(And yes, this would cause trouble for corecursion; but I think that's fine.
There are however tricks with binders that could be used to work around it if
desirable.)
On Sun, 22 Jan 2023, Elijah Stone wrote:
The way I was imagining it, the effect would be that verbs in lexical scope
would be eagerly bound modulo definition order. There would be no
complication added to the object model.
On Sun, 22 Jan 2023, Raul Miller wrote:
A problem with closures is that a complete implementation might
require a radical change in J's memory management mechanisms (and also
introduce difficulties for mechanisms like gerunds or 5!:n).
Currently, J's arrays are trees, and verbs, adverbs and conjunctions
are arrays in this sense.
With closures, verbs might become digraphs because J allows undefined
names in tacit verb definitions.
To resolve these issues, closures might only be allowed to preserve
noun values. But introducing some sort of "complete local copy" aka
"snapshot" mechanism for verbs adverbs and conjunctions might also be
viable?
Thanks,
--
Raul
On Tue, Jan 17, 2023 at 7:01 PM Elijah Stone <elro...@elronnd.net> wrote:
I suggest:
[x] u &:: (k;v;k;v...) y
Will evaluate u with bindings kvkv... (raveled) active. Should work for
both
explicit and tacit. Implementation is allowed to coalesce; e.g., u &::
(k;v)
&:: (k;v) `'' may be rendered u &:: (k;v;k;v), deduplicated, &c.
Substitution also ok; eg (f%#) &:: ('f';+/`'') becomes +/%#.
I would like for verbs defined inside of explicit verbs to be implicitly
closed; this is obviously a compat break, but.
On Tue, 17 Jan 2023, Elijah Stone wrote:
> I don't love the proposal, as I think a conception of verbs as first
class
> should involve _less_ hackery with representations, not more. But I
don't
> feel that strongly either way.
>
> More fruitful, IMO, would be to work out how to add closures, as I think
> there
> is a more urgent need for that (u./v. is a band-aid). Perhaps taking
> inspiration from kernel (but skipping the mutation!).
>
> On Mon, 16 Jan 2023, Henry Rich wrote:
>
>> I have never understood the zeal for having verbs return verbs, but it
>> must be real if some are willing to use dangerous backdoor hacks into
JE
>> to achieve it. ARs make it possible to pass verbs around, but
executing
>> them requires dropping into explicit code. To remedy this, I offer a
>> proposal, backward compatible with older J:
>>
>> 1. (". y) and Apply (x 128!:2 y) to be modified so that if the result
of
>> execution is not a noun, it is replaced by its AR (instead of '' as
>> previously).
>>
>> 2. (". y) and Apply to be modified so that if y (for ".) or x (for
>> Apply) is boxed, the sentence is executed as usual except that each box
>> is converted using (box 5!:0) before being put onto the execution
stack.
>>
>> The idea is that you can execute (".
>> expr-producing-AR,exp-producing-AR,...) without having to get any
>> modifiers involved.
>>
>> Sentence execution can produce ARs, and can take ARs created by verbs
to
>> represent verbs and modifiers. That sounds pretty classy to me, but I
>> don't know whether it's first-class.
>>
>> Henry Rich
>>
>>
>>
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>>
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