> the maintainer in me started to think about what it would be like to debug that That's a valid question. Lisp macros open up a new dimension programming and

> the maintainer in me started to think about what it would be like to debug that That's a valid question. Lisp macros open up a new dimension programming and now we have the problem to debug/maintain code with macros. The SETF machinery in one way tries to simplify code (the code then has one style of assignments, not different ways and one does not need to know a special accessor - just wrap a form which looks like it GETs the value and Lisp will figure out how to SET the value). OTOH the SETF machinery is non-trivial. It's usually quite usable, but some of the details are complex - especially since it is user-extensible. It's definitely something to look for: programmers in a Lisp project might need some extra education when it comes to macro programming, to make sure, that they have a good understanding of the basic mechanisms. Also it always makes sense in a team to have more than one person looking at a macro implementation.