Re: (and scheme lisp) x Python and modern langs [was Re: gossip, Guy Steel, Lojban, Racket]
On 28 set, 19:38, Xah Lee xah...@gmail.com wrote: • “list comprehension” is a very bad jargon; thus harmful to functional programing or programing in general. Being a bad jargon, it encourage mis-communication, mis-understanding. I disagree: it is a quite intuitive term to describe what the expression does. • “list comprehension” is a redundant concept in programing. The concept is of historical interest. e.g. when people talk about the history of computer languages. The LC can simply be filter(map(func, list), predicate). I agree it is redundant. Like pretty much all syntax: all one needs is a way to define functions and to apply function to arguments (or assignment and pre-defined loops for imperative folks). Syntax may still be more convenient, though. Which is strange since you were an ardent syntax lover a few iterations ago. • The special syntax of “list comprehension” as it exists in many langs, are not necessary. It can simply be a plain function, e.g LC(function, list, filter). I disagree. Syntax may be redundant, but it is there to be convenient. I'll quote it again: For instance, this is far more convenient: [x+1 for x in [1,2,3,4,5] if x%2==0] than this: map(lambda x:x+1,filter(lambda x:x%2==0,[1,2,3,4,5])) but on the other hand, this is more convenient: map(inc,filter(evenp,[1,2,3,4,5])) (ignoring the lines of code for inc and evenp, of course. But as long as they are used in many parts, it *is* more convenient) In short, list comprehensions are useful syntatic expressions returning lists as long as you don't care for the short functions used in them. «do syntax does allow for imperative commands to be issued in scheme, just like let. It does not mean it was used in said examples nor that do is automatically inherently imperative just because of choice of name. imperative do - (do (steppers ...) (final-condition? result) malign-imperative-code-here ...)» i don't think your argument is forceful enough. It appears that by this argument you even say that “let” is not functional. In the case of Lisps, it depends on context: let is an expression returning a value, but Lisps are not purely functional languages and you *may* use imperative statements in the body, resulting in useful side-effect computations. That's why I said do is no more imperative than let: 1) because it *is* let and 2) because Lisps *allow* imperative constructs in the body of lambdas. do is not inherently imperative in the same sense Lisp/Scheme is not inherently imperative: they allow you to do purely functional evaluation of expressions but also to tint the computations with side-effects... your choice. So, overall, i consider your argument for “do” in Scheme lisp being functional is weak, or trivial. It seems to be a pet peeve. It is a pet peeve in that you call `do' imperative without arguments while a few other Schemers call `do' imperative on the basis of political bickering. Nobody gives `do' a chance of the base of it being what it is: a macro transform into let. Any imperative programming you do with `do' will get the same effect as if you do the same imperative programming with let. Imperative or functional, it's up to the user, not inherently from any language construct. You got annoyed because i seem to have ignored it entirely. But i got annoyed by you because you don't get the point about what i consider more significant opinion on “list comprehension”, which you totally ignored and kept at hacking the “do” in Scheme lisp. It's because I don't think I have much to comment on list comprehensions other than being useful syntax at times for an expression returning a list. -- http://mail.python.org/mailman/listinfo/python-list
Re: (and scheme lisp) x Python and modern langs [was Re: gossip, Guy Steel, Lojban, Racket]
On Sep 29, 11:02 am, namekuseijin namekusei...@gmail.com wrote: On 28 set, 19:38, Xah Lee xah...