Yes, macros can make code very hard to read, if designed badly. Of course, so can functions, variable names, and program flow. But Lisp with macros is very dif

Yes, macros can make code very hard to read, if designed badly. Of course, so can functions, variable names, and program flow. But Lisp with macros is very different from C++ with operator overloading. With C++ operator overloading, you only know if a given line has something you don't understand (that is, an overloaded operator) by looking at every other file in your project. With Lisp macros, you know that you're dealing with something new because you don't recognize the first token in the s-expression. You might not know it's a _macro_ rather than just a _function_, but you know it's something you need to investigate. Basically, in Rumsfeld's terminology, an overloaded operator is an unknown unknown, but a Lisp macro is a known unknown. A macro's behavior may be confusing, but its existence isn't. And that's a very big difference.