How can library() accept both quoted and unquoted strings

Question

For example, in an R session, typing library(ggplot2) and library(\"ggplot2\") can both import the library ggplot2. However, if I type ggplot2 in t

Answer 1

This is how (from the source of library(), which is....long):

package <- as.character(substitute(package))

A simple way to test this yourself:

foo <- function(x) as.character(substitute(x))
> foo(a)
[1] "a"
> foo("b")
[1] "b"