MAD-X consists of a core program, and modules for specific tasks such as twiss parameter calculation, matching, thin lens tracking, and so on.
The statements listed here are those executed by the program core. They deal with the I/O, element and sequence declaration, sequence manipulation, statement flow control (e.g. IF, WHILE), MACRO declaration, saving sequences onto files in MAD-X or MAD-8 format, and so on.