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Re: comment on RFE: 'shift'' [N] ARRAYNAME

From: L A Walsh
Subject: Re: comment on RFE: 'shift'' [N] ARRAYNAME
Date: Thu, 27 Sep 2018 10:56:45 -0700
User-agent: Thunderbird

On 9/27/2018 5:35 AM, Greg Wooledge wrote:
On Tue, Sep 25, 2018 at 05:17:27PM -0700, L A Walsh wrote:
It struck me as it might be convenient if 'shift' could take an optional
arrayname as an argument.  Would that be possible or would it cause some

The biggest issue here is how you specify the arguments.

Shift already takes one optional argument: the number of items to shift
from the argv list.  Adding a second optional argument leads to a quagmire.
Do you put the optional list name first, or do you put the optional number
first?  If only one argument is given, is it a list name, or is it a number?

(OK, granted, in bash it is not permitted to create an array whose name
is strictly digits, but still.)

If you wish to write an array-shifting builtin, it would be better to give
it a new name.  Don't blindly copy perl.  It's not always the best example
of language design.
   Why do you think I was blindly copying perl.  My function example
was/is named lshift to differentiate it from rshift (if wanted),
but if it was a builtin there'd be no need for a different
name as it works and has compatible syntax with current 'shift'.

shift [N] ARRAYNAME.  Without ARRAYNAME, it's is the 'shift [N]' that
is already in bash. There is no quagmire. If the parameter following 'shift'
is a number, it's a count.  If it isn't a number, its an ID.  Even
though my example and the subject showed the 'count' first, the order
really doesn't matter if you think about it...

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