That's excellent. I would have noticed that immediately. It seems highly likely that others will easily find it too.
Multi-line definitions aside, example 27 (and the notes) serve to further illustrate how ':' works. A worthwhile exercise in my view. Thanks. On 13 Feb 2016 9:25 am, "Henry Rich" <[email protected]> wrote: > I have added to > > http://code.jsoftware.com/wiki/Vocabulary/cor > > especially notes 1, 2, and 12 and new example 27 at the end. See if this > would have helped. > > Henry Rich > > On 2/12/2016 2:03 PM, Matthew Baulch 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
