The tidyselect package is the backend of functions like dplyr::select() or dplyr::pull() as well as several tidyr verbs. It allows you to create selecting verbs that are consistent with other tidyverse packages.
To learn about the selection syntax as a user of dplyr or tidyr, read the user-friendly Selection language reference.
To learn how to implement tidyselect in your own functions, read the Get started vignette.
To learn exactly how the tidyselect syntax is interpreted, read the Technical descrition vignette.
tidyselect is on CRAN. You can also install the development version from github with: