I would prefer the atoms *:before*, and *:after* rather than :gt/:greater_than/etc. Since we're already solving the problem of operator/argument ordering, why not remove the final mental barrier of reasoning about whether a time being "greater than" another time means that it is before or after? *foo(a, :gt, b)* still requires a second thought ("Is a bigger time earlier or later?"), whereas if I read code that said *foo(a, :before, b)* I would feel confident in my understanding after only the first read.
On Monday, October 31, 2022 at 12:35:05 PM UTC-4 lui...@gmail.com wrote: > I also prefer something like *DateTime.compare(a, operator, b)*. > > Operators don't need to be *cryptic* like *:eq*, *:gt*, *:lte*, etc., we > can use the same comparison operators we already are used to: > > *DateTime.compare(a, :<, b)* > *DateTime.compare(a, :==, b)* > *DateTime.compare(a, :>=, b)* > > It's clear and much less verbose than the Ecto's (which was a great > suggestion, by the way). > > On Monday, October 31, 2022 at 5:23:54 PM UTC+1 and...@dryga.com wrote: > >> Hey guys, as an idea why don't we reuse atoms from Ecto: >> >> - :less_than >> - :greater_than >> - :less_than_or_equal_to >> - :greater_than_or_equal_to >> - :equal_to >> - :not_equal_to >> >> I feel like they are fairly common nowadays and even though it's more to >> type make it easier to understand when you want an inclusive comparison. >> >> We can later make it part of all modules that have `compare/2` (Date, >> DateTime, Time, Version, etc). >> >> On Monday, October 31, 2022 at 10:10:09 AM UTC-6 Cliff wrote: >> >>> I prefer the form *DateTime.is(a, operator, b)*, but I agree with >>> others that it would need a more sensible name than "is". >>> >>> Regarding the form *DateTime.before?(a, b)*, I could still see myself >>> getting confused by argument order. *before?(a, b)* might be read as >>> "before A happened, B happened", rather than the intended "A happened >>> before B". the *is(a, :before, b)* form, however, is read exactly how >>> it would be spoken. >>> >>> Regarding comparison inclusivity, another possibility is a keyword >>> option: *DateTime.before?(a, b, inclusive: true)* >>> >>> On Monday, October 31, 2022 at 3:45:15 AM UTC-4 simonmc...@gmail.com >>> wrote: >>> >>>> DateTime.before?(a, b) is much nicer than DateTime.compare(a, b) == >>>> :lt. It doesn't completely remove the argument order issue but I reckon >>>> it >>>> would resolve it for me. I run DateTime.compare(a, b) in iex every time I >>>> use the function because I'm terribly forgetful and paranoid. I would >>>> prefer DateTime.eq?/lt?/le?/gt?/ge? instead of >>>> before?/after?/on_or_before?/on_or_after? which is shorter, matches >>>> compare/2 and might allow the le/ge equivalents to sneak through. I think >>>> it would be a shame to leave out le and ge. >>>> >>>> DateTime.is?/compare?(a, :lt, b) is a whole lot less ambiguous to me. >>>> It reads how you would write it in maths or spoken language. >>>> >>>> On Monday, 31 October 2022 at 5:08:35 pm UTC+10 zachary....@gmail.com >>>> wrote: >>>> >>>>> I wonder how much of the issue is the Api and how much of the issue is >>>>> just the docs? I.e its not a given that all arguments in every position >>>>> always make sense, but we typically rely on things like elixir_ls to help >>>>> us when the answer isn't obvious. >>>>> >>>>> Could we perhaps just improve the docs in some way? i.e update the >>>>> specs to say `datetime :: Calendar.datetime(), compares_to :: >>>>> Calendar.datetime()`, and have the args say `compare(datetime, >>>>> compares_to)` and have part of the first line of text say something a bit >>>>> more informative? >>>>> >>>>> >>>>> On Mon, Oct 31, 2022 at 3:02 AM, Jon Rowe <ma...@jonrowe.co.uk> wrote: >>>>> >>>>>> I'm not sure the name is right, but I like >>>>>> >>>>>> DateTime.is?(a <http://datetime.is/?(a>, operator, b), when operator >>>>>> :lt | :le | :eq | :ge | :gt, which would capture the :le and :ge options. >>>>>> >>>>>> >>>>>> As a usage api, we could actually have `compare?