A question (confusion) about closure
in [Lisp]
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From: Tim X on 7 May 2008 05:55 Don Geddis <don(a)geddis.org> writes: > "xahlee(a)gmail.com" <xahlee(a)gmail.com> wrote on Sun, 4 May 2008 : >> If there are 4 lisp programers, most or all of which i think are >> experienced, and all claim that i was wrong, how can i be right? > > At the very least, you ought to more seriously consider the possibility > that you are wrong. > >> I'm guessing my problem has to do with my personality. A normal person, >> would probably just discuss the issue in earnest. Like, we all human >> beings, some knows some areas better, and we all make mistakes. A >> discussion can just carry on in its course, and everyone can just learn >> something or simply enjoy the conversation. But Noooo! I can't be like >> that. > > That does sound like a problem with your personality, just as you suspected. > > Perhaps you'd make more progress if you'd work on this particular problem. > >> Still, it troubles me deeply, how could a patently simple explanation, a >> simple concept, a penetrating view, be not clearly grasped by a gaggle of >> lispers? In this thread, there are 15 messages. Not one reply, seems to >> indicate that what i said is correct. Almost half of them actually pointed >> out that i was incorrect, and even unhelpful. I'm greatly troubled by >> this. > > If it happened that you _were_ wrong, what kind of evidence do you think > you might see? > > I'm curious why you don't at least think about the case where you are not > correct. Might that explain all the reactions you're getting? > >> i'm rather quite surprised how my exposition of the closure concept >> turn up so many messages, many claiming it being even unhelpful or >> useless. > > If your theories of the world are constantly surprised by actual observations > of that world, at some point you need to consider that perhaps your theories > are in error. > > After all, the whole point of a theory is to make what happens later > predictable, not surprising. > I've re-read what Xah wrote and in addition to what you have pointed out I would add * Xah's skills with respect to writing are very poor. Reading followups to his posts and doing a bit of 'reading between the lines' often provides additional information that make his initial claims/rants/explinations a little easier to understand. Unfortunately, despite suggestions from many that he work on this skill in order to get his message across more effectively, it does not appear he can handle any form of criticism without becoming totally defensive even when that criticism is presented in an obviously well meaning and patient way. See Kent's post in this thread and Xah's response. * From reading a number of his posts, it seems clear that Xah hopes to provide some level of demystification of many technical concepts. This is an admirable goal, but one which is undermined by his poor communication skills. However, he often makes the mistake of over simplification. This immediately makes others respond with claims that he is wrong. In reality, I suspect that he is not strictly wrong, but rather presents an overly simplistic explination that unfortunately is potentially misleading. For example, in this current thread on closures, I get the impression that Zah is providing an explination via an over simplistic analagy that essentially says that a closure is a technique to create a function that has its own private storage that can maintain a sort of function state. His use of the term global variable has muddied the waters and clouded the message I suspect he was trying to get across. His claim he can do closures using global variables is misleading as I suspect what he really means is that you could simulate the same properties using such variables. His point could possibly have been less contentious if he had concentrated on using an analagy closer to that of objects. His references to using global variables glosses over the limitations and complexities that would be involved in getting only the most basic properties of a closure in his simulated version. However, the most misleading aspect of his explination is that it effectively makes closures seem like nothing but a 'cute' programming trick and is likely to make some feel that it has no relevance and no practicle application in the real world. * Xah's claims that no other languages other than CL use closures is also incorrect and shows that while he may have some grasp of theoretical mathematical concepts, he has little understanding of many of the languages he tries to speak about with authority. For example, the first place I came across closures was in perl and in a real-world application. This was one of the languages that he claimed didn't use closures. * I suspect Xah suffers from some form of paranoia or related personality disorder and can't help but see any level of criticism as a personal attack. He seems unable or at least unwilling to actually consider that he may actually cause the 'attacks' he recieves and is unable to recognise his own contribution to the situation. The whole rest of the world is wrong and he is the only one who is right. It reminds me of a programmer I once worked with. He was quite a good programmer and quite intelligent, but was never able to recognise his own role in creating bugs. Whenever he was having trouble finding a bug in a bit of code, he would immediately start suspecting bugs in the language, OS or a virus. I'd point out how unlikely it was for him to have tripped over a bug in the language (At the time, we were working in C) and that it was almost certainly a bug in his code. He refused to believe it - logged bug reports with the compiler vendor, got the sys admins to check for viruses and blamed all the libraries we were using. In the end, it turned out to be a bit of his code that was attempting to access memory via a pointer that had already been passed to free(). Apart from this occuring when viruses were still quite new and rare and apart from the fact that this would have to be one of the most common bugs you encounter in C, the real issue was that he simply couldn't see his own part in the equation - his code was perfect and it had to be something else not him. Xah is like that programmer. * I've noticed that Xah posts on a wide variety of topics and seems