In a definition file directives lines are lines on which the first character is "#". These allow you to tell the compiler to include a separate text file at this point in the current file. You can "nest" these directives in up to five levels of files. The syntax is:
#include <filename>
... where <filename> is either a full path plus a filename, or just a filename without a path. If no path is given, then the compiler assumes that the file is in the same folder as the top level input file. Examples on a Windows 7 computer:
#include C:\Users\UserProfileName\Documents\Solar Fire User Files\Interpretations\decans.txt
#include decans.txt