Oh god, this way lies madness. :) It really does. Once you get beyond a fairly low level of complexity, there will be maintainence problems: It will take you too long to get it right, it will be impossible to figure out when something goes wrong, and you'll drive the next poor developer crazy if he doesn't have a complete knowlege of make (which is most of us). Yes, sometimes it may be neccesary to do this if you want to reuse some rules and functions but modify them under different conditions, AND you are restricted to doing it all in the Makefile (rather than preprocessing, calling out to external scripts, etc.)