Mecca (MEmory CAche) is a light, portable, and flexible implementation of a direct-mapped memory cache. Flexibility is achieved by allowing users to hook callbacks for insertion, aliasing, deletion, and comparison events. Locks protect main operations, so it is suitable for use in multi-process or multi-threaded environments.
CL-INTERPOL is a library for Common Lisp which modifies the reader so that you can have interpolation within strings, similar to Perl or Unix Shell scripts. It also provides various ways to insert arbitrary characters into literal strings even if your editor/IDE doesn't support them.