Can't use @ or ` in the Roxygen documentation strings

[garyfeng]

I can't figure out how to escape these 2 characters in the #' section. These are critical.

• @ is the name of the function I want to export. I am using %AT% as a temporary replacement, but it makes the documentation confusing
• one way of calling the @ function is to do ``@(list, key). But ` seems to be a special char in Rd. Roxygen doesn't complain, but I get the following error when I try to show the help file.

> devtools::document(pkg="/Users/garyfeng/github/local/dfat")
Updating dfat documentation
Loading dfat
Writing grapes-at-at-grapes.Rd
Writing at.Rd
> ?"@"
Error in tools::parse_Rd(path) : 
  Unexpected end of input (in ` quoted string opened at grapes-at-at-grapes.Rd:38:8)
In addition: Warning message:
In tools::parse_Rd(path) :
  newline within quoted string at grapes-at-at-grapes.Rd:38