Chapter 4  Introduction

4.1  Program structure

1. At the top-most level, a Moby program is structured as a collection of source groups. A source group may be specific to a given application or it may be a library that can be reused by many applications.
2. A source group consists of a set of Moby compilation units. A Moby compilation unit is either a signature, a module, or a parameterized module. Associated with each compilation unit is a prelude that describes various aspects about the compilation context used to compile the unit.
3. A signature consists of a sequence of specifications.
4. A module or parameterized module has a body that consists of a sequence of declarations.
5. Declarations.
6. Expressions.
7. At the lowest level is Moby's lexical structure, which is covered in Chapter 5.

4.2  Notation