# Section 8.0:
Introduction

Each section of the library has its own index to the individual class specifications. Most of the individual specifications indexed refer to a single class. A few, however, are overloaded having different numbers of class arguments. In these cases a single specification page covers the definition of both (or all) of those classes with the same name.

The classes defined in this section of the definition are required of a conforming implementation. This does not mean, however, that the actual classes provided by an implementation will have only those features specified here.

For example, a program manipulating culture components will probably need some 'writing' feature corresponding to a 'reading' feature required in this section of the definition. It would be wasteful of effort to have a completely separate class for such a purpose. An implementation is permitted to take any appropriate course while not altering the semantics of a named class specified in this section.

Where an implementation needs additional classes or partial classes in order to implement the specified functionality then it is free to do so with (or without) documenting such additional classes for the user.

Reading a specification

Each feature of a class is defined in three parts -

- The Sather signature for the feature.
- An implicit vdm specification giving pre and post conditions.
- A descriptive specification in English which is intended to have the same meaning as the vdm.

Each class name in the specification will be linked to the specification of that class except for class arguments, the class being defined and the pervasive identifier SAME.

Examples

Where appropriate a feature in an implementation class will have a link to an example of use of the feature, together with an explanation of the example code.

Every use of a feature name in such example code will be linked to the feature definition. Every class name will be linked to the class specification as for definitions themselves.

NOTEWhere this documentation is being read by a browser then it is intended that a user reading specification then example will make use of previous/next page facilities to switch between the two as needed.

| Language Index |  | Library Index

Comments or enquiries should be made to Keith Hopper . Page last modified: Friday, 10 March 2000. |