Editorial: Rewrite DifferenceISODate as a clearer algorithm #2762
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The DifferenceISODate AO was a port from optimized JS to spec language, but was difficult to understand. Replace it with an algorithm that is written in an easier to understand way, but produces identical results (verified by testing a 1:1 implementation of the old and new algorithms on every possible pair of dates in a 4-year period.)
The reference code is also changed to match the AO more closely and be easier to understand, although some optimizations are made.
(This is the editorial part of #2759.)