Package Standard is special. It supplies all of the built-in types, and is never withed in. As Barnes says, "... every library unit should be thought of as being declared as a child of Standard." and "It should not be thought that this package necessarily actually exists." [Barnes96]
|This diagram depicts the assumed parent/child relationships between Standard and other library units, for any Ada program. The "actual" predefined units are the three pictured on the right side of the diagram and their many children and grandchildren. (See discussion below.) The application units on the left would have dependency (withing) relationships among themselves, and some of them would depend on units shown on the right (most typically children of Ada, such as Ada.Text_IO or Ada.Calendar).|
Package Ada has 28 public children, and many of
these have children of their own.
(See next page.)
Package System defines various
machine-dependent or configuration-dependent characteristics.
(See page after next.)
Package Interfaces provides facilities
used in mixed-language programming.
(See last page of this appendix.)
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