Syntax for temporary grouping

[hadley]

Syntax ideas:

df %>% with_groups(mutate, this, that)(foo = 1)

df %>% with_groups(c(this, that), mutate, foo = 1)

[romainfrancois]

I think I prefer the second one. I suppose we could make it compatible to this as well:

df %>% with_groups(c(this, that), ~ mutate(., foo = 1))

[hadley]

Ah yes, nice! And that actual solves a tidy-eval challenge I was having