I think one issue is that interpreting 5!:2 results as trains can
result in ambiguities.

   ar=:1 :'5!:1<''u'''
   br=:1 :'5!:2<''u'''
   F=: ,&(3 ar)
   F
,&(<(,'0');3)
   F f. br`:6
,&3

Or, generally speaking, nouns in 5!:2 results are not intended for use
in trains.

   G=: +&3
   G f. br`:6
|domain error

I hope this helps,

-- 
Raul

On Thu, Mar 12, 2020 at 12:20 AM Henry Rich <henryhr...@gmail.com> wrote:
>
> Change?  We have been discussing whether certain forms are valid.  The
> spec, Ye Dic, is silent and we are filling it in.
>
> Jsoftware's policy has been to leave the JE as it is in some cases where
> it accepts forms that are not valid according to the language
> definition.  This is from indolence more than benevolence, and a
> programmer would be unwise to rely on its continuance.  If I can save
> one mispredicted branch by disallowing an invalid form, I will.
>
> Here Pepe has noted some forms that the interpreter accepts.  I think
> they are not legal.  Use them at your peril.
>
> FWIW, I would not remove support for these forms without consulting the
> /ulama/.  They are in a gray area, unlike, say, verbs that return
> non-noun results, which I feel no commitment for.
>
> Henry Rich
>
>
>
> On 3/12/2020 12:00 AM, Devon McCormick wrote:
> > Would this change be likely to break existing code?
> >
> > On Wed, Mar 11, 2020 at 8:58 PM Henry Rich <henryhr...@gmail.com> wrote:
> >
> >> I would object to
> >>
> >>    ((<'"') ,~ (<;:'u@:v-v@:u')) (`:6)
> >>
> >> because the long sequence of ARs is not a valid AR.  This seems like an
> >> interpreter artifact.
> >>
> >> The result of 5!:2 is not germane here, as it is not an AR.  Your
> >> examples using it also seem to be interpreter artifacts to me.
> >>
> >> Henry Rich
> >>
> >> On 3/11/2020 8:22 PM, Jose Mario Quintana wrote:
> >>>> Of course the fact that m@.n allows certain forms does not imply that
> >>>> m@.v would support similar forms.
> >>> Of course.
> >>>
> >>>> I don't see anything to object to here.
> >>> Great!  This means tacit adverbs functioning as parameterized macros are,
> >>> or might be eventually, legitimized.
> >>>>                                            There are gerunds and adverbs,
> >>>> producing trains that evaluate properly.
> >>> Right, the trains evaluate properly; even though the list (;:'@:-"')
> >>> includes ARs of conjunctions (it is not my intention at all to argue
> >> with a
> >>> /mufti/ of J, I am just accentuating).
> >>>
> >>>> By The Wise I mean the /ulama/ of J (neminem nominabo, genus hominum
> >>>> significasse contentus)  You know who you are.
> >>> Train (`:6) can also evaluate properly forms associated with the
> >>> corresponding agenda (m@.n) evaluation, mutatis mutandis; exempli
> >> gratia,
> >>>      ((<'"') ,~ (<;:'u@:v-v@:u'))
> >>> ┌─────────────────┬─┐
> >>> │┌─┬──┬─┬─┬─┬──┬─┐│"│
> >>> ││u│@:│v│-│v│@:│u││ │
> >>> │└─┴──┴─┴─┴─┴──┴─┘│ │
> >>> └─────────────────┴─┘
> >>>
> >>>      ((<'"') ,~ (<;:'u@:v-v@:u')) (`:6)
> >>> (u@:v - v@:u)"
> >>>
> >>> Do the /ulama/ of J (et alli) disapprove?
> >>>
> >>> By the way, some boxed representations belong to this class of forms,
> >>>
> >>>      t=. (u@:v - v@:u)"
> >>>
> >>>      (5!:2<'t')
> >>> ┌─────────────────────┬─┐
> >>> │┌────────┬─┬────────┐│"│
> >>> ││┌─┬──┬─┐│-│┌─┬──┬─┐││ │
> >>> │││u│@:│v││ ││v│@:│u│││ │
> >>> ││└─┴──┴─┘│ │└─┴──┴─┘││ │
> >>> │└────────┴─┴────────┘│ │
> >>> └─────────────────────┴─┘
> >>>      (5!:2<'t') (`:6)
> >>> (u@:v - v@:u)"
> >>>
> >>> but not all of them,
> >>>
> >>>      t=. "1
> >>>
> >>>      (5!:2<'t')
> >>> ┌─┬─┐
> >>> │"│1│
> >>> └─┴─┘
> >>>
> >>>      (5!:2<'t') (`:6)
> >>> |domain error
> >>> |   (5!:2<'t')    (`:6)
> >>>
> >>> The issue here is the missing (in the evaluation sense) AR of 1,
> >>>
> >>>      (<,'"'),<<(,'0');1
> >>> ┌─┬───────┐
> >>> │"│┌─────┐│
> >>> │ ││┌─┬─┐││
> >>> │ │││0│1│││
> >>> │ ││└─┴─┘││
> >>> │ │└─────┘│
> >>> └─┴───────┘
> >>>      ((<,'"'),<<(,'0');1) (`:6)