/3` especially as the >>>>>> name doesn't overlap with `compare/2` which would hopefully alleviate >>>>>> anyones concerns about the return type changing >>>>>> >>>>>> On Mon, 31 Oct 2022, at 6:23 AM, José Valim wrote: >>>>>> >>>>> My thought process is that a simple to use API should be the focus, >>>>>> because we already have a complete API in Date.compare/2 >>>>>> <http://date.compare/2> and friends. >>>>>> >>>>>> On Mon, Oct 31, 2022 at 02:16 Simon McConnell <simonmc...@gmail.com> >>>>>> wrote: >>>>>> >>>>>> would we want on_or_after? and on_or_before? as well then? Or >>>>>> something like DateTime.is?(a <http://datetime.is/?(a>, operator, >>>>>> b), when operator :lt | :le | :eq | :ge | :gt, which would capture the >>>>>> :le >>>>>> and :ge options. >>>>>> >>>>>> On Monday, 31 October 2022 at 7:26:42 am UTC+10 José Valim wrote: >>>>>> >>>>>> Thank you! >>>>>> >>>>>> A PR that adds before?/after? to Time, Date, NaiveDateTime, and >>>>>> DateTime is welcome! >>>>>> >>>>>> >>>>>> On Sun, Oct 30, 2022 at 6:46 PM Cliff <notcliff...@gmail.com> wrote: >>>>>> >>>>>> I did a bit of research. Many other languages use some form of >>>>>> operator overloading to do datetime comparison. The ones that do >>>>>> something >>>>>> different: >>>>>> >>>>>> - Java has LocalDateTime.compareTo(other) >>>>>> >>>>>> <https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/LocalDateTime.html#compareTo(java.time.chrono.ChronoLocalDateTime)>, >>>>>> >>>>>> returning an integer representing gt/lt/eq. There is also >>>>>> LocalDateTime.isBefore(other) >>>>>> >>>>>> <https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/LocalDateTime.html#isBefore(java.time.chrono.ChronoLocalDateTime)>, >>>>>> >>>>>> LocalDateTime.isAfter(other), and LocalDateTime.isEqual(other). The >>>>>> LocalDateTime.is <http://localdatetime.is/>{Before, After} >>>>>> methods are non-inclusive (<, >) comparisons. They are instance >>>>>> methods, so >>>>>> usage is like `myTime1.isBefore(myTime2)` >>>>>> - OCaml's "calendar" library provides a Date.compare >>>>>> >>>>>> <https://ocaml.org/p/calendar/3.0.0/doc/CalendarLib/Date/index.html#val-compare> >>>>>> >>>>>> function that returns an integer representing gt/lt/eq (for use in >>>>>> OCaml's >>>>>> List.sort function, which sorts a list according to the provided >>>>>> comparison >>>>>> function). It also provides Date.> >>>>>> >>>>>> <https://ocaml.org/p/calendar/3.0.0/doc/CalendarLib/Date/index.html#val-(%3E)>, >>>>>> >>>>>> and Date.>= >>>>>> >>>>>> <https://ocaml.org/p/calendar/3.0.0/doc/CalendarLib/Date/index.html#val-(%3E=)>, >>>>>> >>>>>> etc. Worth noting is that OCaml allows you to do expression-level >>>>>> module >>>>>> imports, like *Date.(my_t1 > my_t2)* to use Date's *>* function >>>>>> in the parenthesized expression without needing to *open Date* in >>>>>> the entire scope ("open" is OCaml's "import") - this could >>>>>> potentially be >>>>>> possible in Elixir using a macro? >>>>>> - Golang: t1.After(t2) <https://pkg.go.dev/time#Time.After>, >>>>>> t1.Before(t2), t1.Equal(t2). Non-inclusive (> and <). >>>>>> - Clojure clj-time library: (after? t1 t2) >>>>>> >>>>>> <https://clj-time.github.io/clj-time/doc/clj-time.core.html#var-after.3F>, >>>>>> >>>>>> (before? t1 t2) >>>>>> >>>>>> <https://clj-time.github.io/clj-time/doc/clj-time.core.html#var-before.3F>, >>>>>> >>>>>> and (equal? t1 t2) >>>>>> >>>>>> <https://clj-time.github.io/clj-time/doc/clj-time.core.html#var-equal.3F>. >>>>>> >>>>>> IMO the argument order is still confusing in these. >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Sunday, October 30, 2022 at 3:15:14 AM UTC-4 José Valim wrote: >>>>>> >>>>>> I am definitely in favor of clearer APIs. >>>>>> >>>>>> However, it would probably be best to explore how different libraries >>>>>> in different languages tackle this. Can you please explore this? In >>>>>> particular, I am curious to know if before/after mean "<" and ">" >>>>>> respectively or if they mean "<=" and "=>" (I assume the former). 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