better algorithm/API for distinguishing mapping vs setting?

[rpruim]

The current algorithm considers anything that is a name of the data to be mapped and all other things to be set. This doesn't allow for on-the-fly calculations like

gf_point(y ~ x, data = Foo, color = y > x)

The culprit is the following code chunk:

data.frame(role = names(res),
                    var = unlist(res),
                    map = unlist(res) %in% data_names)

[rpruim]

I'm giving this a try

res <-
    data_frame(
      role = names(res),
      var = unlist(res),
      map = unlist(res) %in% c(data_names) | role %in% aes_names)

Seems to be working well based on limited testing.

gf_point( zscore(length) ~ zscore(width), data = KidsFeet) %>% 
  gf_smooth(zscore(length) ~ zscore(width), method = "lm") 

[rpruim]

Current wireless network doesn't allow me to push. I'll create a pull request later.