@gmail.com wrote: • “list comprehension” is a very bad jargon; thus harmful to functional programing or programing in general. Being a bad jargon, it encourage mis-communication, mis-understanding. I disagree: it is a quite intuitive term to describe what the expression does. what's your basis in saying that “list comprehension” is intuitive? any statics, survery, research, references you have to cite? to put this in context, are you saying that lambda, is also intuitive? “let” is intuitive? “for” is intuitive? “when” is intuitive? I mean, give your evaluation of some common computer language termilogies, and tell us which you think are good and which are bad, so we have some context to judge your claim. For example, let us know, in your view, how good are terms: currying, lisp1 lisp2, tail recursion, closure, subroutine, command, object. Or, perhaps expound on the comparative merits and meaning on the terms module vs package vs add-on vs library. I would like to see your view on this with at least few paragraphs of analysis on each. If you, say, write a essay that's at least 1k words on this topic, then we all can make some judgement of your familiarity and understanding in this area. Also, “being intuitive” is not the only aspect to consider whether a term is good or bad. For example, emacs's uses the term “frame”. It's quite intuitive, because frame is a common english word, everyone understands. You know, door frame, window frame, picture frame, are all analogous to emacs's “frame” on a computer. However, by some turn of history, in computer software we call such as “window” now, and by happance the term “window” also has a technical meaning in emacs, what we call “split window” or “pane” today. So, in emacs, the term “frame” and “window” is confusing, because emacs's “frame” is what we call “window”, while emacs's “window” is what me might call a pane of a split window. So here, is a example, that even when a term is intuitive, it can still be bad. as another example, common understanding by the target group the term is to be used is also a important aspect. For example, the term “lambda”, which is a name of greek char, does not convey well what we use it for. The word's meaning by itself has no connection to the concept of function. The char happens to be used by a logician as a shorthand notation in his study of what's called “lambda calculus” (the “calculus” part is basically 1700's terminology for a systematic science, especially related to mechanical reasoning). However, the term “lambda” used in this way in computer science and programing has been long and wide, around 50 years in recent history (and more back if we trace origins). So, because of established use, here it may decrease the level of what we might think of it as a bad jargon, by the fact that it already become a standard usage or understanding. Even still, note that just because a term has establish use, if the term itself is very bad in many other aspects, it may still warrant a need for change. For one example of a reason, the argon will be a learning curve problem for all new generations. You see, when you judge a terminology, you have to consider many aspects. It is quite involved. When judging a jargon, some question you might ask are: • does the jargon convey its meaning by the word itself? (i.e. whether the jargon as a word is effective in communication) • how long has been the jargon in use? • do people in the community understand the jargon? (e.g. what percentage) each of these sample questions can get quite involved. For example, it calls for expertise in linguistics (many sub-fields are relevant: pragmatics, history of language, etymology), practical experience in the field (programing or computer science), educational expertise (e.g. educators, professors, programing book authors/teachers), scientific survey, social science of communication... also, you may not know, there are bodies of professional scientists who work on terminologies for publication. It is not something like “O think it's good, becus it is intuitive to me.”. I wrote about 14 essays on various jargons in past decade. You can find them on my site. i removed your arguments on other parts about “list comprehension”, because i didn't find them valuable. (barely read them) However, i appreciate your inputs on the “do” in Scheme lisp has a functional usage, and some other misc chat info from the beginning of this thread on comp.lang.lisp. Xah ∑ xahlee.org ☄ -- http://mail.python.org/mailman/listinfo/python-list
Re: (and scheme lisp) x Python and modern langs [was Re: gossip, Guy Steel, Lojban, Racket]
