From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.help Subject: Re: What does "lacks a prefix" mean? Date: Sun, 12 Jul 2015 03:47:07 +0200 Message-ID: <87d1zydu5g.fsf@nl106-137-147.student.uu.se> References: <1e0ad02f-ca3e-495c-bb85-61f77090d31d@googlegroups.com> <87bnfmqzn2.fsf@kuiper.lan.informatimago.com> > > <082e0be8-425b-4eff-8473-0c1091628695@default> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1436665739 7781 80.91.229.3 (12 Jul 2015 01:48:59 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 12 Jul 2015 01:48:59 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sun Jul 12 03:48:50 2015 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZE6Nu-0001QB-8P for geh-help-gnu-emacs@m.gmane.org; Sun, 12 Jul 2015 03:48:50 +0200 Original-Received: from localhost ([::1]:49487 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZE6Nt-0004jz-N3 for geh-help-gnu-emacs@m.gmane.org; Sat, 11 Jul 2015 21:48:49 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:38180) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZE6Ni-0004ji-J0 for help-gnu-emacs@gnu.org; Sat, 11 Jul 2015 21:48:40 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZE6Nf-00020o-C1 for help-gnu-emacs@gnu.org; Sat, 11 Jul 2015 21:48:38 -0400 Original-Received: from plane.gmane.org ([80.91.229.3]:44259) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZE6Nf-00020h-50 for help-gnu-emacs@gnu.org; Sat, 11 Jul 2015 21:48:35 -0400 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1ZE6Ne-0001Gf-3W for help-gnu-emacs@gnu.org; Sun, 12 Jul 2015 03:48:34 +0200 Original-Received: from nl106-137-156.student.uu.se ([130.243.137.156]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 12 Jul 2015 03:48:34 +0200 Original-Received: from embe8573 by nl106-137-156.student.uu.se with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sun, 12 Jul 2015 03:48:34 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: help-gnu-emacs@gnu.org Original-Lines: 88 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: nl106-137-156.student.uu.se Mail-Copies-To: never User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4 (gnu/linux) Cancel-Lock: sha1:Yr6eph9im4hrW/s1JCgannFdKNk= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:105616 Archived-At: Drew Adams writes: > Harm? Why would *harm* be the only useful or the > most useful criterion? > > There's no harm in writing Lisp with no whitespace > at all, except for that needed to distinguish tokens > such as symbols and numbers. > > And in fact I once had a colleague (an expert Lisper, > BTW) who wrote Lisp that way, always - no newline > chars, no indentation, no spaces or tabs at all, > except what was needed by the interpreter or > byte-compiler to disambiguate the code. > > No one else wanted to read, let alone modify his > code, but hey, no "harm" done, right? > > He wrote his code at lightning speed, hardly looking > at it. And his code was *good* code - for the > applications and the machine. It just wasn't very > good for humans (other than himself, arguably, and > I'm not sure he didn't shoot himself in the foot > sometimes). I do see the harm in doing as your former colleague but I don't see the harm in using `let*' instead of `let'. Apart from convention which can be reprogrammed in the minds of programmers, even. And, as it stands, apart from me not liking the syntax (spelling) of "let*" compared to "let". > I would say this about using `let' vs `let*' wrt > what they indicate to human readers: `let' indicates > that the bindings are independent; `let*' signals > that they might be dependent. > > I don't see a red flag from `let*', but yes, it does > make me pay attention and look for dependencies. > That "might be" is where I agree with Barry: `let*' > makes you look for whether each binding after the > first might in fact be dependent on a previous one > from the same `let*'. > > It's a huge load off one's mind knowing that the > bindings of a `let' are independent. Similarly, it > is a great help to know, from `let*', to look for > how the bindings are actually related. > > The problem with using `let*' all the time ("harm", > actually) is the problem of affixing the same > **WARNING** label to absolutely everything - it > loses all power to draw attention to anything. > If everwhere might involve binding dependencies then > you have no signal to watch for them. You need to > always be on the alert - or never. This all makes sense if the premise is that dependencies are anything to look for, be aware of, be "on the alert", as you say. But - why do you want to look for them at all? What does it matter? On the contrary, I consider them completely natural and a good thing. It is *good* for humans to see that computation is done in steps, and for machines, that is the way it happens anyway - it doesn't matter if you have one all but neverending line: (let ((value (computation_1 ( ... (computation_n ...)))))) or the same procedure on a vertical line with names to illustrate the process. But, to humans, it is more clear and less error prone, and it is easier to modify and debug. If we turn the discussion upside down, if dependencies indeed were a reason to be on the alert - then I'd like a much better and more specific construct than `let*'! If dependencies were something to look for, I wouldn't want a construct that says "here, there *might* be dependencies", instead I'd like a construct that said "here, there *is* a dependency, namely X depends on Y in terms of Z!" -- underground experts united http://user.it.uu.se/~embe8573