CODEWITHSUNDEEP
adaderived-typessubtyping
Martel
Martel

Reputation: 2744

Is assignment the only difference between derived types and subtypes in Ada?

I have read that derived types are completely different types than their respective parents, however the do inherit all their parents' operations.

In other words, you can pass a derived type A to a operation that receives as a parameter a type B which is A's parent. However, you can't assign a variable of type A to one of type B and vice versa.

According to the above, the only difference between derived types and subtypes is the assignment. Is that right?

Upvotes: 0

Views: 205

Answers (1)

Jacob Sparre Andersen
Jacob Sparre Andersen

Reputation: 6611

Derived types only inherit the primitive operations of the type they are derived from.

Technically the type derivation creates a new set of primitive operations, so you can't "pass a derived type A to a operation that receives as a parameter a type B which is A's parent". But the compiler creates operations of the same name and implementation, which work on type A from the primitive operations of type B. You can for example remove the inherited operations by explicitly declaring them abstract.

Upvotes: 4

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