On Wed, Sep 29, 2010 at 2:46 PM, Xah Lee xah...@gmail.com wrote: what's your basis in saying that “list comprehension” is intuitive? any statics, survery, research, references you have to cite? to put this in context, are you saying that lambda, is also intuitive? “let” is intuitive? “for” is intuitive? “when” is intuitive? I mean, give your evaluation of some common computer language termilogies, and tell us which you think are good and which are bad, so we have some context to judge your claim. For example, let us know, in your view, how good are terms: currying, lisp1 lisp2, tail recursion, closure, subroutine, command, object. Or, perhaps expound on the comparative merits and meaning on the terms module vs package vs add-on vs library. I would like to see your view on this with at least few paragraphs of analysis on each. If you, say, write a essay that's at least 1k words on this topic, then we all can make some judgement of your familiarity and understanding in this area. Have you actually written an essay on this topic of the sort that you are requesting here? I googled your site, but all I could find was your Perl-Python tutorial in which you simply stated that This construct has acquired a [sic] incomprehensible name 'list comprehension' in computing industry and academia. The obvious pun aside, I don't understand why you find the name to be incomprehensible. All it means is that the list is being defined by comprehension (i.e. intension) in the logical sense, as opposed to the more common extensive definition (e.g. myList = [1, 2, 3]). The suggestion that this nomenclature is any more obscure than lambda, in either origin or industry, is dubious to me. -- http://mail.python.org/mailman/listinfo/python-list
Re: (and scheme lisp) x Python and modern langs [was Re: gossip, Guy Steel, Lojban, Racket]
On 29 set, 17:46, Xah Lee xah...@gmail.com wrote: On Sep 29, 11:02 am, namekuseijin namekusei...@gmail.com wrote: On 28 set, 19:38, Xah Lee xah...@gmail.com wrote: • “list comprehension” is a very bad jargon; thus harmful to functional programing or programing in general. Being a bad jargon, it encourage mis-communication, mis-understanding. I disagree: it is a quite intuitive term to describe what the expression does. what's your basis in saying that “list comprehension” is intuitive? it generates a list from syntax comprehended in list-like syntax! any statics, survery, research, references you have to cite? how about common sense? to put this in context, are you saying that lambda, is also intuitive? No. “let” is intuitive? yes, it's focking everyday term used in the same way: let this be this and that be that and thus... “for” is intuitive? yes, it's focking everyday term used in the same way: for this and this and this do that... “when” is intuitive? when this, then that? common sense, Xah! For example, let us know, in your view, how good are terms: currying, lisp1 lisp2, tail recursion, closure, subroutine, command, object. These terms have a technical meaning coming from historic events in the areas they are used. It's like that in all areas, you may also bash medicine jargon if you want. Though subroutine, command and object are pretty intuitive by common sense alone. perhaps expound on the comparative merits and meaning on the terms module vs package vs add-on vs library. I would like to see your view on this with at least few paragraphs of analysis on each. They are all the same shit. These were developed by managers and buzzwriters... ;) Also, “being intuitive” is not the only aspect to consider whether a term is good or bad. For example, emacs's uses the term “frame”. It's quite intuitive, because frame is a common english word, everyone understands. You know, door frame, window frame, picture frame, are all analogous to emacs's “frame” on a computer. However, by some turn of history, in computer software we call such as “window” now, and by happance the term “window” also has a technical meaning in emacs, what we call “split window” or “pane” today. So, in emacs, the term “frame” and “window” is confusing, because emacs's “frame” is what we call “window”, while emacs's “window” is what me might call a pane of a split window. So here, is a example, that even when a term is intuitive, it can still be bad. emacs is all FUBAR in more than one way. being intuitive is not exactly what it is known for... ;) well, I shouldn't be bashing it, my vim is not that funky among commoners anymore anyway... :p I wrote about 14 essays on various jargons in past decade. You can find them on my site. yeah, I've read them once in a while... -- http://mail.python.org/mailman/listinfo/python-list
Re: (and scheme lisp) x Python and modern langs [was Re: gossip, Guy Steel, Lojban, Racket]
