while bringing some functions from tidyr to dbplyr I noticed that a couple of tidyr functions should probably be generic:

• uncount()

the pivot helpers would make sense as the dbplyr implemention of pivot_*() uses them anyway

• build_longer_spec()/build_wider_spec()
• pivot_longer_spec()/pivot_wider_spec()

data frame column helpers would make sense as nested tables in SQL are becoming more common (e.g. see tidyverse/dbplyr#515)

• pack()/unpack()
• unnest_longer()/unnest_wider()

list column helpers: not sure if they are needed but for completeness I also listed them here:

• chop()/unchop()
• hoist()