Re: controlled type in generic package?

[John English <je@bton.ac.uk>]

Florian Weimer wrote:
> 
> John English <je@bton.ac.uk> writes:
> 
> > Not only that, but by deriving something from Controlled, you're
> > giving up your ability to derive from anything else. If I want to
> > derive a new type from an existing (non-Controlled) type and add
> > a destructor (Finalize), I have to perform lots of acrobatics and
> > commit all sorts of atrocities on my code to do it!
> 
> It's just an ordinary mixin construction.  Of course, there some
> syntactical overhead involved, but it's straightforward.

Not hard to do, but annoying. A type declaration for the controlled
type, a separate type declaration for the derived type with a controlled
component added in, and if the controlled component's primitives need to
look at any components of the original record, some magic spells involving
access discriminants and view conversions.

This might not bother you, but it feels like acrobatics and atrocities to me.
IMHO this is straightforward in the same sense as OOP in C is straightforward:
"It's just an ordinary pointer-to-array-of-functions construction. Of course,
there's some syntactical overhead involved, but it's straightforward." :-)

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