Date/time literals

[faultyserver]

Something that I think a lot of big languages today are missing is Date literals. ISO 8601 provides an un-ambiguous syntax for specifying dates, though the individual components of the date could be construed as binary operations on integers, or map entries with integer values.

To ensure there is no ambiguity, date literals could be prefixed with a D (or DT explicitly for datetimes):

new_year = D2017-01-01
now = DT2017-06-26 4:15:30Z-05:00

Some disambiguation between optional timezone specifiers and map entry definitions is probably needed, though key interpolation would be used anyway, since a DateTime is not a symbol.

[faultyserver]

Rationale for this: ISO 8601 is pretty unanimously understood by developers. For some reason, date constructors in various languages use different parameter layouts and/or naming conventions that mean I often find myself having to lookup how to create a new Date/DateTime object, even if I've been using a language consistently for a while.

Having an explicit constructor using a unanimous format would clear up a lot of confusion and avoid having to look up parameters, etc.

[faultyserver]

So Elixir does have Date Sigils that work similarly:

~D[2017-08-23]
~N[2000-02-28 01:23:45]

This is okay in my book, but I'm not a fan of the overloaded [] notation (though I believe the punctuation can be any bracing character.

The Elixir implementation is also a runtime thing: the sigil is a function that takes a string argument that gets interpolated at runtime. In most cases, that's probably fine, and does make the whole thing more flexible, but I still think I'd like something parse-time and literal-like rather than just a wrapper for Date.new.

[Jens0512]

I think the DT2017-06-26 4:15:30Z-05:00 is a bit unclear. It just seems disjunct, the DT prefix is understandable ─ once you see it, which is not quite easy enough IMO. And also the plain white space between the date and time is a bit divergent of how all else Myst code looks.

As for the format; ISO 8601 seems like a great idea, and it makes it very clear that this is a date. But the thing is that 17 out 27 of the chars in there are numbers, people like me without optimal eyesight might quickly dismiss this as some gibberish probably decimal without actually reading it properly. It think it should stand out even more, maybe with something similar to Crystal's percent string literals i.e. things like %w(my name is Ned ) to create the array ["my", "name", "is", "Ned"], maybe in Myst we can have

%DT(2017-06-26 4:15:30Z-05:00)

If nothing else, it seems a bit clearer to me than without the parentheses and percentage sign.