[Python-Dev] lambda in Python
Today i ran into one of Guido van Rossum's blog article titled “Language Design Is Not Just Solving Puzzles” at http://www.artima.com/weblogs/viewpost.jsp?thread=147358 The article reads very kooky. The bottom line is that Guido simply does not like the solution proposed for fixing the lambda construct in Python, and for whatever reasons thinks that no solution would satisfy him about this. But instead, he went thru sophistry on the ignorance and psychology of coder mass in the industry, with mentions of the mysterious Zen, the cool Google, the Right Brain, Rube Goldberg contraption irrelevancies. From his article, i noticed that there's largish thread of discussions on lambda. The following is a essay i wrote after reading another one of Guido blog, in which shows prejudice and ignorance about functional programing. I hope it can reduce the ignorance about lambda and functional programing. -- Lambda in Python 3000 Xah Lee, 20050930 On Guido van Rossum's website: http://www.artima.com/weblogs/viewpost.jsp?thread=98196 (local copy) dated 20050310, he muses with the idea that he would like to remove lambda, reduce(), filter() and map() constructs in a future version Python 3000. Guido wrote: «filter(P, S) is almost always written clearer as [x for x in S if P(x)], and this has the huge advantage that the most common usages involve predicates that are comparisons, e.g. x==42, and defining a lambda for that just requires much more effort for the reader (plus the lambda is slower than the list comprehension)» The form “[x for x in S if P(x)]” is certainly not more clear than “filter(P, S)”. The latter is clearly a function, what is the former? A function every programer in any language can understand and appreciate its form and function. Why would anyone to expect everyone to appreciate a Python syntactical idiosyncrasy “[x for ...]”? Also, the argument that the form “filter(F,S)” being cumbersome because the first argument is a function and that mostly likely it would be a function that returns true/false thus most people will probably use the inline “lambda” construct and that is quite cumbersome than if the whole thing is written with the syntactical idiosyncrasy “[x for ...]”, is rather inane, as you can now see. The filter(decision_function,list) form is clean, concise, and helps thinking. Why it helps thinking? Because it condenses the whole operation into its mathematical essence with the most clarity. That is, it filters, of a list, and by a yes/no decision function. Nothing is more, and nothing can be less. It is unfortunate that we have the jargon Lambda and Predicate developed by the tech geekers of the functional programing community. The lambda could be renamed Pure Function and the Predicate could be called True/False function, but the world of things being the way they are already, it is unwise to rewrite every existing Perl program just because somebody invented another language. If the predicate P in filter(P,S) is cumbersome, so would exactly the same thing appear in the syntactical idiosyncrasy: “[x for x in S if P(x)]”. Guido added this sting as a afterthought: «(plus the lambda is slower than the list comprehension)» Which is faster is really the whim and capacity of Python compiler implementators. And, weren't we using clarity as the judgement a moment ago? The concept of a function every programer understands, but what the heck is a List Comprehension? Why don't you scrap list comprehension in Python 3000 and create a table() function that's simpler in syntax and more powerful in semantics? ( See http:// xahlee.org/perl-python/list_comprehension.html ) «Why drop lambda? Most Python users are unfamiliar with Lisp or Scheme, so the name is confusing; also, there is a widespread misunderstanding that lambda can do things that a nested function can't -- I still recall Laura Creighton's Aha!-erlebnis after I showed her there was no difference! Even with a better name, I think having the two choices side-by-side just requires programmers to think about making a choice that's irrelevant for their program; not having the choice streamlines the thought process. Also, once map(), filter() and reduce() are gone, there aren't a whole lot of places where you really need to write very short local functions; Tkinter callbacks come to mind, but I find that more often than not the callbacks should be methods of some state-carrying object anyway (the exception being toy programs).» In the outset Guido here assumes a moronitude about the set of Python users and what they are familiar of. Python users 10 years ago are not the same Python users today, and will certainly not be the same 10 years later if you chop off lambda. Things change, math literacy advances, and what users you have changes with what you are. A function is the gist
