R - "Browser()" on Error?

Question

I have been using some R libraries to analyze some large data recently, and I find myself frustrated by waiting several hours for the beginning of an analysis, just to get to the end and receive some trivial error, like that I did not install a prerequisite library, or that one of my parameters was wrong. So, then I have to start all over, do the exact same analysis, generate the same variables that it had when it died, and wait a long time. Please note that these are not handled exceptions--they are fatal errors from R.

This is just a thought--and perhaps it is too good to be true, so please at least explain why it wouldn't work--but is there any way to cause R to execute "browser()" in the environment whenever it has a fatal error? For example, say it is executing a script, and encounters "require(notInstalledYet)". Instead of just dying, and losing all the variables in the memory, it would be great if it would give me a browser() at the place it died, so that I could at least save the variables, and at best, fix the problem (e.g. install the library) and try again.

Answer 1

You can change the error option to open a browser on error

options(error=browser)

the default is

options(error=NULL)