> >>> "1
> >>>
> >>>
> >>> On Tue, Mar 10, 2020 at 11:49 PM Henry Rich <henryhr...@gmail.com>
> >> wrote:
> >>>> I don't see anything to object to here.  There are gerunds and adverbs,
> >>>> producing trains that evaluate properly.
> >>>>
> >>>>
> >>>> By The Wise I mean the /ulama/ of J (neminem nominabo, genus hominum
> >>>> significasse contentus)  You know who you are.
> >>>>
> >>>> Henry Rich
> >>>>
> >>>> On 3/10/2020 11:34 PM, Jose Mario Quintana wrote:
> >>>>>> I don't think it's illegal.  The spec (Ye Dic, here) is incomplete.
> >> It
> >>>>> That is good to know.
> >>>>>
> >>>>>> I don't see anything bad coming from executing a train containing
> >>>>>> non-verbs; so I would vote to expand the spec to include all trains.
> >>>>> I do not see anything bag coming either, on the contrary.
> >>>>>
> >>>>>> There would need to be discussion among The Wise before any such
> >>> change.
> >>>>> May I offer some food for thought to The Wise?
> >>>>>
> >>>>> I would expect that whatever is decided regarding the legality in J
> >>> about
> >>>>> the train's (`:6) arguments would, or should, affect its capable
> >>> relative,
> >>>>> agenda (@.), specifically the m@.n form; for instance, do The Wise, or
> >>> you,
> >>>>> in particular, think that the following sentences, supported by j901,
> >>> are
> >>>>> legal or illegal in J?
> >>>>>
> >>>>>       a=. (`(;:'@:-"'))(@.(4 ;~ (<0 2 1 3 1 2 0)))
> >>>>>
> >>>>>       u`v a
> >>>>> (u@:v - v@:u)"
> >>>>>
> >>>>>       _1 *:`(+/) a i. 2 3 4
> >>>>>      64  118  184  262
> >>>>> 1504 1702 1912 2134
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> On Tue, Mar 10, 2020 at 10:09 AM Henry Rich <henryhr...@gmail.com>
> >>> wrote:
> >>>>>> I don't think it's illegal.  The spec (Ye Dic, here) is incomplete.
> >> It
> >>>>>> says what will be done if there is a verb train but is silent about
> >>>>>> other trains.
> >>>>>>
> >>>>>> What the implementation does is accept any train and evaluate it.
> >>>>>> Thinking about it I don't see anything else you could do with a train;
> >>> &
> >>>>>> I don't see anything bad coming from executing a train containing
> >>>>>> non-verbs; so I would vote to expand the spec to include all trains.
> >>>>>>
> >>>>>> There would need to be discussion among The Wise before any such
> >>> change.
> >>>>>> Henry Rich
> >>>>>>
> >>>>>> On 3/9/2020 11:36 PM, Jose Mario Quintana wrote:
> >>>>>>> Henry wrote:
> >>>>>>>
> >>>>>>>> Ye Dic mentions only verb trains under `: .
> >>>>>>> Therefore, the sentence ((<,'"') ` (an 1) (`:6)) is illegal in J
> >>>>> because "1
> >>>>>>> is not a train of verbs (even if it is supported by j).  Correct?
> >>> (This
> >>>>> is
> >>>>>>> not a rhetorical question.)
> >>>>>>>
> >>>>>> --
> >>>>>> This email has been checked for viruses by AVG.
> >>>>>> https://www.avg.com
> >>>>>> ----------------------------------------------------------------------
> >>>>>> For information about J forums see
> >> http://www.jsoftware.com/forums.htm
> >>>>> ----------------------------------------------------------------------
> >>>>> For information about J forums see http://www.jsoftware.com/forums.htm
> >>>> --
> >>>> This email has been checked for viruses by AVG.
> >>>> https://www.avg.com
> >>>>
> >>>> ----------------------------------------------------------------------
> >>>> For information about J forums see http://www.jsoftware.com/forums.htm
> >>> ----------------------------------------------------------------------
> >>> For information about J forums see http://www.jsoftware.com/forums.htm
> >>
> >> --
> >> This email has been checked for viruses by AVG.
> >> https://www.avg.com
> >>
> >> ----------------------------------------------------------------------
> >> For information about J forums see http://www.jsoftware.com/forums.htm
> >>
> >
>
>
> --
> This email has been checked for viruses by AVG.
> https://www.avg.com
>
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm

Reply via email to