On 2010-09-30, namekuseijin namekusei...@gmail.com wrote: it generates a list from syntax comprehended in list-like syntax! Okay, help me out here. (Killed the crossposting.) I am not understanding how the word applies. I'm fine with it, but I don't see any relation at all between the thing called a list comprehension and the word comprehension as I normally understand it. Who or what is doing the comprehending? Is this a sense of comprehension other than to understand? It seems like it's perhaps related to comprehensive. However, I've never seen comprehension used to refer to anything other than understanding prior to encountering list comprehensions. [... hmm. maybe time to go searching...] Looking around, it seems this is from mathematical jargon, to wit, set comprehensions. Since I hadn't run into that jargon, I had no clue what the etymology was, and comprehended is not a verb I would ever have used with this. However, looking around, it appears that this usage also occurs in the same jargon; once you've got one of them the other follows. I guess the key, though, is that this is purely jargon, and jargon from another field -- not all programmers have done all mathematics. I even took a ton of bonus math in college, but happened not to have done anything where this terminology was used. So the usage is, pardon the pun, incomprehensible to me to begin with, and saying it's called a comprehension because it's comprehended doesn't help -- that's two forms of the same unfamiliar jargon. Of course, the jargon is pretty reasonable as such goes, in no small part because of the plain English sense of comprehensive in the sense of covering something completely, so it's not awful. But from where I'm coming, it would be every bit as obvious to call it a list exhaustion, by analagous derivation from exhaustive. -s -- Copyright 2010, all wrongs reversed. Peter Seebach / usenet-nos...@seebs.net http://www.seebs.net/log/ -- lawsuits, religion, and funny pictures http://en.wikipedia.org/wiki/Fair_Game_(Scientology) -- get educated! I am not speaking for my employer, although they do rent some of my opinions. -- http://mail.python.org/mailman/listinfo/python-list
Re: (and scheme lisp) x Python and modern langs [was Re: gossip, Guy Steel, Lojban, Racket]
xah wrote: in anycase, how's “do” not imperative? On Sep 28, 6:27 am, namekuseijin namekusei...@gmail.com wrote: how's “do” a “named let”? can you show example or reference of that proposal? (is it worthwhile?) I'll post it again in the hope you'll read this time: (do ((i 0 (+ 1 i)) ; i initially 1, (+ 1 i) at each step (r 0 (+ i r))) ; r initially 0, (+ i r) at each step (( i 5) r)) ; when i5, return r = 15 it's merely a macro (syntax) that gets transformed into this: (let loop ((i 0) (r 0)) (if ( i 5) r (loop (+ 1 i) (+ i r = 15 which is merely a macro that essentially gets transformed into this: ((lambda (loop) (loop loop 0 0)) (lambda (loop i r) (if ( i 5) r (loop loop (+ 1 i) (+ i r) = 15 which, as you can see, is merely function application. There's nothing there except evaluation of arguments, application of arguments to function and function return. It's not because they chose `do', or `for' or `while' for naming such syntax, that it behaves the same as their imperative homographs. as i said, regarding do: “do” in general in any lang is simply impreative. We don't even have to know the details. I don't care whatnot fuck proposal from whatnot lisp of what's actually going on. If it is named “do”, it is imperative. It's not: one can name factorial do. It's just a name. Who doesn't like do? It's short, to the point... ultimately, all lang gets transformed at the compiler level to become machine instructions, which is imperative programing in the ultimate sense. You say that “do” is merely macro and ultimately function application. But to what level should we go down this chain on how the language actually works when evaluating a function in source code? any functional lang, quickly becomes imperative when compiled to some intermediate code or interpreted. In a sense, it can't be any other way. Functions are abstract mathematical ideas, while “do” loop or any instruction are actual steps of algorithms. Xah ∑ xahlee.org ☄ -- http://mail.python.org/mailman/listinfo/python-list
Re: (and scheme lisp) x Python and modern langs [was Re: gossip, Guy Steel, Lojban, Racket]
2010-09-28 On Sep 28, 12:07 pm, namekuseijin namekusei...@gmail.com wrote: On 28 set, 14:56, Xah Lee xah...