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From: "Bart Schaefer" <schaefer@brasslantern.com>
To: "Johan Sundström" <johsu650@student.liu.se>,
	Zsh-list <zsh-users@math.gatech.edu>
Subject: Re: Static variables?
Date: Sat, 13 Jun 1998 23:38:27 -0700	[thread overview]
Message-ID: <980613233827.ZM30068@candle.brasslantern.com> (raw)
In-Reply-To: <002801bd9750$a021f600$cde8ec82@a205.ryd.student.liu.se>

On Jun 14,  6:55am, =?iso-8859-1?Q?Johan_Sundstr=F6m?= wrote:
} Subject: Static variables?
}
} Is it possible to use c-style "static" variables in my functions, or do I
} have to stick to global ones?

The only "persistent" variable namespace is the global one.

That said, there may be a way to get the effect you want, because the
"local" namespace has dynamic scope.  Here's how:

First, rename your precmd as precmd_body.

Next, create a function precmd_setup which assigns values to the variables
you wish to make static.

Now create a new precmd which does the following:
- Declares "local" all the variables that are assigned in precmd_setup
- Executes precmd_setup (this assigns to the locals of precmd)
- Executes precmd_body (this references the locals of precmd)
- Redefines precmd_setup to assign the new values of the locals to
  the appropriate names, e.g. eval function precmd_setup \{ ... \}

Finally, be sure that none of the affected variables is declared local
in precmd_body (so it will inherit the locals from precmd).

The tricky bit is "redefines precmd_setup."  Depending on the values of
the variables in question, it may be difficult to generate on the fly a
new definition that performs the correct assignments.  Just how ugly are
the contents of the variables you're trying to preserve?

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com


      reply	other threads:[~1998-06-14  6:42 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1998-06-14  4:55 Johan Sundström
1998-06-14  6:38 ` Bart Schaefer [this message]

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