




 
A system is defined with a 
defsystem
 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.
CL-USER 5 > (compile-system 'debug-app :force t)
would compile every file in a system called 
debug-app
.
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 
defsys.lisp
 which usually resides in the same directory as the members of the system.
LispWorks IDE User Guide (Macintosh version) - 25 Nov 2011