Executable XML users challenge

provide any LISP macro with clear explanation of its structure and function
that is :
1.concise (max 10 lines)
2.does not have a C equivalent(at least not anything above 100 lines)
3.does not use any libraries or imported complex functions which are not in C
If you provide an exact explanation/commentary on what it does i'll try to make a C solution which
is equivalent to LISP one. If i fail to do so, LISP wins, if i provide a solution you can make another macro.
If all examples in the thread are provide with C equivalents, LISP loses.

>>185

It seems that you are giving up. It might not be practical to reverse arbitrary code, but it could be practical to do a similar traversal of the code and locate certain symbols, and do something special to them. Reversing the code is just showing that you can do it. Anything you can do to a list a run time, you can do to your code at compile time. There is no need to resort to FILE IO and recompilation, or scripts and tools to parse your program and generate code which you then link with. Both methods work, but less work and less complexity for the user is involved if it can all be integrated into the compiler by providing one syntactic tool in the language. Just think, what if someone could implement Qt using only ANSI C/C++, and all the QT meta object code generation was created by definitions within the language standard. Using Qt would be as easy to use and provide any other library.