Re: [Python-Dev] lambda in Python
I do not wish to be the subject of mobbing here. If you have opinions on what i wrote, respond to the subject on topic as with any discussion. Please do not start a gazillion war-cry on me. If you cannot tolerate the way i express my opinions, at this moment write a polite request to me and cc to the sys op of this forum. If the sysop deems fit, I'd be happy to be asked to leave by the sysop. Thanks. Xah [EMAIL PROTECTED] ∑ http://xahlee.org/ On 2006 May 4, at 6:21 AM, Jay Parlar wrote: On May 4, 2006, at 6:00 AM, Talin wrote: > xahlee xahlee.org> writes: > >> Today i ran into one of Guido van Rossum's blog article titled >> ?Language Design Is Not Just Solving Puzzles? at >> http://www.artima.com/weblogs/viewpost.jsp?thread=147358 > > The confrontational tone of this post makes it pretty much impossible > to have a reasonable debate on the subject. I'd suggest that if you > really want to be heard (instead of merely having that "I'm right" > feeling) that you try a different approach. > > -- Talin Xah Lee is a well known troll, he does stuff like this on c.l.p. all the time. Best to just ignore him, he doesn't listen to reason. Jay P. ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/xah% 40xahlee.org ☄ ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
[Python-Dev] A critic of Guido's blog on Python's lambda
In this post, i'd like to deconstruct one of Guido's recent blog about lambda in Python. In Guido's blog written in 2006-02-10 at http://www.artima.com/ weblogs/viewpost.jsp?thread=147358 is first of all, the title “Language Design Is Not Just Solving Puzzles”. In the outset, and in between the lines, we are told that “I'm the supreme intellect, and I created Python”. This seems impressive, except that the tech geekers due to their ignorance of sociology as well as lack of analytic abilities of the mathematician, do not know that creating a language is a act that requires little qualifications. However, creating a language that is used by a lot people takes considerable skill, and a big part of that skill is salesmanship. Guido seems to have done it well and seems to continue selling it well, where, he can put up a title of belittlement and get away with it too. Gaudy title aside, let's look at the content of his say. If you peruse the 700 words, you'll find that it amounts to that Guido does not like the suggested lambda fix due to its multi-line nature, and says that he don't think there could possibly be any proposal he'll like. The reason? Not much! Zen is bantered about, mathematician's impractical ways is waved, undefinable qualities are given, human's right brain (neuroscience) is mentioned for support, Rube Goldberg contrivance phraseology is thrown, and coolness of Google Inc is reminded for the tech geekers (in juxtaposition of a big notice that Guido works there.). If you are serious, doesn't this writing sounds bigger than its content? Look at the gorgeous ending: “This is also the reason why Python will never have continuations, and even why I'm uninterested in optimizing tail recursion. But that's for another installment.”. This benevolent geeker is gonna give us another INSTALLMENT! There is a computer language leader by the name of Larry Wall, who said that “The three chief virtues of a programmer are: Laziness, Impatience and Hubris” among quite a lot of other ingenious outpourings. It seems to me, the more i learn about Python and its leader, the more similarities i see. So Guido, i understand that selling oneself is a inherent and necessary part of being a human animal. But i think the lesser beings should be educated enough to know that fact. So that when minions follow a leader, they have a clear understanding of why and what. Regarding the lambda in Python situation... conceivably you are right that Python lambda is perhaps at best left as it is crippled, or even eliminated. However, this is what i want: I want Python literatures, and also in Wikipedia, to cease and desist stating that Python supports functional programing. (this is not necessarily a bad publicity) And, I want the Perl literatures to cease and desist saying they support OOP. But that's for another installment. This post is archived at: http://xahlee.org/UnixResource_dir/writ/python_lambda_guido.html Xah [EMAIL PROTECTED] ∑ http://xahlee.org/ ☄ ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
