[plt-scheme] class.ss positional initialization of inherited fields

From: Matthew Flatt (mflatt at cs.utah.edu)
Date: Mon Nov 11 11:49:13 EST 2002

At Fri, 1 Nov 2002 13:11:19 -0500, "Neil W. Van Dyke" wrote:
> Is there a way with PLT 200 "class.ss" to inherit initialization fields
> from a superclass, such that they can be used within methods, *and* have
> the inherited fields come first in the make-object positional
> initialization order?

I've just committed a change to `class' that allows separate internal
and external names for fields and init arguments (finally!).

So, now the order you want is possible with

     (define a% (class* object% ()
                  (init-field        x)
                  (super-instantiate ())))
     (define b% (class* a% ()
                  (init              x)
                  (init-field        y z)
                  (inherit-field     (orig-x x))
                  (define/public     (xyz) (list orig-x y z))
                  (super-instantiate () [x x])))

Note that this technique requires repeating the init arguments in b%
that you want to be in front for the init-argument order, and then
passing on the arguments explicitly in `super-instantiate'. We don't
have anythong more automatic right now.


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