That's simpler than what I was thinking of. And that does satisfy my concept of tacit programming, though I think I remember hearing rumblings from other people that this kind of thing is not tacit. (Actually, if tacit means "no use of names" then the 3 :'0 :0' definition would also be tacit.)
Thanks, -- Raul On Fri, Feb 12, 2016 at 6:18 PM, Jose Mario Quintana <[email protected]> wrote: > getnoun=. ".@:('0 : 0'"_) > > $getnoun'' > 1 2 3 > 4 5 6 > ) > 12 > > > On Fri, Feb 12, 2016 at 2:41 PM, Raul Miller <[email protected]> wrote: > >> Wrapping 0 :0 in an explicit verb should be possible: >> >> getnoun=:3 :'0 :0' >> $getnoun'' >> 1 2 3 >> 4 5 6 >> ) >> 12 >> >> It's also possible to do this tacitly, but yeah, doing it tacitly such >> that it triggers when a verb is executed would be tricky (possible, >> but overly verbose to accomplish). Also, not sure if that would have >> any uses... >> >> Personally, I rarely even bother using the predefined (noun define) >> cover for this. The raw 0 :0 form is actually rather convenient. >> >> Thanks, >> >> -- >> Raul >> >> >> On Fri, Feb 12, 2016 at 2:03 PM, Matthew Baulch <[email protected]> >> wrote: >> > Ok. That explains things well. So the the line(s) containing : behave >> just >> > as if : is an everyday conjunction. It's the lines AFTER : that are >> treated >> > specially. >> > >> > I suppose that's quite a clear design. I'll re-read the documentation. >> Like >> > you say, once I know what's going on, these subtle points are more likely >> > to stand out. >> > >> > ". does indeed have unlimited potential—over the domain of character >> arrays >> > anyway. I'm trying to wrap this construction in a verb so I can obtain >> > these multi-line definitions without explicitly calling ". . Just for >> > feelings of purity. It doesn't seem like this can be accomplished >> tacitly. >> > I'm starting to think that 0:0 has to appear in each definition, and so >> > defining such a verb may not be possible. Oh well. >> > >> > Thanks. : makes sense now. >> > On 12 Feb 2016 2:11 pm, "Henry Rich" <[email protected]> wrote: >> > >> >> > Forgive me if I'm wrong, but I don't see a discussion of 'expressions >> to >> >> the >> >> > right of zero' (such as '-.LF' in '0 : 0 -. LF') >> >> > in either of your links. >> >> >> >> No. But that isn't surprising when you understand what's going on. >> >> >> >> 0 : 0 creates a noun. >> >> >> >> Because conjunctions are executed before verbs, >> >> >> >> 0 : 0 -. LF >> >> >> >> is the same as >> >> >> >> (0 : 0) -. LF >> >> >> >> (0 : 0) creates a noun that can be used just as any other noun is used. >> >> You can add to it, subtract from it, execute it... The (-. LF) has >> nothing >> >> to do with the execution of (:). What I'm saying is, if you are OK with >> >> something like >> >> >> >> ".;._2 (0 : 0) >> >> >> >> [which feeds the result of (0 : 0) into a verb], you should ipso facto >> be >> >> OK with >> >> >> >> (0 : 0) -. LF >> >> >> >> which also feeds that result into a verb, just from the left this time. >> >> >> >> The (:) in (0 : 0) is executed WHEN (:) IS EXECUTED, i. e. at the >> >> appropriate time during the parse [see NuVoc for explanations]. After >> (:) >> >> has read its fill, execution of the sentence continues. So, you can have >> >> >> >> (0 : 0) ,&(".;._2) (0 : 0) >> >> >> >> 1 2 3 >> >> >> >> ) >> >> >> >> 10 20 30 >> >> >> >> 40 50 60 >> >> >> >> 70 80 90 >> >> >> >> ) >> >> >> >> 10 20 30 >> >> >> >> 40 50 60 >> >> >> >> 70 80 90 >> >> >> >> 1 2 3 >> >> >> >> >> >> Two (0 : 0) in one sentence [the parentheses are not required]! and >> >> executed right-to-left. >> >> >> >> >> >> >> >> (".) has unlimited potential, but often is put to mundane use. When I >> was >> >> starting with J I felt a frisson of daring when I used it, but now it's >> >> just another verb to me. >> >> >> >> >> >> Henry Rich >> >> >> >> >> >> >> >> >> >>> I'd welcome any correction. >> >>> >> >>> Cheers. >> >>> It's pretty well explained at >> >>> >> >>> http://code.jsoftware.com/wiki/Vocabulary/NounExplicitDefinition >> >>> >> >>> The question is, How would you know to read that? Suggestions >> welcomed. >> >>> >> >>> When you say "expression following the 0", I'm not sure which 0 you >> mean. >> >>> >> >>> : is the all-purpose entity creator; the left 0 says 'create a noun', >> and >> >>> the right >> >>> 0 says 'make that noun from the upcoming lines of input'. >> >>> >> >>> Full details are spelled out in several pages starting at >> >>> http://code.jsoftware.com/wiki/Vocabulary/cor >> >>> >> >>> Henry Rich >> >>> >> >>> >> >>> On 2/11/2016 12:55 AM, Matthew Baulch wrote: >> >>> >> >>> Thanks everyone. This (let's say) creative use of 0 : 0 makes sense to >> me >> >>>> now. I wonder if it's an accidental consequence of the implementation >> >>>> that >> >>>> allows an expression following the 0, or whether it's a deliberate >> design >> >>>> decision. Either way, it makes sense to have it documented. Can't see >> it >> >>>> in >> >>>> NuVoc or the Dictionary. Of course, I may have overlooked it. >> >>>> >> >>>> Honestly, to obtain something simple like multi-line noun >> definitions, ". >> >>>> does seem like quite a heavy-handed tool. It does work however, so I >> >>>> probably shouldn't grumble. >> >>>> >> >>>> Cheers. >> >>>> >> >>>> On Wed, Feb 10, 2016 at 10:29 PM, Matthew Baulch < >> [email protected]> >> >>>> wrote: >> >>>> >> >>>> Looking at this more closely now. I'm a bit puzzled about the use of >> -. >> >>>> >> >>>>> here. Obviously this is used here in dyadic form. In x -. LF the LF >> >>>>> characters are, of course, removed from x. What is the x here? I have >> >>>>> seen >> >>>>> that it works--not doubting that. Just trying to work out how. Sorry. >> >>>>> There's probably something obvious I've missed. >> >>>>> >> >>>>> On Wed, Feb 10, 2016 at 12:52 AM, Raul Miller <[email protected] >> > >> >>>>> wrote: >> >>>>> >> >>>>> If you do not have good names for partial calculations, that might be >> >>>>> >> >>>>>> a sign that you need to think a bit more about the abstractions you >> >>>>>> are using. It can be difficult for other people to read if you don't >> >>>>>> make sufficient effort to label your abstractions. >> >>>>>> >> >>>>>> Also, I would note that your 'c0' is not a combinator, as you are >> not >> >>>>>> using its dyadic definition. So you might want to use a different >> name >> >>>>>> for that one. Perhaps: >> >>>>>> >> >>>>>> v0=:c0 >> >>>>>> >> >>>>>> That said, if you really want to execute really long lines, you can >> do >> >>>>>> that using ". 0 :0-.LF and indented text. (You need the indentation >> >>>>>> because line feeds will not separate words here.) >> >>>>>> >> >>>>>> For example: >> >>>>>> >> >>>>>> myStruct=: ". 