Declaring Global Variables and Named Constants

CLtL2 Reference 

macro DEFVAR : (variable &optional initialization documentation)

macro DEFPARAMETER : (variable initialization &optional documentation)

DEFVAR and DEFPARAMETER are the SubL constructs used to define global variables. The name of each variable must begin and end with an asterisk.

SubL enforces an important distinction between these two constructs, which is described in greater detail under WRITE-IMAGE.

macro DEFCONSTANT : (variable initialization &optional documentation)

As with DEFVAR and DEFPARAMETER, the name of each named constant defined via DEFCONSTANT must begin and end with an asterisk.