Support for years before 1583 and 1: Currently some calculations results are wrong that far into the past

[isenberg]

I'm currently using SwiftAA for calculations before the year 1583 and even before the year 1. Added some fixes already for that and currently still using some workarounds on my application side which I work on to get into a PR for SwiftAA.

My existing PR so far about this topic: #133 #136

I'll add the other soon when I have them released.

My application is mostly using rise and transit calculations. If anyone here has suggestions for improvements there for past years or comments to my PRs please let me know.

[isenberg]

In case others are wondering: Swift Date objects or more likely DateComponents only work back to the year 4713 BC. I needed to replace some with KPCAA functions.

[isenberg]

Added another fix to that PR #136 as Swift Date is for some functions not supporting years before Julian Day 0 which was used in SwiftAA. Example:

import Foundation
let initComponents = DateComponents(era: 0, year: 5000, month: 1, day: 1, hour: 12, minute: 0, second: 0, nanosecond: 0)
let cal = Calendar(identifier: .gregorian)
let date = cal.date(from: initComponents)!
let outComponents = cal.dateComponents([.era, .year], from: date)
print("\(date)")
print("\(outComponents)")

% swift DateTest.swift
-4999-01-01 19:52:58 +0000
era: 0 year: 4713 

[onekiloparsec]

Thank @isenberg ! I've merged your 4 PRs. I guess we can consider this issue fixed?

Since you seem to be deep inside the project, could you have a look at this #126 ? Just asking, but I am unable to spend more time on SwiftAA right now. Let me know when I should tag a new version.

[isenberg]

Thanks for merging! Yes, can be considered fixed.
In my next app release I'll look closer into results before Julian Day 0 as the rise-transit-set shows strange results there, while other functions for providing locations work fine. Will create a separate issue for that later.

The sun location part of #126 could indeed fall into the same category, will look into that when I work on the release after the next. If anyone is interesting of trying out my app, send me a PM and I'll return a free iOS testflight link.