From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <zsh-users-return-20870-mason-zsh=primenet.com.au@zsh.org>
Received: (qmail 26646 invoked by alias); 2 Nov 2015 03:08:50 -0000
Mailing-List: contact zsh-users-help@zsh.org; run by ezmlm
Precedence: bulk
X-No-Archive: yes
List-Id: Zsh Users List <zsh-users.zsh.org>
List-Post: <mailto:zsh-users@zsh.org>
List-Help: <mailto:zsh-users-help@zsh.org>
X-Seq: 20870
Received: (qmail 25833 invoked from network); 2 Nov 2015 03:08:47 -0000
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on f.primenet.com.au
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,T_DKIM_INVALID
	autolearn=ham autolearn_force=no version=3.4.0
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=brasslantern_com.20150623.gappssmtp.com; s=20150623;
        h=from:message-id:date:in-reply-to:comments:references:to:subject
         :mime-version:content-type;
        bh=VTX+4MB39uUGXL1TRIaZxz2vRWgxmZnA9mzEYCIZtSE=;
        b=cBNnUC28ViO0lnhCHwSkujkx6oJZEfUw0GAWbtN9Cv7YSN6doVNd+OEnR0qosTSxlC
         riFy2wWdHbYmzknvGKQwMBf9ncVDqfNbfXQDNu2OtJwalz/8NjYXUblKv42Jg9jr07Du
         Zl/3CynPh/d21VTn0Fv+Cy0qhCRQNUxELbP+/z9BZL5iaqSgTHVmkqSnFr5Qd05t05vQ
         ZsjawqDlYefbXdXRqj7S5rTe5Xbye/Ih0nvJ9114Av9PfiGpYyz11tqQLoETGxgGDPJq
         GhmqxJ0JrP4SFcsb552Sut8yZSAKgiwiFD80bNXf4EJ29sIOu1BOIZmCeBiF0PJOA97D
         MmBQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=1e100.net; s=20130820;
        h=x-gm-message-state:from:message-id:date:in-reply-to:comments
         :references:to:subject:mime-version:content-type;
        bh=VTX+4MB39uUGXL1TRIaZxz2vRWgxmZnA9mzEYCIZtSE=;
        b=MgHundI5fLiJBMtWDRpCs7KaANdT3NmFOj6XRi1/tu6LKsOSIlonl2etbFHgqa4NQC
         vbIyZO+2Vyjm5YgUgYnS1a34knLnAeg0ERnUSGX3cJYux2Ii7LEFuVayqLpi80rheHJv
         8p9Ej9J9r5lHEDto32fxLMEn6uUwv4RwOl+t8O9pzrZpEsepItCKrmcNQeS4kyTZiWkp
         eRGvnk8wNFr46ti/Lj/HFJ3q6mARUBxeHfwSVPl38RP74O5AKPK+ouCcQ8RmP4BFHN5Z
         tIQ/InHrywAEbr5/fiq81KZJLO46N2MZYxbioSmtFeW06I5qvaseLM39YzBvX4UZGfsx
         ykkA==
X-Gm-Message-State: ALoCoQkPo7+sKz0OmpKzxwzCHt3WhZIVtZunzg2a5mkJ0hKJ8hgJf0WUYAgW1kCSNK/iRLPk3joO
X-Received: by 10.202.199.142 with SMTP id x136mr12411099oif.121.1446433724962;
        Sun, 01 Nov 2015 19:08:44 -0800 (PST)
From: Bart Schaefer <schaefer@brasslantern.com>
Message-Id: <151101190842.ZM16752@torch.brasslantern.com>
Date: Sun, 1 Nov 2015 19:08:42 -0800
In-Reply-To: <5636B333.8060300@eastlink.ca>
Comments: In reply to Ray Andrews <rayandrews@eastlink.ca>
        "Re: easy calling of associative array?" (Nov  1,  4:49pm)
References: <56369C7B.2030604@eastlink.ca>  <1237641446422150@web6m.yandex.ru> 
	<5636B333.8060300@eastlink.ca>
X-Mailer: OpenZMail Classic (0.9.2 24April2005)
To: zsh-users@zsh.org
Subject: Re: easy calling of associative array?
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii

On Nov 1,  4:49pm, Ray Andrews wrote:
} Subject: Re: easy calling of associative array?
}
} On 11/01/2015 03:55 PM, ZyX wrote:
} >
} > There is ${(P)} for indirect referencing:
}
} I can't get it to work with associative arrays tho.

Yeah, it's a bit weird with associative arrays because everything is
passed by value.  ${(P)ref} is ${(vP)ref} and thus ${${(P)ref}[idx]}
doesn't get what you want, and ${(P)ref[idx]} is ${(P)${ref[idx]}}
which also isn't what you want.

So you have to get a little arcane:  ${(P)${:-${ref}[idx]}}.

- ${ref} is the name of the assocative array.

- ${ref}[idx] is therefore a string that has the same format as the
  array lookup you want to perform.

- ${:-${ref}[idx]} substitutes that string into a parameter expansion.

- ${(P)${:-${ref}[idx]}} then treats that substitution as another
  parameter expansion, and you end up where you wanted to be.

This is admittedly not ideal, but until we embark on a significant
rewrite of parameter expansion, we're stuck maneuvering values into
the right places at the right times.