Implement detach()

[akbertram]

Attempting to detach a loaded package namespace will display the message

ERROR: Sorry! detach not yet implemented!

and spit out a Java stack trace.

[strboul]

As of the current version (0.9.2725), calling detach() from console seems to work, but it gives a warning. I am not sure if it causes any side effect somewhere else.

> search()
[1] ".GlobalEnv"        "package:stats"     "package:graphics" 
[4] "package:grDevices" "package:utils"     "package:datasets" 
[7] "package:methods"   "package:base"     
> library(hamcrest)
> library(R6)
Loaded org.renjin.cran.R6 version 2.4.0-b1.
> search()
[1] ".GlobalEnv"        "package:R6"        "package:hamcrest" 
[4] "package:stats"     "package:graphics"  "package:grDevices"
[7] "package:utils"     "package:datasets"  "package:methods"  
[10] "package:base"     
> detach("package:R6", unload = TRUE)
Warning message:
'R6' namespace cannot be unloaded:
  could not find function 'unloadNamespace'
> search()
[1] ".GlobalEnv"        "package:hamcrest"  "package:stats"    
[4] "package:graphics"  "package:grDevices" "package:utils"    
[7] "package:datasets"  "package:methods"   "package:base"
> detach
function(name=<missing_arg>, pos=2.0, unload=FALSE, character.only=FALSE, force=FALSE)