SAS Programs and Macro Processing
This section describes the typical pattern that SAS follows to process a program. These concepts are helpful for understanding how the macro processor works with other parts of SAS. However, they are not required for most macro programming. They are provided so that you can understand what is going on behind the scenes.
Note: The concepts in this section present a logical representation, not a detailed physical representation, of how SAS software works.
When you submit a program, it goes to an area of memory called the input stack ...