I am not worried about the argument order because in Elixir the subject is
always the first argument. So it is always "is date1 before date2?". I like
the :inclusive option if the need ever arises.
DateTime.compare(a, :<, b) would get my vote of the alternative proposals
but I think it doesn't move much the needle in comparison to
DateTime.compare.
On Mon, Oct 31, 2022 at 5:44 PM Cliff <notcliffwilli...@gmail.com> wrote:
> 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). And
>>>>>>> also
>>>>>>> if some libraries feel compelled to expose functions such as
>>>>>>> "after_or_equal" or if users would have to write Date.equal?(date1,
>>>>>>> date2)
>>>>>>> or Date.earlier?(date1, date2), which would end-up doing the double of
>>>>>>> conversions.
>>>>>>>
>>>>>>>
>>>>>>>
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