0 :0-.LF >> >>>>>> v0 p0 c1 p1 c2 p2 c3 p3 c4 p4 c5 p5 c6 p6 c7 p7 c8 p8 c9 p9 >> >>>>>> c10 p10 c11 p11 c12 p12 c13 p13 c14 p14 c15 p15 c16 p16 c17 >> >>>>>> p17 c18 p18 c19 p19 c20 p20 c21 p21 c22 p22 c23 p23 c24 p24 >> >>>>>> c25 p25 c26 p26 c27 p27 c28 p28 c29 p29 c30 p30 >> >>>>>> ) >> >>>>>> >> >>>>>> I hope this helps, >> >>>>>> >> >>>>>> -- >> >>>>>> Raul >> >>>>>> >> >>>>>> On Tue, Feb 9, 2016 at 4:59 AM, Matthew Baulch < >> [email protected]> >> >>>>>> wrote: >> >>>>>> >> >>>>>> Suppose I wish to construct a complex, non-regular deeply nested >> >>>>>>> >> >>>>>>> structure: >> >>>>>> >> >>>>>> to model some inherently non-linear system. A natural approach (for >> me, >> >>>>>>> anyhow) is to construct a library of combinators, or a domain >> specific >> >>>>>>> language, with which to specify the (boxed) structure. >> >>>>>>> >> >>>>>>> J rises easily to the task, and before long I'm looking at long >> >>>>>>> function >> >>>>>>> trains of the form >> >>>>>>> >> >>>>>>> myStruct =: c0 p0 c1 p1 c2 p2 ... cN pN >> >>>>>>> >> >>>>>>> where the ci are (combinator) verbs, and the pj are (parameter) >> nouns. >> >>>>>>> Nice. Easy. >> >>>>>>> >> >>>>>>> Only trouble is, N may be large and J prefers such statements to >> sit >> >>>>>>> on >> >>>>>>> >> >>>>>>> a >> >>>>>> >> >>>>>> single line. Correct? I can split my definition: >> >>>>>>> >> >>>>>>> msPartA =. ..... >> >>>>>>> msPartB =. ..... >> >>>>>>> ..... >> >>>>>>> msPartX =. ..... >> >>>>>>> myStruct =: msPartA msPartB .... msPartX >> >>>>>>> >> >>>>>>> though this feels awkward. The most obvious issue is that the >> PartA, >> >>>>>>> >> >>>>>>> ..., >> >>>>>> >> >>>>>> PartX are distracting; unless of course I can find a natural way of >> >>>>>>> splitting and naming them. Ideally, the parts should be as close >> to a >> >>>>>>> comfortable line width as possible. Again, awkward. If myStruct1 >> and >> >>>>>>> myStruct2 have the same partitioning scheme but myStruct2 (for >> >>>>>>> >> >>>>>>> instance) is >> >>>>>> >> >>>>>> much larger than myStruct1, there will be many sparsely, or many >> >>>>>>> overpopulated lines. Awkward too. >> >>>>>>> >> >>>>>>> I love J. It handles complex regular data so elegantly. How can I >> >>>>>>> bring >> >>>>>>> similar elegance to irregular data? Can my combinators be rescued, >> or >> >>>>>>> should I use another approach? >> >>>>>>> >> ---------------------------------------------------------------------- >> >>>>>>> For information about J forums see >> >>>>>>> http://www.jsoftware.com/forums.htm >> >>>>>>> >> >>>>>>> >> ---------------------------------------------------------------------- >> >>>>>> For information about J forums see >> http://www.jsoftware.com/forums.htm >> >>>>>> >> >>>>>> >> >>>>>> >> ---------------------------------------------------------------------- >> >>>>> >> >>>> For information about J forums see >> http://www.jsoftware.com/forums.htm >> >>>> >> >>>> ---------------------------------------------------------------------- >> >>> For information about J forums see http://www.jsoftware.com/forums.htm >> >>> ---------------------------------------------------------------------- >> >>> For information about J forums see http://www.jsoftware.com/forums.htm >> >>> >> >> >> >> ---------------------------------------------------------------------- >> >> For information about J forums see http://www.jsoftware.com/forums.htm >> > ---------------------------------------------------------------------- >> > For information about J forums see http://www.jsoftware.com/forums.htm >> ---------------------------------------------------------------------- >> For information about J forums see http://www.jsoftware.com/forums.htm >> > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
