From: "Bart Schaefer" <schaefer@brasslantern.com>
To: zsh-workers@sunsite.auc.dk
Subject: ${(P)${foo}} (Re: Associative array ordering)
Date: Tue, 2 Feb 1999 09:41:24 -0800 [thread overview]
Message-ID: <990202094124.ZM6976@candle.brasslantern.com> (raw)
In-Reply-To: <199902021658.RAA09882@beta.informatik.hu-berlin.de>
On Feb 2, 5:58pm, Sven Wischnowsky wrote:
} Subject: Re: Associative array ordering and selective unset (Re: Example
}
} I wrote:
}
} > Maybe yet another flag? E.g.: `P' makes the thing after the
} > flags be used as the name of a parameter. So `${(P)foo}' is the same
} > as `$foo', but `${(P)${foo}}' will take the value of `foo' as the name
} > of a parameter and work on it.
}
} The patch below does this (it was quite easy).
Well, you got to that before I got around to responding to that particular
tidbit.
The other day someone asked about ksh namerefs in zsh, and I said that with
${(e)...} you didn't really need them. Here's a case where they would have
been exactly what the doctor ordered; in an appropriate muddle of ksh and
zsh syntax,
nameref ref=$arg[1]
echo ${(t)!ref}
which is a whole lot easier on the eyes, it must be admitted.
} With it you can do
} things like the above or `${(P)+${foo}}' to see if the parameter whose
} name is stored in `foo' is set.
There are actually several ways we can go from here.
We can keep Sven's syntax as is.
We can modify Sven's syntax so that ${(P)foo} is the same as ${(P)${foo}},
and make ${!foo} a synonym for it in ksh compatibility mode. This is
almost like ksh namerefs except that they don't get their own namespace.
We can make ${!foo} a synonym for ${(P)${foo}} (either in ksh mode or all
the time), leaving ${(P)foo} alone. I'm not too thrilled about this one.
We can add another hash table to be the nameref namespace, implement the
nameref and `typeset -n' builtins, and make ${(P)foo} [or another letter]
and ${!foo} synonyms where `foo' must be a nameref. That would deprecate
${(P)${foo}}.
--
Bart Schaefer Brass Lantern Enterprises
http://www.well.com/user/barts http://www.brasslantern.com
next prev parent reply other threads:[~1999-02-02 17:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-02-02 16:58 Associative array ordering and selective unset (Re: Example function) Sven Wischnowsky
1999-02-02 17:41 ` Bart Schaefer [this message]
1999-02-03 8:02 ${(P)${foo}} (Re: Associative array ordering) Sven Wischnowsky
1999-02-03 8:39 ` Bart Schaefer
1999-02-03 9:55 Sven Wischnowsky
1999-02-03 10:06 Sven Wischnowsky
1999-02-03 10:42 ` Peter Stephenson
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