(datetime, > DateTime.Lazy)` would future proof that guard, where as `when > is_struct(datetime, DateTime) or datetime == :utc_now` wouldn't. > > On Jan 8, 2025, at 11:10 AM, José Valim <jose.va...@gmail.com> wrote: > > The problem is that the struct fields are public and we can't make them > lazy. So if the user does `DateTime.lazy(:utc_now).year`, it won't work, > and if the only use of said lazy types is to pass it to these functions, we > might as well make it an atom specific to these functions. :) > > > *José Valimhttps://dashbit.co/ <https://dashbit.co/>* > > > On Wed, Jan 8, 2025 at 4:46 PM Zachary Daniel <zachary.s.dan...@gmail.com> > wrote: > >> DateTime.shift(DateTime.lazy(:utc_now), duration) >> >> Doesn’t have the same feel of convenience but it seems to me to be a more >> resilient option. >> >> On Jan 8, 2025, at 10:44 AM, Zachary Daniel <zachary.s.dan...@gmail.com> >> wrote: >> >> >> I’m wondering if an opaque struct may be better, representing a >> computed-on-demand datetime. Like `%DateTime.Lazy{}`. Then it could grow >> over time without needing to expand a set of magic atoms. >> >> On Jan 8, 2025, at 10:37 AM, 'Billy Lanchantin' via elixir-lang-core < >> elixir-lang-core@googlegroups.com> wrote: >> >> >> I like the functionality and neither option seems like the obvious >> choice. I agree with José here: >> >> > 2. If we go [the dedicated function] route, we may find ourselves >> adding other functions, such as `add_to_utc_now` and `diff_to_utc_now`. >> >> So I somewhat favor `Date.shift(:utc_today, month: 1)`. It's naturally >> extensible to other bases (like `:now`, `:utc_now`) without polluting the >> temporal modules with helpers. >> >> The downside is that the types will be more awkward. `DateTime.shift/2` >> and friends will accept either a struct or one of a set of special atoms. >> So we're stuck increasing the either size of the types or the number >> functions. >> >> --- >> >> What does the `Date.range(date, duration)` return? >> On Wednesday, January 8, 2025 at 8:02:45 AM UTC-5 José Valim wrote: >> >>> Another scenario where :utc_now could be used is DateTime.after?(date, >>> :utc_now) >>> >>> >>> *José Valimhttps://dashbit.co/ <https://dashbit.co/>* >>> >>> >>> On Wed, Jan 8, 2025 at 1:57 PM Jon Rowe <ma...@jonrowe.co.uk> wrote: >>> >>>> I'd love either of these proposals to be a reality, I often find myself >>>> building my own helpers in tests to do this sort of thing. >>>> >>>> Initially I thought the function varient was better but if you look at >>>> it as "then we might have to add all these other functions" I found myself >>>> leaning towards allowing `:utc_now` as a placeholder in the existing api, >>>> it might be slightly more verbose but it leans towards a more compact core >>>> api overall... so that gets my +1. >>>> >>>> Cheers >>>> Jon >>>> >>>> On Wed, 8 Jan 2025, at 11:06 AM, José Valim wrote: >>>> >>>> I'd love to see something along those lines but I can't pick a favorite. >>>> >>>> 1. Supporting :utc_now in "shift" could be a welcome addition, as we >>>> could also support it in "add" and "diff" functions. However, I'd say it is >>>> more verbose than from_utc_today. >>>> >>>> 2. from_utc_now/from_utc_today is clearer but less applicable. If we go >>>> this route, we may find ourselves adding other functions, such as >>>> `add_to_utc_now` and `diff_to_utc_now`. >>>> >>>> So I would love to hear everyone's thoughts. >>>> >>>> "Date.range/2" with a duration is a no-brainer though and we could add >>>> it today. >>>> >>>> *José Valim* >>>> https://dashbit.co/ >>>> >>>> >>>> On Tue, Jan 7, 2025 at 5:43 PM Wojtek Mach <woj...