* forget

Forget things about symbols. Handy during interactive development.

The ~forget~ function will forget function bindings, symbol bindings,
and class bindings. It will also unintern a symbol from its home package.

The ~forget~ function can forget packages too, but you must pass
~:package? t~ as an argument. 

Any of the default options can be turned off by passing ~nil~ to the
appropriate option. E.g. if you wanted to forget everything but not
unintern the symbol, you'd pass ~:intern? nil~. 

Example:

#+begin_src lisp
CL-USER> (defvar unremarkable "hey")
UNREMARKABLE

CL-USER> (defun unremarkable () "hey")
UNREMARKABLE

CL-USER> (defclass unremarkable () ())
#<STANDARD-CLASS COMMON-LISP-USER::UNREMARKABLE>

CL-USER> (setf (get 'unremarkable :hey) "you")
"you"

CL-USER> (defpackage :unremarkable (:use #:cl))
#<PACKAGE "UNREMARKABLE">

CL-USER> (forget:forget 'unremarkable)
WARNING: Unbinding function UNREMARKABLE
WARNING: Unbinding value UNREMARKABLE
WARNING: Unbinding class UNREMARKABLE
WARNING: Dropping symbol-plist on UNREMARKABLE
WARNING: Uninterning UNREMARKABLE from "COMMON-LISP-USER"
NIL

CL-USER> (forget:forget 'unremarkable :package? t)
WARNING: Uninterning UNREMARKABLE from "COMMON-LISP-USER"
WARNING: Deleting package "UNREMARKABLE"
T
CL-USER> 

#+end_src