CLEARNOT A B clears all the variables in the calling workspace except A and B (or any variable that is input to CLEARNOT).

Useful for cleaning up a cluttered workspace when you want to preserve a few variables.

The functional form of CLEARNOT is also valid: CLEARNOT('A','B').

TODO: make it work with wildcards.

Example:
a=2;b=3;c=4;d=5;
clearnot a c
This clears B and D but preserves A and C in the workspace.