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Ada '83 Rationale, Sec 9.4: Summary and Conclusion

"Rationale for the Design of the
Ada® Programming Language"

[Ada '83 Rationale, HTML Version]

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CHAPTER 9: Packages

9.4 Summary and Conclusion

A simple approach was taken for the package facility of Ada. Packages provide the ability to encapsulate information. When defining a package, the programmer simply states the visible information and provides its implementation as a separate text - the package body. The information contained in a package body is not (directly) available outside the package body. Thus, packages support information hiding as well as control of visibility.

The package facility is central to the definition of private data types: it provides complete control over the available operations for such types. Moreover, packages can be separately compiled and the language also provides a parameterized form of package, called a generic package.

All of these aspects are in many respects fundamental for program development. Packages are used to construct libraries containing common pools of data and types, application packages, and complete systems.

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