On 30 Jun, Bart Schaefer wrote:

> We should emulate ksh when `name' is already a nameref.
> However, we could follow our usual pattern of choosing some other syntax
> that's illegal in sh/ksh and giving it additional semantics; e.g.

Okay, that sounds good though I'll get the basics working first before
any new for syntax.

> > > } what should ${(t)ref} return - the same as what it refers to with
> > > } -nameref- inserted?

> Hmm, that's probably true.  In which case I'm not even sure if it should
> insert -nameref- anywhere.  Hard to say.

I know what you mean. My thinking behind inserting -nameref- was that
it would enable shell code to detect namerefs -- so for example I can
write a proper completion for unset -n -- while being compatible with
any old shell code that pattern matches against the output of ${(t)ref}
(which most probably does).

> > In 5068, you said that ksh has "separate namespaces for namerefs and
> > parameters". Can you remember what you meant by that?
> 
> Exactly what you mentioned before -- `nameref ref=var; typeset ref'
> doesn't output anything, and `unset ref' doesn't remove `ref', so the
> name `ref' does not behave like a parameter name.  What I didn't realize
> at the time was that `unset ref' actually removes `var', nor that there

The name `ref' does behave like a parameter name in ksh. `typeset ref' is just
defining ref if it isn't already defined so it will never output anything for
any variable in ksh. You have to do `typeset|grep ref'.

> was such a thing as `unset -n'.  (Flags to `unset'?  Heresy!)

Well, we already have two flags to unset -- -f and -m (and I've just realised
that I've not done a completion for them).

Anyway, I had a little time on the weekend to look at using a pointer for the
nameref. I am convinced that it is the better way, it'll just be slightly less
easy because I have to meddle more with existing code. The first problem is that
fetchvalue() currently returns NULL for PM_UNSET variables which I'm probably
going to have to change.

In case anyone is interested, attached is a descripton of ksh93 features which
aren't in zsh. Let me know if you know of things to add to it.

Oliver