🚀 go-pugleaf

How do polymorphism and multiple inheritance interact?  If a class, C,
inherits from two others, A and B, can a reference of type C be
assigned to one of type A or B?

I can't see any problem offhand.  I would think such an assignment
would be prohibited with repeated inheritance.


class A
    ...
end;


class B
    ...
end;

class C
    inherit A; B
    ...
end;

class main
feature
    c:C;
    b:B;
    a:A;
...
    a := c;     <--- Is this legal?
    b := c;     <--- Is this legal?

end;

OOSC indicates a polymorphic assignment is legal if the type being
assigned conforms to the type being assigned to. This rule is defined
in the book before multiple inheritance is introduced.  I couldn't
find a better definition for conformance involving multiple
inheritance.  Do you know?

(Our disk where news is stored had some problems recently.  So you may
have seen this message before.  But I was unable to receive any
responses.)

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Chris Hind Genly, N1GLZ - Multiflow Computer - mfci!genly (203)488-6090