Swap sortKeys bool for keySort function

[kevboh]

(This is a breaking change, but I can make it non-breaking if preferred. It's just a lot more code repetition if non-breaking.)

This changes the sortKeys option to be a more flexible keySort function. The function defaults to nil—do not sort—but can be anything that sorts Nodes. I ran into an issue where I wanted a custom sort on a mapping.

[jpsim]

Thanks for the PR! Could you please rebase your commits on top of main? That should fix the failing CMake CI jobs.

[kevboh]

@jpsim this has been rebased. Thanks for taking a look!

[kevboh]

@jpsim let me know if anything else is required here.

[kevboh]

Hi, is this still mergeable? If so I'd love to merge it!

[lynchsft]

Hello! I'm sorry that the communication failed in 2021. The project is under more active maintenance now.

I'm not a fan of the source-breaking change of turning sortKeys into keySort.

I do however appreciate the ability to custom-sort the keys.

This is what I propose:

Introduce a KeySort enum type with:

• a .natural case which performs the natural < sort
• a .custom((Key, Key)->Bool) case for custom sorting.
• a .none case for non-sorting.

If KeySort conforms to ExpressibleAsBooleanLitteral then true can map to .natural and false can map to .none.

With this arrangement we can gain custom sorting without breaking backward compatibility with uses of the existing sort behavior.

Thoughts?

[kevboh]

I don't write Swift professionally anymore or use this project, so I defer to you!