Re: Ada terminology (was Re: Real OO)

[cjames3@concentric.net (The Right Reverend Colin James III)]

Remove comp.lang.eiffel from distribution of this thread.

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lady0065@sable.ox.ac.uk (David Hopwood) posted with deletions:

| In article <4mls4h$sau@watnews1.watson.ibm.com>,
| Norman H. Cohen <ncohen@watson.ibm.com> wrote:
| >
| >In Ada, a class is not a type, but a SET OF TYPES.  In particular, the
| >set of tagged types directly or indirectly derived from a common root
| >forms a "derivation class".  ("Deriving" from a type means defining a
| >descendant type.)  For each type T at the root of a tree or
| >subtree in the derivation hierarchy, there is a "classwide type",
| >T'Class, whose values are taken from the discriminated union of the types
| >in the class.  One cannot derive from a classwide type.
| >(By "discriminated union," we mean that for each value V of each type in
| >the class, there is a corresponding value in T'Class, and that the
| >corresponding value in T'Class includes a "tag" identifying the type of
| >the original value V.)
| 
| Maybe it's just me, but...
| Why does Ada use the words 'type' and 'class' in the opposite sense
| to everyone else?
| 
| David Hopwood
| david.hopwood@lmh.ox.ac.uk


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