safe

http://www.purl.org/tcl/home/man/tcl8.4/TclCmd/safe.htm

Safe Base - A mechanism for creating and manipulating safe interpreters.

Bob Techentin asked questions on comp.lang.tcl regarding the use of safe interpreters running code that uses the [package require] mechanism. The Safe Base supports some package loading, but is mentioned less often than [interp create -safe]

Bob Asked:

: How, in your opinion, Jacob, does [::safe::interpCreate] jibe with [interp create -safe]? Am I foolish for wanting to grant something beyond core functionality to a safe interpreter? If so, what is the real point of the Safe Base mechanism?

and Jacob Levy replied

: The answer is that nilly willy you're going to want to source some stuff into a safe interpreter, open some scratch files etc. So, either you come up with your own idiosyncratic solution, or use safe::interpCreate to do it in a semi standard way.
: In other words, [interp create -safe] gives you a raw interpreter without any aliases. That's of course also what safe::interpCreate does internally. And then it adds some aliases that were very very carefully designed to be safe (nearly as safe as the base safe interpreter that [interp create -safe] returns. The Safe Base is therefore simply one way to extend the raw safe interpreter, and has been carefully reviewed and used extensively, so it's believed to be safe.
: If you were to roll your own, you could easily introduce some of the bugs that the war tested Safe Base has already avoided.