[To discuss] Explain the difference between arithmetic- and storage- primitive types

[qwwdfsad]

It would be nice to explain and provide recommendations regarding usages of various types in public API.

The overall recommendations should make a clear distinction between arithmetic types (e.g. Int, Long and Double, ones that folks do arithmetics around) and storage types (e.g. Short, Byte, Float, ones that are rather a memory layout optimization), as well as provide a recommendation what should be used in public's API and why ~Also let's deprecate Char while we are here~

[dkhalanskyjb]

An interesting case is things that are denoted with numbers, but are primarily used as symbols.

• Is the numeric ID of a document storage data or arithmetic data?
  • What if the IDs are assigned sequentially?
• Is the string 20230424 (a single-number representation of today's date) storage data?
• What about things that permit some arithmetic on them but only partially? Whereas a human can get away with fuzzy arithmetic, a computer may not have that privilege.
  • For example, clock readings: sure, typically, there are ten hours between 10:32 and 20:32, but on some days, in some timezones, with DST transitions, it may not be universally so.
  • Even just days of the month: sure, there are exactly seven days between Nov. 2nd and Nov. 9th, but the number of days between the 24th of February and the 10th of March is undefined.

[asm0dey]

@dkhalanskyjb I believe that timestamps are API types (for example, LocalDateTime), while their storage counterparts could be very different (for example, most probably DBs will store them as Longs).

I would go with API, not arithmetic types if we're talking naming.

[asm0dey]

I have a different question: if our API type is Integer, while storage is in, say Shorts, don't we make our application more fragile?

[dkhalanskyjb]

@asm0dey, you can find things like 20240102L flying across API endpoints, which are not LocalDateTime instances but also aren't arithmetic numbers.

[asm0dey]

This is definitely something I would not recommend to in the guide :)