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.

//void.h 610 bytes
#define STDMAIN int main(int argc,char**argv){;
#define STDEND ;return 0;};
#define cv0p  const void*
#define cs4p const int*
#define is4 inline int
#define sort(array,function)   qsort(array, sizeof(array)/sizeof(array[0]), sizeof(array[0]),function)
#define printints(array) ;for(i=0;i<(sizeof(array)/sizeof(array[0]));i++){printf("%d ",array[i]);};puts("");
#define sortp(array,function)  sort(array,function);printints(array);
#include <stdio.h>
#include <stdlib.h>
is4 cmpn(cv0p num1, cv0p num2){return *(cs4p)num1-*(cs4p)num2;}
is4 cmpr(cv0p num1, cv0p num2){return *(cs4p)num2-*(cs4p)num1;}
//main.c 78 bytes
STDMAIN int i;int arr[]={6,5,8, 1,10,4};sortp(arr,cmpn);sortp(arr,cmpr);STDEND