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Re: Treatment of illegal indices

X-seq: zsh-workers 3782
From: Peter Stephenson <pws@xxxxxx>
To: Bernd Eggink <eggink@xxxxxxxxxxxxxxxxxx>, zsh-workers@xxxxxxxxxxxxxxx (Zsh hackers list)
Subject: Re: Treatment of illegal indices
Date: Mon, 23 Feb 1998 10:23:21 +0100
In-reply-to: "Bernd Eggink"'s message of "Sun, 22 Feb 1998 16:07:40 MET." <34F03F3C.5FFA09E@xxxxxxxxxxxxxxxxxx>

Bernd Eggink wrote:
> The way zsh treats illegal array indices is pretty ugly. It simply
> replaces indices which are 0 (with KSH_ARRAYS unset) or < -length by 1.
>
> Possible improvements could be:
> 
> c) Print an error message if an illegal index is used on the left      
> side of an assignment, return an empty value otherwise.

I think this is better; it's fairly standard for interpreted languages.
The `feature' that 0 is treated as 1 has been around for a long time,
but since KSH_ARRAYS it's probably time it went.  You are supposed to
be able to extend arrays by assignment, remember:  some time ago there
was an argument about whether

23456789=''

using up a lot of memory was a bug, and it was decided it wasn't.

-- 
Peter Stephenson <pws@xxxxxx>       Tel: +39 50 911239
WWW:  http://www.ifh.de/~pws/
Gruppo Teorico, Dipartimento di Fisica
Piazza Torricelli 2, 56100 Pisa, Italy

References:
- Treatment of illegal indices
  - From: Bernd Eggink

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