Re: Help - Constructors - ASAP.

[Mats Weber <Mats.Weber@elca-matrix.ch>]

tedennison@my-dejanews.com wrote:

> But what happens in the situation where the client (perhaps a different
> developer) wants to make a child class with fields that *must* be
> initialized? That seems a quite reasonable thing to do. But now the
> class-wide "constructor" isn't valid anymore. It can still be called for this
> new child object, but will return a garbage value.

That garbage value will be a value of the parent type, and assigning it to an
object of the Child type, or to an object of type Child'Class, will raise
Constraint_Error, so the problem will not go undetected. If your contructors
are not class-wide and not primitive, then you detect the problem at compile time.

> The only way I can see around this problem is to *also* declare a primitive
> constructor, and have the body of the class-wide consructor redispatch to
> that.

If you do that, you will run into all sorts of ambiguous call situations where
you will have to qualify your expressions.