Introduction

Modula-2 programs are textually separated in so called compilation units which come in three forms:

Module Type	Module Heading	Purpose
program module	MODULE	main module
definition module	DEFINITION MODULE	interface definition
implementation module	IMPLEMENTATION MODULE	implementation of an definition

When successfully processed by the compiler, an object file is generated for program modules and implementation modules, and a so called symbol file for definition modules. Later, if a module is given in an import list or an implementation is being compiled, the associated symbol file is necessary to check module clients and implementors against the interface.

Because of these compilation dependencies it is not convenient to call the compiler ``by hand''. Some Modula-2 compilers provide a built-in environment which supports the compilation in the correct order. Under UNIX, however, a more flexible and open approach is appropiate:

• Makefiles are the standard form under UNIX to express dependencies for building processes.
• Mmm generates and maintains a selected part of your makefiles only. You can easily add dependencies (e.g. for the documentation) to your makefile.