How safe is $SAFE=4? I read the description of $SAFE in “Programming
Ruby: The Pragmatic Programmer’s Guide” and it sounds like $SAFE is
specifically designed for running code from untrusted sources.
So, if I put a form on a website that executes whatever code people
put into it with $SAFE=4, would this be safe? (Is there a good webpage
that talks about the use of $SAFE further?)