text: 
  #ifndef MACROFUN_BLANK_H
  #define MACROFUN_BLANK_H
  
  
  // Preprocessor recursion can occur between two different macros; a macro
  // can't recurse directly into itself, but it can call another macro that
  // calls the first again. This value should be used to separate the name of
  // the paired macro, and its argument list; see `map.h` as an example.
  #define BLANK
  
  
  #endif // ifndef MACROFUN_BLANK_H
  
  