e.g. dynamic `FLET` and method bindings with `PROGM` may be of general
interest.
+
+# UTILITIES
+
+`DFLET` dynamically rebinds functions similar to `FLET`:
+
+ > (defun foo () 42)
+ > (defun bar () (foo))
+ > (bar)
+ > => 42
+ > (dflet ((foo () 23))
+ > (bar))
+ > => 23
+ > (OR) => 42, if FOO was inlined
+
+The caveat is that this might not work on certain optimization settings.
+
+The underlying function `PROGF` may be used as well similarly to standard
+`PROG`:
+
+ > (progf '(foo) (list (lambda () 23))
+ > (bar))
+ > => 23
+ > (OR) => 42, if FOO was inlined
+
[1]: http://common-lisp.net/project/closer/closer-mop.html