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From: Bart Schaefer <schaefer@brasslantern.com>
To: Zsh hackers list <zsh-workers@zsh.org>
Cc: Felipe Contreras <felipe.contreras@gmail.com>
Subject: Re: One possible answer to typeset vs. unset
Date: Thu, 3 Dec 2020 13:19:43 -0800	[thread overview]
Message-ID: <CAH+w=7a0es6W_Si9YbQzszzYBSuubmocot_8goywaL_Owb=pjw@mail.gmail.com> (raw)
In-Reply-To: <CAMP44s2gZnM_JAi78gJwB+uX75Sdx0MQPkW7SZ6tUk85xEjvQg@mail.gmail.com>

On Tue, Dec 1, 2020 at 12:55 AM Felipe Contreras
<felipe.contreras@gmail.com> wrote:
>
> I don't know what would be the proper solution for tied variables, but
> I used this hack to make the tests pass:

I looked at this for a while yesterday evening.  My conclusion is that
tied variables are already a bit of a hack.

It would be nice to be able to determine null-ness (however that ends
up being defined) in bin_typeset where we are actually examining the
"assigns" list of names+values, but the determination of whether a
parameter is being localized or is having its type changed in a
value-preserving compatible way (e.g., typeset -F SECONDS) is down in
typeset_single.  And typeset_single is called twice for tied
variables, always in the same order no matter which of the pair is
being initialized, which is then cleaned up afterward in bin_typeset.
So something convoluted has to be done, especially if both parts of
the pair are supposed to appear "null" when neither is given an
initial value.

Consequently I don't know if your patch would cause a different test
for unset-ness (that hasn't been written yet) to fail, but something
like that patch may be unavoidable.


  reply	other threads:[~2020-12-03 21:20 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-28 19:49 Bart Schaefer
2020-11-28 20:00 ` Bart Schaefer
2020-11-28 20:21 ` Bart Schaefer
2020-12-01  8:54 ` Felipe Contreras
2020-12-03 21:19   ` Bart Schaefer [this message]
2020-12-04 11:04     ` Felipe Contreras
2020-12-04 15:49       ` Bart Schaefer
2020-12-04 19:47         ` Bart Schaefer
2020-12-05  0:22           ` Bart Schaefer
2020-12-05  0:28         ` Bart Schaefer
2020-12-05  0:51       ` Bart Schaefer
2020-12-05 22:17         ` Bart Schaefer
2020-12-23 23:00         ` Felipe Contreras
2020-12-02 17:18 ` Vincent Lefevre
2020-12-02 18:03   ` Bart Schaefer

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