Dewey Dunnington

Yes! I was surprised that guides were S3 when I opened up that code. I think it will be less work to do this after #3322, which is to say,...

Famous last words! I think a guide extension is the way to go about this (actually, I think regular second axes should use this as well). It's not future proof...

I did a PR that implemented `layer_params` (#3170) but closed it this summer because I thought it was an ugly solution. Hadley also noted this in the original thread (https://github.com/tidyverse/ggplot2/issues/3116#issuecomment-465756191)....

(My unqualified two cents is that something like `theme_get("key")` should be available globally, and that all the scales should be in the `Layout` or `panel_params`)

Definitely my code! I'll have a look at this tomorrow.

Ok...I did a bit of sleuthing. I'm going to suggest that this not get fixed until (1) second axes have been deprecated in favour of axis guides (with a transform)...

I'm far removed from this to have a quick answer other than that I recall that the intention was to use the guide axis framework for the other Coord subclasses...

Yes, likely much easier! `$get_breaks()` is probably what should be used.

I believe that is still held up on a decision about layer-specific scales. I don't understand layer-specific scales, so I don't know where it stands. If there are no layer-specific...

Just a quick note...that could partially be fixed by removing break censoring in `ScaleContinuous$get_breaks()`. `scales::extended_breaks()` often returns breaks that are outside the limits, and `scales::log_breaks()` I'm sure could be modified...