Programmatic (automatic) orientation of plot axes

[grantmcdermott]

Looking at a way to address a long-standing issue. See nice post by @simonpcouch here: https://blog.simonpcouch.com/blog/ggplot-pipe-plus/

The TL;DR idea would be to define a new ggplot_add method (ggplot_add.geom_parttree?) that accesses the existing plot aesthetic mappings and then passes any axes information on to the underlying parttree call, probably through ...

This could then be used to switch on the flip_axes argument. Internal pseudo code would be something like:

if (quo_name(plot$mapping$x) == vars[2] && quo_name(plot$mapping$y) == vars[1]) flip_axes = TRUE

[grantmcdermott]

I haven't had time to implement the the new add method, but closing in light of #18.