Generalize plots from 2 to 3 perspectives

[hneth]

Many riskyr plots (e.g., plot_fnet, plot_tree, and plot_mosaic) currently allow choosing between 2 perspectives (by splitting the population into 2 sub-groups by either condition or decision, i.e., by = "cd" vs. by = "dc"). Adding accuracy (by = "ac") as a 3rd perspective would support 3 x 2 different versions of each plot.

[hneth]

Quick progress report:

• The new plotting functions (e.g., plot_bar) now accept and show all 3 perspectives (i.e., by = "cd", by = "dc", by = "ac").

• Functions that split a population by 2 perspectives (e.g., plot_area, plot_prism, and plot_tab) accept all pairs of perspectives (i.e., by = "cddc", by = "cdac", etc.), resulting in a large number of corresponding plot versions.

Yet to be implemented is a reduced version of plot_prism (and possibly other functions) that only takes 1 perspective (e.g., by = "cd") and shows the corresponding tree (as in plot_bar).

[hneth]

Progress has been made

The generalization from 2 to 3 perspectives (i.e., viewing the population by condition cd, by decision dc, or by accuracy ac) has consistently been implemented in the following functions:

• plot_prism, now showing either 1 or 2 perspectives at once,
• plot_area and plot_tab, showing various 2x2 views,
• plot_bar, showing either 3 or 5 sub-divisions at once, and
• plot_icons, now showing 3 ways of grouping the 4 standard cases.

The new release version of riskyr (v0.2.0) includes all these changes.