> They don't have the word "noun" in APL. I'm teaching J, not APL. For the cases you cite, instead of 'arrays or scalars' I simply say 'noun'. I have all the words I need. I like it that way.
,99 is, of course, an array. It is one element lined up. It's an army of one. It's a lot different from 99, and deserves a verbal distinction. Henry Rich On 10/25/2010 10:54 PM, Roger Hui wrote: >> But if I mean 'any scalar or array', I have the >> word 'noun' for that. > > They don't have the word "noun" in APL. > >> I just don't see why the word 'array', which in plain English denotes >> an arrangement of (multiple) things, should have to include scalars. >> Sue me. Or change the standard. > > Look at the texts I quoted. For example, the function > + takes arrays arguments, scalar or arrays of higher rank. > If arrays don't include scalars you'd constantly have to > say "arrays or scalars". You can not use "multiple" to > determine whether something is or is not an array, > for surely you would not say that ,99 or 1 1$99 or 1 1 1$99 > are not arrays? > > The APL standard uses "array" in that way for a good reason. > "Array or scalar" in APL is a fiction. I don't believe there is > anything in the APL literature that says that a scalar is > not an array. For the same good reason. > > > > ----- Original Message ----- > From: Henry Rich<[email protected]> > Date: Monday, October 25, 2010 19:11 > Subject: Re: [Jgeneral] "J In A Day" --crits please > To: General forum<[email protected]> > >> I teach the kids that 'scalar' and 'atom' mean a rank-0 thing, >> and >> 'array' means rank> 0. Yeah, I know it's not >> standard. But if I mean >> 'any scalar or array', I have the word 'noun' for that. >> And the >> distinction between scalar and array is important enough to have >> words for. >> >> My way, I can give them some simple things to memorize: >> >> An array is a list of its items. >> >> The items of an array have rank one less than the array. >> >> #array is the same as {.$array. >> >> A DLL descriptor of *c matches an array of characters. >> >> I just don't see why the word 'array', which in plain English >> denotes an >> arrangement of (multiple) things, should have to include scalars. >> Sue me. Or change the standard. >> >> Henry Rich >> >> >> On 10/25/2010 9:19 PM, Roger Hui wrote: >>> I had/have been an APLer for many years and I have >>> never heard of scalars not being arrays. As far as >>> I know 99 is not just now deemed an array but >>> have always been deemed an array. I'd be interested >>> in any APL reference you can find that says otherwise. >>> >>> A more ancient reference for that fact that a scalar is an array. >>> Falkoff and Iverson, The APL\360 Terminal System, 1967-10-16. >>> http://www.jsoftware.com/papers/APL360TerminalSystem.htm >>> >>> - A vector has a “rank” of one, the term being used, >>> as in tensor analysis, to mean the number of indices >>> required to identify a single element in an array. >>> Hence, a scalar has rank zero and a matrix has rank two. >>> >>> - No special notational convention is required for the >>> element-by-element extension, so that in the expression a+b , >>> for example, a and b may be any pair of matching arrays. >>> If one argument is a scalar the other may be any array, ... >>> >>> --- >>> >>> In any case, you have not addressed the practical point >>> I raised: if a scalar is not an array, you are going to >>> need a term for "array or scalar". Another way to >>> look at it is, why is it useful to distinguish between >>> an array and a scalar? >>> >>> Whether a scalar is an array is not a statement that >>> you can prove one way or the other, and you have to >>> decide on considerations in the preceding paragraph, >>> or considerations similar to same. >>> >>> Finally, why