Path: csiph.com!goblin1!goblin.stu.neva.ru!usenet.stanford.edu!not-for-mail From: L A Walsh Newsgroups: gnu.bash.bug Subject: Re: comment on RFE: 'shift'' [N] ARRAYNAME Date: Thu, 27 Sep 2018 10:56:45 -0700 Lines: 39 Approved: bug-bash@gnu.org Message-ID: References: <5BAAD017.4010806@tlinx.org> <20180927123551.j5attjixprhoxavx@eeg.ccf.org> NNTP-Posting-Host: lists.gnu.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: usenet.stanford.edu 1538071021 11931 208.118.235.17 (27 Sep 2018 17:57:01 GMT) X-Complaints-To: action@cs.stanford.edu To: bug-bash@gnu.org Envelope-to: bug-bash@gnu.org User-Agent: Thunderbird In-Reply-To: <20180927123551.j5attjixprhoxavx@eeg.ccf.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x (no timestamps) [generic] [fuzzy] X-Received-From: 173.164.175.65 X-BeenThere: bug-bash@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Bug reports for the GNU Bourne Again SHell List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Xref: csiph.com gnu.bash.bug:14675 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 >> incompatibility? >> > > 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...