unload/rollback question

[Peter Tury]

Hi,

is it possible anyhow to "unload" something what was previously loaded by
load or require? E.g. a mode? Without restarting Emacs. It just came to my
mind how would it be possible to test some mode under development: when I
think I could try something I would like to start from a "clean page", so
unloading safely everything what was tried previoulsy would be a must.

Does unload-feature do this? It seems for me that it works only if it is
"supported" by that mode... (Is unload-feature a new stuff? Since then old
modes immediately are out of scope...:-(

Could undo be used somehow?

Would this be possible with a little help to Emacs? E.g. evaluating some
insert-savepoint-now and later a rollback-to-savepoint (like in (Oracle)
SQL)?

Thanks,
P