6.8.2 Making sure that symbols are kept

Internal symbols in packages you have kept may still be shaken out. If any such symbol must be kept in the application, it can be retained by force in the following three ways:

1. With the :keep-symbols keyword.

This is the recommended solution. See :keep-symbols (page :keep-symbols).

2. Export the symbol from the package.

External symbols are always shaken during delivery.

You can override this behavior by passing :shake-externals nil to deliver . See :shake-externals (page :shake-externals). You can also specify :packages-to-shake-externals and :packages-to-keep-externals , pages :packages-to-keep-externals and :packages-to-shake-externals.

3. Make explicit reference to the symbol with another object that you know will not be deleted.

A reference from the object to the symbol ensures that the garbage collector passes over it during delivery.

See also Coping with INTERN and FIND-SYMBOL at runtime.