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.

>>100
it shows that
A.provided C code does what LISP code does
B.LISP code is inefficient, checking each single value type, while constructing a new array for each sort.
C.LISP introduces a leaky abstraction of mixed array, while in reality you can't sort such mixed arrays(its undefined) even in LISP
D.the code in >>39 treats lists as sortable objects.