is it counter-intuitive that a scalar is >>> an array? >>> >>> >>> >>> ----- Original Message ----- >>> From: Ian Clark<[email protected]> >>> Date: Monday, October 25, 2010 17:44 >>> Subject: Re: [Jgeneral] "J In A Day" --crits please >>> To: General forum<[email protected]> >>> >>>> Thanks, Roger, for the ref to the ISO standard: ISO 13751. Wow, >>>> haven't things moved on since I was involved with the draft ISO >>>> standard in 1992. I'd buy myself a copy, but they want $292 just >>>> for a >>>> lousy PDF. But yes: thanks for reminding me the Dyalog >> manuals are >>>> free. >>>> >>>> No, I didn't really think you'd get it wrong. But I confess >> I'm amazed >>>> that scalar 99 is now deemed an "array"! I thought I knew APL, >>>> but I'd >>>> never heard that one. (Yes, I knew about rank zero.) >>>> >>>> I'm now going to ask all my APL friends: "did you know 99 is an >>>> array?" -- and see what they say. >>>> >>>> But you know what I think? I think it's counter-intuitive, >> and that's >>>> the sort of thing that gets APL a bad name. And not just APL... >>>> >>>> I refuse to get into disputes about which is the better >>>> language: APL >>>> or J. What's more, "reductio" arguments don't work with me either, >>>> unless I'm convinced we start from the same premises -- which >>>> I'm not. >>>> I've spent my programming career porting code, >> and there >>>> is no >>>> "better" or "worse" language for me. There is just a source >> and a >>>> target language. Which is which? Well, (1) who's paying? (2) >>>> which way >>>> does he want to migrate his code? >>>> >>>> I haven't touched APL for over a year now, but I've coded >>>> heavily in >>>> J. The reasons for that won't impress you. If you ask me >> which I have >>>> any warm feeling for, I have to say APL... in the same way a doctor >>>> prefers a sick patient to a healthy one. It's made me a living, >>>> and a >>>> good one. >>>> >>>> I've offered to write this crash-course for APLers. Some of >> them are >>>> proud of their skill in the language -- and they don't respond >>>> positively to having it dissed. I'm going to need to purge my >> answers>> of all insinuation that APL is rubbish. People will be >> so relieved! >>>> "It's about J and it doesn't rubbish APL...!" >>>> >>>> But I know what they're going to ask: what's with all these >>>> nouns and pronouns? >>>> >>>> I've asked on this list: "what's a pronoun"? I still don't >> know the >>>> answer (with my APL hat on, let me stress). I'm going to have >> to say: >>>> "it's only metalanguage." (...right: where's it formally >>>> defined?) "It >>>> isn't. The documenters want you to read their minds." (...ok, >>>> give me >>>> a clue.) "I can't. In two year's time you'll think it's all >> perfectly>> natural" (...meanwhile...?) >>>> >>>> Ian >>>> >>>> >>>> On Mon, Oct 25, 2010 at 3:39 PM, Roger >> Hui<[email protected]> wrote: >>>>> No, I don't mean "array or scalar", I meant "array". >>>>> Let me cite two sources: >>>>> >>>>> 0. Dyalog APL Language Reference/Variables/Arrays: - >>>>> A Dyalog APL data structure is called an array. ... An array >>>>> may have 0 or more axes. >>>>> >>>>> 1. ISO/IEC 13751-2001, ISO Standard on Extended APL, >>>>> Section 5.3.2: Scalar: An array whose rank is zero. >>>>> >>>>> As well, in practice, if a scalar in APL is if not an array, >>>>> then when you talk about APL you'd be constantly saying >>>>> "array or scalar" rather than just "array". (I was >>>>> once asked by non-mathematicians why 1 is not >>>>> a prime. After 5 seconds of thought I said, >>>>> "because it makes lots of statements simpler". >>>>> (As it is, you already have statements in math of the >>>>> sort "let n be an odd prime".)) >>>>> >>>>> In APL, if a "value" can only be an array, what