Modules BASIC programs consist of one or more modules. A module is a source file that can be separately compiled. A module may contain SUB and FUNCTION procedures, as well as code not directly part of a SUB or FUNCTION. Statements that are not part of a SUB or FUNCTION are called module-level code. Module-level code includes declarative statements like DIM and TYPE as well as error-handling and event-handling code. A program has one special module, the main module. The main module contains the entry point of the program (the place where the program starts running). Each program contains only one main module. In the main module, module-level code corresponds to what is often called the main program.