Exuberant Ctags with R

Question

Is there any documented use of ctags with R? Would this be useful? Would it be difficult to implement?

Specifically, I've just started using Vim. It would be cool to be able to write an R function in one file, use the function in another file (e.g., an Rnw file, test file, or some other script), and be able to use Ctrl+] to navigate to the function source.

Update: I've since stumbled on the rtags function. It is suggested below that it works with vim.

Answer 1

This is a modification of Henrico's answer, and may be implemented by copying and pasting the following code into one's ~/.ctags files. Henrico's code did not work for indented functions, but the following code does.

--langdef=R
--langmap=r:.R.r
--regex-R=/^[ \t]*"?([.A-Za-z][.A-Za-z0-9_]*)"?[ \t]*<-[ \t]function/\1/f,Functions/
--regex-R=/^"?([.A-Za-z][.A-Za-z0-9_]*)"?[ \t]*<-[ \t][^f][^u][^n][^c][^t][^i][^o][^n]/\1/g,GlobalVars/ 
--regex-R=/[ \t]"?([.A-Za-z][.A-Za-z0-9_]*)"?[ \t]*<-[ \t][^f][^u][^n][^c][^t][^i][^o][^n]/\1/v,FunctionVariables/

This allows variables to be recognized with ctags as well as functions. If you're using the taglist vim addon, then, it allows you to distinguish between global variables and other variables. Also, if you're using taglist, then you will need to paste the following in your vimrc.

let tlist_r_settings = 'R;f:Functions;g:GlobalVariables;v:FunctionVariables'