@wojtekmach.pl> >>>> wrote: >>>> >>>> Hello, >>>> >>>> I'd like to propose adding the following functions: >>>> >>>> - `Date.from_utc_today(duration)` >>>> - `NaiveDateTime.from_utc_today(duration)` >>>> - `DateTime.from_utc_today(duration)` >>>> >>>> For example: >>>> >>>> # Say, now is ~U[2025-01-07 16:22:40.003901Z] >>>> >>>> iex> Date.from_utc_now(month: 1, day: 1) >>>> ~D[2025-02-08] >>>> >>>> iex> NaiveDateTime.from_utc_now(hour: -1) >>>> ~N[2025-01-07 15:22:40.003901] >>>> >>>> iex> DateTime.from_utc_now(Duration.new!(hour: 1)) >>>> ~U[2025-01-07 17:22:40.003901Z] >>>> >>>> I believe they are especially useful when writing tests and they might >>>> give opportunity for some optimizations. >>>> >>>> Another idea is to instead allow passing `:utc_today` / `:utc_now` to >>>> the existing shift/2 functions: >>>> >>>> iex> Date.shift(:utc_today, month: 1, day: 1) >>>> ~D[2025-02-08] >>>> >>>> iex> NaiveDateTime.shift(:utc_now, hour: -1) >>>> ~N[2025-01-07 15:22:40.003901] >>>> >>>> iex> DateTime.from_utc_now(:utc_now, hour: 1) >>>> ~U[2025-01-07 17:22:40.003901Z] >>>> >>>> Btw and this is a related but separate conversion, I think a >>>> `Date.range(date, duration)` would be a nice addition. And so, I believe a >>>> `Date.range(:utc_today, month: 1)` would be a natural extension of this. >>>> I'm not sure if supporting `Date.add(:utc_today, 1)` and similar is worth >>>> it, perhaps just for consistency. >>>> >>>> >>>> -- >>>> 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 visit >>>> https://groups.google.com/d/msgid/elixir-lang-core/2851ea28-d20e-4e8d-b957-38a582f7fa39n%40googlegroups.com >>>> <https://groups.google.com/d/msgid/elixir-lang-core/2851ea28-d20e-4e8d-b957-38a582f7fa39n%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-co...@googlegroups.com. >>>> To view this discussion visit >>>> https://groups.google.com/d/msgid/elixir-lang-core/CAGnRm4L9iSWc7zD8v_%2BqNhsOhx10atYksuPO5gbGCMvvz88sPA%40mail.gmail.com >>>> <https://groups.google.com/d/msgid/elixir-lang-core/CAGnRm4L9iSWc7zD8v_%2BqNhsOhx10atYksuPO5gbGCMvvz88sPA%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 visit >>>> https://groups.google.com/d/msgid/elixir-lang-core/3952efd8-06a4-4855-9277-8208b5c8068f%40app.fastmail.com >>>> <https://groups.google.com/d/msgid/elixir-lang-core/3952efd8-06a4-4855-9277-8208b5c8068f%40app.fastmail.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 visit >> https://groups.google.com/d/msgid/elixir-lang-core/d1c3407a-5c4c-4978-a813-43eaf9711554n%40googlegroups.com >> <https://groups.google.com/d/msgid/elixir-lang-core/d1c3407a-5c4c-4978-a813-43eaf9711554n%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 visit >> https://groups.google.com/d/msgid/elixir-lang-core/CF7D089E-DBB9-432A-B15D-4EB5DFB046DB%40gmail.com >> <https://groups.google.com/d/msgid/elixir-lang-core/CF7D089E-DBB9-432A-B15D-4EB5DFB046DB%40gmail.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 visit > https://groups.google.com/d/msgid/elixir-lang-core/CAGnRm4K0q1dOWpFxNH%2BxAsdJpt_G9DA-BDGJqeYxOTgD-AuDQg%40mail.gmail.com > <https://groups.google.com/d/msgid/elixir-lang-core/CAGnRm4K0q1dOWpFxNH%2BxAsdJpt_G9DA-BDGJqeYxOTgD-AuDQg%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 visit > https://groups.google.com/d/msgid/elixir-lang-core/7390B51F-96B5-44C3-8896-85B171EFB4C7%40gmail.com > <https://groups.google.com/d/msgid/elixir-lang-core/7390B51F-96B5-44C3-8896-85B171EFB4C7%40gmail.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "elixir-lang-core" group. 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