get filename and path of `source`d file

Question

How can a sourced or Sweaved file find out its own path?

Background:

I work a lot with .R scripts or .Rnw files. My projects are o

Answer 1

I have no direct solution how to obtain the directory of the file itself but if you have a limited range of directories and directory structures you can probably use

 if(file.exists("c:/somedir")==TRUE){setwd("c:/somedir")}

You could check out the pattern of the directory in question and then set the dir. Does this help you?