ada Parameterized Types Variant Record Structures
Example
A discriminant of a record type may influence the structure of objects. A choice of components may exists in an object according as a discriminant had had a particular value when the object was created. To support this variation, a record type's definition includes a distinction by cases that depends on the discriminant:
type Fruit is (Banana, Orange, Pear);
type Basket (Kind : Fruit) is
record
case Kind is
when Banana =>
Bunch_Size : Positive;
Bunches_Per_Box : Natural;
when Pear | Orange =>
Fruits_Per_Box : Natural;
end case;
end record;
Then to create a box for bananas,
Box : Basket (Banana);
The Box object now has two record components in addition to its discriminant, Kind, namely Bunch_Size and Bunches_Per_Box.