@gmail.com wrote: ultimately, all lang gets transformed at the compiler level to become machine instructions, which is imperative programing in the ultimate sense. You say that “do” is merely macro and ultimately function application. But to what level should we go down this chain on how the language actually works when evaluating a function in source code? any functional lang, quickly becomes imperative when compiled to some intermediate code or interpreted. In a sense, it can't be any other way. Functions are abstract mathematical ideas, while “do” loop or any instruction are actual steps of algorithms. That is true as of Mathematica too. Difference being that do in scheme is pretty-much user-level syntax. If you look in most (good) implementations sources, do and let are defined in scheme itself, not C or lower-level: C code only deals with transforming lambda application and tail calls into proper gotos. So, as far as we're talking about scheme, haskell or Mathematica code, it's all functional in its abstraction context. do syntax does allow for imperative commands to be issued in scheme, just like let. It does not mean it was used in said examples nor that do is automatically inherently imperative just because of choice of name. imperative do - (do (steppers ...) (final-condition? result) malign-imperative-code-here ...) so, now that we got it clear why do in scheme is not (inherently) imperative why were you bashing useful (at times) functional syntax in the form of list comprehensions again? le's get precise. The argument i want to make, is this: • “list comprehension” is a very bad jargon; thus harmful to functional programing or programing in general. Being a bad jargon, it encourage mis-communication, mis-understanding. • “list comprehension” is a redundant concept in programing. The concept is of historical interest. e.g. when people talk about the history of computer languages. The LC can simply be filter(map(func, list), predicate). • The special syntax of “list comprehension” as it exists in many langs, are not necessary. It can simply be a plain function, e.g LC(function, list, filter). I gave a stand-alone explanation of these points at: http://groups.google.com/group/comp.lang.lisp/msg/329b3b68ff034453 Do you disagree or agree with the above? This is the point _I_ want to argue about, but you don't seem to admit any part of it, but you seems to want to discuss about “do” in Scheme lisp being functional. So, perhaps we can now focus on this subject: The “do” in Scheme lisp is not imperative, or, it can be considered as functional. Alright. To be honest, i haven't had enough experience to comment on, but in general, i understand the example you've given, and i disagree. Full report on your argument on this is given at: http://groups.google.com/group/comp.lang.lisp/msg/87a987070e80231f Now, in your message (quoted above), you made further argument on this. I think the main point is this, quote: «do syntax does allow for imperative commands to be issued in scheme, just like let. It does not mean it was used in said examples nor that do is automatically inherently imperative just because of choice of name. imperative do - (do (steppers ...) (final-condition? result) malign-imperative-code-here ...)» i don't think your argument is forceful enough. It appears that by this argument you even say that “let” is not functional. Here, the issue verges on what is functional? What is a function? If a function in lisp is defined as macro, does it ceases to be considered as a function? Likewise, if a lisp's has “for” loop that is defined as a macro, is that “for” now considered a function? this is getting quite iffy. What level or aspect are we considering? In each lang, usually they define certain terms specifically to the lang, and to various degree of precision. For eample, the term “object” means very different things in a technical way in different langs. Same for the word “function”, “keyword”, “command”, “module”, “package” ... So, overall, i consider your argument for “do” in Scheme lisp being functional is weak, or trivial. It seems to be a pet peeve. You got annoyed because i seem to have ignored it entirely. But i got annoyed by you because you don't get the point about what i consider more significant opinion on “list comprehension”, which you totally ignored and kept at hacking the “do” in Scheme lisp. Xah ∑ xahlee.org ☄ -- http://mail.python.org/mailman/listinfo/python-list
Re: (and scheme lisp) x Python and modern langs [was Re: gossip, Guy Steel, Lojban, Racket]
