New Ranges Feature

[ferdinandkeller]

I've started to implement proper ranges for the library. This pull request is not one that is ready to be merged with the main branch. Many functions don't have an implementation yet, and it still lacks some features I would like to add. But I would like some feedback before progressing in the direction I am going.

What is new

Here is a quick summary of what is present:

• Extention of the OffsetDateTime struct, adding functions likes floor_seconds(), ceil_seconds() and next_second(). They are necessary to the OffsetDateTimeRangeExt.
• Extension of the Range<OffsetDateTime> struct with functions like days(), full_days(), overlapping_days(), intersection(), union(), ...
• Extension of &[Range<OffsetDateTime>] slices (no functions implemented yet).

Important notes about ranges:

• You need two OffsetDateTime to create one range, so it was decided that the ranges will always work with the offset of the start datetime.
• If the ranges are reversed (end < start), most methods on this range will return None or an empty Vec.

Questions I might have

Should ranges implement the Copy trait ? The struct Range<OffsetDateTime> never changes, and doesn't implement the Iterator trait, so there shouldn't be any problem with this. I would like your feedback on the idea.

EDIT: You can't implement the Copy trait, as the Range struct is not defined inside the crate.

Coming improvements

• Implementing missing functions
• Implementing OffsetDateTimeExt for RangeInclusive
• Parsing & Formatting for ranges
• More unit tests
• Double sided iterators
• Range creation macro ?
• Similar functions for millis, micros and nanos ?

[codecov[bot]]

Codecov Report

Merging #524 (3e9c728) into main (01ca01a) will decrease coverage by 1.6%. The diff coverage is 80.8%.

@@           Coverage Diff           @@
##            main    #524     +/-   ##
=======================================
- Coverage   98.4%   96.8%   -1.6%     
=======================================
  Files         76      77      +1     
  Lines       8215    9091    +876     
=======================================
+ Hits        8082    8797    +715     
- Misses       133     294    +161     

Impacted Files	Coverage Δ
time/src/lib.rs	100.0% <ø> (ø)
time/src/offset_date_time_range.rs	76.0% <76.0%> (ø)
time/src/offset_date_time.rs	99.7% <99.4%> (-0.3%)	:arrow_down:
time/src/util.rs	100.0% <0.0%> (ø)
time/src/duration.rs	100.0% <0.0%> (ø)
time/src/format_description/parse/lexer.rs	100.0% <0.0%> (ø)
time/src/format_description/parse/ast.rs	94.0% <0.0%> (+0.2%)	:arrow_up:
time/src/format_description/parse/mod.rs	97.0% <0.0%> (+0.4%)	:arrow_up:
time/src/sys/local_offset_at/unix.rs	40.0% <0.0%> (+14.4%)	:arrow_up:

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[jhpratt]

Just a heads up, it'll probably be a few days before I get to looking at this.

[ferdinandkeller]

Don't look too deep in the methods implementation for now. There will be some work later on to make sure all the functions work properly, but for now many are not implemented, and some are implemented with errors. But even though I am doing a lot of fixes right now, the way the feature behaves hasn't changed much. I hope you find the feature coherent and pleasant to use.

[jhpratt]

Yeah, when I get around to it (possibly this coming weekend), I'll be looking at the public API, not the implementation.

[jhpratt]

After a quick review of the public API, I'm honestly impressed that you managed to get this working — it's a complicated thing to manage. With that said, I am (unfortunately) closing this pull request, as I feel it's far too large for me to manage at this point in time. I am quite busy working on language-related matters, so any issues that pop up would require me to spend time that I don't have.

Thank you for your contribution regardless! If/when I come around to having iterator helpers, I will definitely look at this code for guidance.