Macro

     (expression) In CA-Clipper, an operation that allows source code to be
     compiled and executed at runtime.  In CA-Clipper, the macro symbol (&)
     does not perform text substitution unless embedded within a character
     string.  Instead, it is generally treated as a unary operator that
     operates on a character string.  The text in the character string is
     compiled on the fly using a special runtime compiler.  The resulting
     code is then executed, and the value obtained is returned as the result
     of the macro operation.