On Monday, July 22, 2013 11:08:35 AM Irek Szczesniak wrote:
> On Mon, Jul 22, 2013 at 11:00 AM, Dan Douglas <[email protected]> wrote:
> > In this type, I can't think of any way to refer to "obj" from within
> > "x.get".
> > _ should point to "obj" in this context, not "obj.x".
> >
> > #!/usr/bin/env ksh
> >
> > typeset -T Type=(
> > typeset -h 'This will be a property.' x
> > integer -h 'This will be the backing field for x.' y=5
> >
> > function x.get {
> > # Huge problem here because _ refers to x,
> > # we can't access anything.
> > ((.sh.value = ++_.y))
>
> This can't work. .sh.value is identical to _
>
> Think about ksh93 types as compound variables with predefined
> discipline functions. In your example you're trying to assign the
> value of ++_.y to the value of a compound variable - which obviously
> cannot work.
>
> Irek
I don't know, it doesn't make sense to me for disciplines within types that
hook the fields of the type. I think _ should be different here than for a
bare discipline defined in the global scope. Those don't have to care about
which instance they are a part of.
The only workarounds I can think of are nasty, like:
nameref this=${.sh.name%.*}; .sh.value=${this.y};
--
Dan Douglas
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