to produce a huge amount of output. Despite the fact that most of what I have read of his work could be reduced by half and be a lot clearer and more succinct if only he tried to refine his style and applied some rigor to his editing, I find that with only a few exceptions, his analysis seems shallow and lacking in any evidence of real depth of knowledge and understanding. It is possible that this is due to his poor expressive skills, but i suspect that he is reasonably intelligent and has a broad but shallow grasp of many topics. This in itself is fine, but anyone who really wants to explain difficult or even not so difficult topics really needs to have a very solid understanding before attempting to explain it to others who do not. Anyway, I'll leave it at that. In conclusion, I suspect Xah isn't quite as incorrect as most of us initially thought, but as Kent points out, his style of expression makes it very difficult to know for certain. This combined with a tendency to over simplify tends to get the wrong response and probably makes him worse and in the end it all just ends up with the same pointless threads going around in a circle. Tim P.S. Xah, if you read this, save yourself the effort. I know you want to respond and tell me how much you hate me and how I should go back to school/college/homework and that you are perfect and misunderstood blah blah blah. Its predictable and boring. Lets just assume you have responded and insults from a faceless paranoid in another country has scarred me for life. I'll organise some councelling tomorrow to help me get over it. BTW: You are wrong in your assumption regarding my age and what I do. I finished school before you were even born and have more life behind me than I have left in front. My first paid job with computers was so long ago its just a hazy memory of punch cards and a wonderful new aid to productivity, the tty. (Actually, I've still got a few boxes of punch cards - I find them very useful for making notes as they fit quite nicely in your shirt pocket (doubled over that is). -- tcross (at) rapttech dot com dot au
From: Tim X on 7 May 2008 06:02 George Neuner <gneuner2/@/comcast.net> writes: > > I think we probably could all cut Xah some slack provided he stops the > rude name-calling. > I tend to agree. If he showed some level of willingness to address responses based on the content of the response rather than just personally attacking the poster and if he showed some willigness to even consider that sometimes he may either be wrong, over simplistic or willing to learn or expand his ideas based on input from others, then possibly everyone including Xah could benefit in different ways. Tim -- tcross (at) rapttech dot com dot au
From: John Thingstad on 7 May 2008 06:22 P� Wed, 07 May 2008 10:01:58 +0200, skrev Didier Verna <didier(a)lrde.epita.fr>: > pjb(a)informatimago.com (Pascal J. Bourguignon) wrote: > >> And yes, this include several MUAs entirely written in emacs lisp, so >> if it's not fine to do that, at least it doesn't discourrage emacs >> lisp programmers... > > Right :-) You can always knock in a nail with a screw driver. You just > wish you had a hammer ;-) > > But to be really fair, once you get a hammer, it doesn't mean you know > how to use it properly. So part of the problem we have today is also due > to extremely bad design and ugly code in most elisp lines out there. > > So on the one hand, we have elisp code, mostly a collection of crappy > hacks on top of each other, but it works... and I'm really wondering, if > a standard elisp object system had existed in the first place, would the > original programmers have been skilled enough to use it and design their > stuff properly ? > > On the other hand, we have XEmacs code base, which is very well designed > and abstracted, OO actually[1], but it is written in C with a bunch of > ugly > macrology on top because it is rather hard to object-orient plain C > code... > erm. emacs is a evolved system that worked the whole time while they added code. If you had 'designed' it with the current features I doubt if it would ever have worked in the first place. Another question is if OO design would have made it 'better' or just more 'familiar'. -------------- John Thingstad
From: Didier Verna on 7 May 2008 07:55 "John Thingstad" <jpthing(a)online.no> wrote: > emacs is a evolved system that worked the whole time while they added > code. If you had 'designed' it with the current features I doubt if it > would ever have worked in the first place. If not in the first place, emacs lisp code could have evolved if elisp itself had; but that didn't really happen. At some point (I mean right now), perhaps starting from scratch again would be better than refactoring. > Another question is if OO design would have made it 'better' or just > more 'familiar'. Right. Not all parts would necessarily benefit from object orientation, but some definitely would. What's more (at least in the case of XEmacs), some parts already *are* object-oriented; just not in an OO language which is a real PITA. Refactoring those parts with a more modern tool underneath would not be difficult, because the design is already there. -- 5th European Lisp Workshop at ECOOP 2008, July 7: http://elw.bknr.net/2008/ Didier Verna, didier(a)lrde.epita.fr, http://www.lrde.epita.fr/~didier EPITA / LRDE, 14-16 rue Voltaire Tel.+33 (0)1 44 08 01 85 94276 Le Kremlin-Bic�tre, France Fax.+33 (0)1 53 14 59 22 didier(a)xemacs.org
From: viper-2 on 7 May 2008 09:50
On May 6, 4:00 pm, Rainer Joswig <jos...(a)lisp.de> wrote: > In article > <2f9bb421-187a-4820-a515-03fc41d14...(a)m45g2000hsb.googlegroups.com>, > > Well, you have to read for example the mentioned > Lisp Machine Window System Manual (available as PDF). > On page 2 there is a 'Note from Richard Stallman', > where he writes in what is clearly his style: > > "The current implementation of the window system is based on > flavors, and was designed and implemented primarily by Howard > Cannon and Mike McMahon during 1980. It replaced an > earlier version implemented by me, which was based on > Smalltalk-like classes. The newer system is generally an > improvement, but as Howard Cannon steadfastly refused > to discuss the design with me I must decline responsibility > for such counterintuitive aspects as the definition of > exposure." Noted. BTW Rainer, you have nice name.:-) agt |