Logify is a utility that accepts a class header (.h file) as input and generates a MobileSubstrate extension (.xm file) which hooks all of that class's methods, printing log messages when they are called. This helps a hook developer see when certain methods are invoked during use.
At a bash command line (with Theos installed), run the following command:
logify.pl SomeClassHeader.h > tweak.xm
This will create a new tweak source file (tweak.xm) using the methods defined in the header file `SomeClassHeader.h`. You can then use tweak.xm as the basis for a new tweak project, or integrate the generated code into your own project.