The conditional expansion facility of a macro processor is provided to expand certain model statements depending upon the value of a condition during the process of macro expansion.
This facility allows the macro processor to make decisions based on conditions and selectively include or exclude certain parts of the macro definition during the expansion process. It provides a way to customize the behavior of the macro expansion based on conditions specified in the source code or through parameters passed to the macro. This feature enhances the flexibility and adaptability of the macro processing mechanism.