2010-09-27 For instance, this is far more convenient: [x+1 for x in [1,2,3,4,5] if x%2==0] than this: map(lambda x:x+1,filter(lambda x:x%2==0,[1,2,3,4,5])) How about this: LC(func, inputList, P) compared to [func for myVar in inputList if P] the functional form is: • shorter • not another idiysyncratic new syntax now, a separate issue. Suppose we want some “list comprehension” feature in a functional lang. Normally, by default this can be done by filter( map(func, inputList), Predicate) but perhaps this usage is so frequent that we want to create a new fuction for it, to make it more convenient, and perhaps easier to make the compiler to optimize more. e.g. LC(func, inputList, Predicate) this is about whether a lang should create a new convenient function that otherwise require 2 function combinations. Common Lisp vs Scheme Lisp are the typical example of extreme opposites. note, there's no new syntax involved. Now, let's consider another separated issue related to so-called “list comprehension”. Suppose we decided that generating list by a filter is so frequently used that it worth it to create a new func for it. LC(func, inputList, Predicate) Now, in functional langs, in general a design principle is that you want to reduce the number of function unless you really need. Because, any combination of list related functions could potentionally be a new function in your lang. So, if we really think LC is useful, we might want to generalize it. e.g. in LC(func, inputList, Predicate) is it worthwhile say to add a 4th param, that says return just the first n? (here we presume the lang doesn't support list of infinite elements) e.g. LC(func, inputList, Predicate, n) what about partition the list to m sublists? LC(func, inputList, Predicate, n, m) what about actualy more generalized partition, by m sublist then by m1 sublist then by m2 sublist? LC(func, inputList, Predicate, n, list(m,m1,m2,...)) what about sorting? maybe that's always used together when you need a list? LC(func, inputList, Predicate, n, list(m,m1,m2,...), sortPredcate) what if actually frequently we want LC to map parallel to branches? e.g. LC(func, inputList, Predicate, n, list(m,m1,m2,...), sortPredcate, mapBranch:True) what if ... you see, each of these or combination of these can be done by default in the lang by sequenceing one or more functions (i.e. composition). But when we create a new function, we really should think a lot about its justification, because otherwise the lang becomes a bag of functions that are non-essential, confusing. In summary: • “list comprehension” is a bad jargon. • The concept of “list comprehension” is redundant. There's no justification for the concept to exist except historical. • The syntax of “list comprehension” in most lang is ad hoc syntax. for those who find imperative lang good, then perhaps “list comprehension” is good, because it adds another idiosyncratic syntax to the lang, but such is with the tradition of imperative langs. The ad hoc syntax aids in reading code by various syntactical forms and hint words such as “[... for ... in ...]”. Xah ∑ xahlee.org ☄ -- http://mail.python.org/mailman/listinfo/python-list
Re: (and scheme lisp) x Python and modern langs [was Re: gossip, Guy Steel, Lojban, Racket]
On 27 set, 16:06, Xah Lee xah...@gmail.com wrote: 2010-09-27 For instance, this is far more convenient: [x+1 for x in [1,2,3,4,5] if x%2==0] than this: map(lambda x:x+1,filter(lambda x:x%2==0,[1,2,3,4,5])) How about this: [snip] how about this: read before replying. -- http://mail.python.org/mailman/listinfo/python-list
Re: (and scheme lisp) x Python and modern langs [was Re: gossip, Guy Steel, Lojban, Racket]
On Sep 27, 12:11 pm, namekuseijin namekusei...@gmail.com wrote: On 27 set, 16:06, Xah Lee xah...@gmail.com wrote: 2010-09-27 For instance, this is far more convenient: [x+1 for x in [1,2,3,4,5] if x%2==0] than this: map(lambda x:x+1,filter(lambda x:x%2==0,[1,2,3,4,5])) How about this: [snip] how about this: read before replying. hum??? i read your post quite carefully, and rather thought i replied well. In fact, i really wanted to tell you “read before replying” before but refrained from making any of that expression. here's 2 previous posts about list compre. http://groups.google.com/group/comp.lang.lisp/msg/145f6ecf29ebbdaf http://groups.google.com/group/comp.lang.lisp/msg/62ca84062c9fcdca Xah -- http://mail.python.org/mailman/listinfo/python-list
Re: (and scheme lisp) x Python and modern langs [was Re: gossip, Guy Steel, Lojban, Racket]
On 27 set, 18:39, Xah Lee xah...@gmail.com wrote: On Sep 27, 12:11 pm, namekuseijin namekusei...@gmail.com wrote: On 27 set, 16:06, Xah Lee xah...@gmail.com wrote: 2010-09-27 For instance, this is far more convenient: [x+1 for x in [1,2,3,4,5] if x%2==0] than this: map(lambda x:x+1,filter(lambda x:x%2==0,[1,2,3,4,5])) How about this: [snip] how about this: read before replying. hum??? i read your post quite carefully, and rather thought i replied well. I don't think so. You completely missed the point where I agreed about filter map being more convenient when calling predefined functions and also the detailed explanation of why do in scheme is not imperative at all. -- http://mail.python.org/mailman/listinfo/python-list