word or >>>>> words would you use when you need to say "the x of >>>>> a phrase", when the phrase can be +/ or +/ 1 2 3 >>>>> or . or ¨? >>>>> >>>>> Reading your statements about "variable" in APL, >>>>> with descriptions of quad-nc, artificial restrictions on >>>>> reassignment, quad-ex, etc. etc., it strikes me that >>>>> in contrast the meanings of "noun" and "pronoun" >>>>> are simpler and more precise (less variable ...) than >>>>> in APL. Even more so in any APLs which do not >>>>> allow names be assigned to a function via ← . >>>>> (Then functions can only be named as a side effect >>>>> of ⎕fx or of an edit session.) One more thing: >>>>> Dyalog APL, which does allow sum←+/, does not >>>>> allow each←¨ . Explain that one. >>>>> >>>>> >>>>> >>>>> ----- Original Message ----- >>>>> From: Ian Clark<[email protected]> >>>>> Date: Monday, October 25, 2010 0:38 >>>>> Subject: Re: [Jgeneral] "J In A Day" --crits please >>>>> To: General forum<[email protected]> >>>>> >>>>>> Roger, >>>>>> >>>>>> I'd call sum a "variable" in APL if-and-only-if ([]NC 'sum') >>>>>> returns 2. >>>>>> >>>>>> In Dyalog APL (I don't have it installed on my Mac) I seem to >>>> recall>> you can indeed write: >>>>>> sum←+ >>>>>> but []NC 'sum' would afterwards return 3, telling me it's >>>>>> a function >>>>>> (...whatever else it might have been before). >>>>>> >>>>>> So... "what do you call a name in APL whose referent is a >>>> function?">> -- A function name. >>>>>> >>>>>> Moreover I think most APLs won't let you change "sum", say, >>>> from a >>>>>> variable name to a function name by reassigning it. Even if >>>> functional>> assignment is permitted. The statement (sum←+) >>>> causes an error >>>>>> if sum >>>>>> is already defined in the workspace as a variable, and you >> haven't>>>> freed-up the name 'sum' for reuse by localisation or []EX. >>>>>> >>>>>> I use "value" (...but only in an APL context, let me >>>> emphasise) to >>>>>> mean "something that can be assigned to a variable" (...and >>>> it still >>>>>> remains a variable). I think a lot of APLers would agree >> with that. >>>>>> It's a more restricted meaning of "value" than you imply in >>>> the J >>>>>> context, which it seems to me means anything acceptable to >>>> the right >>>>>> of a copula. Or, more precisely, any entity that is >> returned by >>>>>> evaluating a phrase which can validly stand to the right of a >>>> copula.>> >>>>>> You say that "noun" in J corresponds directly and exactly >>>> with "array" >>>>>> in APL. Was that a mistake... don't you mean "array or scalar"? >>>>>> (...commonly expressed as "vector or scalar" -- "array" not >>>>>> being a >>>>>> proper APL term, and [APL] "vector" not being restricted to >> 1-D >>>>>> arrays.) Surely you don't mean me to infer that 99 is not a noun >>>>>> in J >>>>>> because it is not an "array" in APL? >>>>>> >>>>>> I'm not interested in challenging Ken's appeal to his implicit >>>>>> understanding of English Grammar (which I deny is necessarily >>>>>> mine, or >>>>>> indeed anyone else's) to convey programming ideas. He's allowed >>>>>> to do >>>>>> that. I just want a precise enough notion of "noun/pronoun" >> -- >>>>>> as it >>>>>> applies to J -- so I can point to something in J code and >> say with >>>>>> confidence "that's a noun" or "that's a pronoun". >>>>>> >>>>>> Ian >>>>>> >>>>>> >>>>>> 2010/10/25 Roger Hui<[email protected]>: >>>>>>>> But Ken talks of "analogies", and seems to use the word "noun" >>>>>>>> to mean a value or quantity: the result of an expression, >>>> not the >>>>>>>> variable -- or named memory location -- it's stored in. What, >>>>>> in J, >>>>>>>> corresponds to an APL "variable"? >>>>>>> >>>>>>> "Noun" in J does not mean value. It corresponds >>>>>>> directly and exactly to "array" in APL. A value can >>>>>>> be a verb (function), for example, "the value of the >>>>>>> sentence +/ is a verb that does summation". >>>>>>> >>>>>>> Regarding your last question, It depends on how >>>>>>> "variable" is used in APL. If you say sum←+/ 2 3 4, >>>>>>> I think you'd call "sum" a variable. But if you say >>>>>>> sum←+/, is "sum" still a variable? If not, what is >>>>>>> the difference, and what do you call a name in APL >>>>>>> whose referent is a function? If yes, doesn't it >>>>>>> sound jarring to your ears? (It does to mine.) >>>>>>> >>>>>>> And, a question Ken used to ask: if sum←1 2 3, >>>>>>> what is variable about "sum"? >>>>>>> >>>>>>> Some APL texts also calls .5 and 1 2 3 and 'abc' >>>>>>> "variables, that is, used "variable" and "array" >>>>>>> as synonyms. Ken's question is even more pertinent >>>>>>> in those cases: If ever .5 has a different value >>>>>>> ("varied"), I expect to get system errors shortly >>>>>>> thereafter. >>>>>>> >>>>>>> There is a table in the dictionary section II. Grammar: >>>>>>> http://www.jsoftware.com/help/dictionary/dict2.htm >>>>>>> >>>>>>> PARTS of SPEECH >>>>>>> >>>>>>> 50 >> fahrenheit Nouns/Pronouns >>>>>>> + - * % bump Verbs/Proverbs >>>>>>> / \ Adverbs >>>>>>> & Conjunction >>>>>>> ( ) Punctuation >>>>>>> =: Copula >>>>>>> >>>>>>> >>>>>>> >>>>>>> ----- Original Message ----- >>>>>>> From: Ian Clark<[email protected]> >>>>>>> Date: Sunday, October 24, 2010 12:21 >>>>>>> Subject: [Jgeneral] "J In A Day" --crits please >>>>>>> To: General forum<[email protected]> >>>>>>> >>>>>>>> First draft of an article for eventual submission to VECTOR >>>>>> entitled>> "J In A Day". >>>>>>>> >>>>>>>> http://www.jsoftware.com/jwiki/JinaDay >>>>>>>> >>>>>>>> It is "work-in-progress". It represents an "alpha" offering, >>>>>> not a >>>>>>>> "release" or "publication". It's aimed squarely at the >>>> APLer who >>>>>>>> doesn't know any J. >>>>>>>> >>>>>>>> There won't be many such on this list. But right now I'm keen >>>>>> to get >>>>>>>> the J right. >>>>>>>> >>>>>>>> The prevalent message to APLers coming to J is: un-learn >>>> everything>> >> you know about APL (it's not >> helpful) and learn >>>> J from first >>>>>>>> principles. I think this erects an unnecessary barrier to the >>>>>>>> dwindling(?) band of APLers ignorant of J. >>>>>>>> >>>>>>>> Of course the barriers may be there anyway. I recall my first >>>>>> exposure>> to J aroused antipathy in me. I can't >> quite remember >>>>>> why. A Kuhnian >>>>>>>> paradigm-shift may be inescapable--or at least the need for >>>>>> one. The >>>>>>>> article deliberately avoids being starry-eyed so as not to >>>>>> raise the >>>>>>>> APLer's hackles. But this is not meant as provocation to the >>>>>> J-er. >>>>>>>> >>>>>>>> There's a fairly defiant "admonition" (as MoinMoin calls it) >>>>>> to J >>>>>>>> experts -- but don't be put off. I would really >> appreciate your >>>>>>>> comments. So get your anoraks on... ;) >>>>>>>> >>>>>>>> Of course, if an APL-er knowing absolutely no J were to work >>>>>> through>> it, and confirm (or deny) it was of use to >> them...>>>> that would >>>>>>>> get me >>>>>>>> on like 7-league boots. >>>>>>>> >>>>>>>> BTW I use the J terms "proverb" and "pronoun" in it. I >>>> need to >>>>>>>> know if >>>>>>>> I'm using them correctly. See my separate posting. >>>>>>>> >>>>>>>> Thanks, Brian, for the Iverson ref. From the horse's mouth, >>>>>> so to >>>>>>>> speak. But Ken talks of "analogies", and seems to use the >>>>>> word "noun" >>>>>>>> to mean a value or quantity: the result of an expression, >>>> not the >>>>>>>> variable -- or named memory location -- it's stored in. What, >>>>>> in J, >>>>>>>> corresponds to an APL "variable"? > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
