Thank you, flamerz, but I am aware of it. After reading that blog, I actually wondered whether EmEditor can be a “complete front end of R” like Vim-R-plugin (http://www.r-bloggers.com/r-with-vim/). The script you refer to allows to (i) invoke R (ii) and then process the whole command.
What I wish to be able to do is to send (i) a line or (ii) selected lines of commands from within EmEditor without having to invoke R every time I do that.