A system is defined with a
form in an ordinary Lisp source file. This form must be evaluated in the Lisp image in order to use the system.
Once defined, operations can be carried out on the system by invoking Lisp functions.
For example, the expression:
CL-USER 5 > (compile-system 'debug-app :force t)
would compile every file in a system called
Note: When defining a hierarchy of systems, the leaf systems must be defined first--that is, a system must be defined before any systems that include it.
By convention, system definitions are placed in a file called
which usually resides in the same directory as the members of the system.