[Jprogramming] How to make this conjunction tacit

Thu Oct 10 12:11:56 UTC 2013

creating a conjunction tacitly is hacky or impossible.  currently the train (a c) is a syntax error.  What I'd suggest instead is that it be treated as a conjunction.   So the explicit (2 : ']`u at .v') could be written as (]`@.)

If 1 conjunction is present in what whould otherwise be an adverb train, then the train should be a conjunction whose right v argument will be lifted into the train and placed to the right of the individual conjunction inside the train

More generally, an adverb train that includes a conjunction is a conjunction that you may bind as any other conjunction (u (a a c)) becomes the adverb ((u a a) c), and (a a c)v becomes 'a a c v', and (c a)v would be the adverb '(c v) a'

the above was a refinement to this musing:

What I would suggest instead is that @: be a "super conjunction".  If it was deemed that a tacit version of: 'u a c v' is worthwhile, then (a c @:) would do it.  (c @:) would make the adverbe (c v), and (@: c) would make the adverb (u c).  One actual usefulness for this might be: (c1 @:) (c2 @:) v1 v2 might turn into (c1 v1) (c2 v2) or just (c1 v1) (c1 v1).
>
> An alternative to @: as "super conjunction" would be [: .  ([: c a a a a) and (a a a a c [:)

----- Original Message -----
From: Raul Miller <rauldmiller at gmail.com>
To: Programming forum <programming at jsoftware.com>
Cc: 
Sent: Thursday, October 10, 2013 12:14:48 AM
Subject: Re: [Jprogramming] How to make this conjunction tacit

I do not have any reasonable idea what you are talking about here.

Can you give some examples?

Thanks,

-- 
Raul

On Wed, Oct 9, 2013 at 9:48 PM, Pascal Jasmin <godspiral2000 at yahoo.ca> wrote:
> A bit more on the super- conjunction idea, it turns out that it is not quite needed.  Instead,
>
> (a a c a) should be a conjunction interpreted as (a a (c (v a))) where v is the right hand verb.  The total train would be: '(u a a) c (v a)'
>
> it could also be possible to understand (c1 c2) as (u c1) (c2 v), and if so then
>
> (a a c1 a c2 a) would be: '(u a a c1) a (c2 v a)'
>
> There could not be more than 2 conjunctions in an adverb train without the super conjunction ([:  or ]:) idea, but 2 is a big increase over 0.
>
>
> ----- Original Message -----
> From: Pascal Jasmin <godspiral2000 at yahoo.ca>
> To: "programming at jsoftware.com" <programming at jsoftware.com>
> Cc:
> Sent: Monday, October 7, 2013 5:10:47 PM
> Subject: Re: [Jprogramming] How to make this conjunction tacit
>
>
>
> Regarding the archeology archive, not all of those seem like good ideas.  What I would suggest instead is that @: be a "super conjunction".  If it was deemed that a tacit version of: 'u a c v' is worthwhile, then (a c @:) would do it.  (c @:) would make the adverbe (c v), and (@: c) would make the adverb (u c).  One actual usefulness for this might be: (c1 @:) (c2 @:) v1 v2 might turn into (c1 v1) (c2 v2) or just (c1 v1) (c1 v1).
>
> An alternative to @: as "super conjunction" would be [: .  ([: c a a a a) and (a a a a c [:)
>
>
> ----- Original Message -----
> From: Dan Bron <j at bron.us>
> To: programming at jsoftware.com
> Cc:
> Sent: Monday, October 7, 2013 4:23:36 PM
> Subject: Re: [Jprogramming] How to make this conjunction tacit
>
> Pascal asked:
>>  How to make this conjunction tacit
>>  coerce =: 2 : ']`u at .v'
>
>
>        coerce =: ^:
>
>        < coerce (0=L.) 2
>     +-+
>     |2|
>     +-+
>        < coerce (0=L.) <2
>     +-+
>     |2|
>     +-+
>
> This particular coercion is also available as a ready-made utility in the standard library as "boxopen" and its cousin "boxxopen" (which is the same except it leaves empty arguments unboxed).
>
> Note that it was trivial to write coerce tacitly because we have a primitive conjunction that fits the bill (obviating the need for a user-defined conjunction). In the general case, it is not possible to write tacit conjunctions.  To understand why, read through section §II.F in the DoJ, and note that while there are rules for producing tacit verbs (e.g. "fork" for +/ # %) and adverbs (e.g. "adverb train" for /\) there are no rules which produce conjunctions.
>
> That said, it may be possible to synthesize or simulate a tacit conjunction through a series of tacit adverbs, e.g.:
>
>        shanghai=.(`]) (`(;:'`@.')) (@.(0 2 1 3))
>
>        (0=L.) < yyy
>
>     <`]@.(0 = L.)
>
> But these tend to be very convoluted, difficult to both write and understand, and will commonly involve some degree of quoted code anyway, so it is just as well (actually, better) to write them explicitly in the first place.
>
> One more note: depending on your needs, you might prefer (0<L.) to (0=L.) . The former boxes only unboxed nouns; the latter boxes unboxed nouns as well as anything with a depth _greater_ than one (e.g. try <<2, <<<2, etc).
>
> -Dan
>
> PS: In the good old days, §II.F contained a long and rich table of interpretations for various trains (i.e. sequences of words/word-classes) which made it possible, among other things, to write conjunctions tacitly.
>
> Again, these turned out to be convoluted and difficult, and consequently infrequently used in practice.  In turn, it was decided that the cost of supporting the trains table (i.e. scanning all the possibilities for every single sentence of J executed) was worth less than they were worth, so the decision was made to remove it and simplify both the language and the interpreter.
>
> That happened in J5, I believe.  Anyway, for those interested in archaeology, or simply in what the language used to permit, check out the old trains table available at [1] and reproduced below.  The rows having product="conj" were all the ways a J programmer could express conjunctions tacitly.
>
> [1] Cache of J4 Dictionary §II.F:
>    http://www.cs.trinity.edu/About/The_Courses/cs2322/jdoc/dict/dictf.htm
>
> Train      Product  Interpretation
> --------   -------  ---------------------
> N0 V1 N2   noun     x V1 y
> V0 V1 V2   verb     (x V0 y) V1 (x V2 y)
> V0 V1 C2   conj     V0 V1 (x C2 y)
> A0 V1 V2   adv      (x A0) V1 V2
> C0 V1 V2   conj     (x C0 y) V1 V2
> C0 V1 C2   conj     (x C0 y) V1 (x C2 y)
> A0 A1 V2   conj     (x A0) (y A1) V2
> A0 A1 A2   adv      ((x A0) A1) A2
> C0 A1 A2   conj     ((x C0 y) A1) A2
> N0 C1 N2   verb     x (N0 C1 N2) y
> N0 C1 V2   verb     x (N0 C1 V2) y
> N0 C1 A2   adv      N0 C1 (x A2)
> N0 C1 C2   conj     N0 C1 (x C2 y)
> V0 C1 N2   verb     x (V0 C1 N2) y
> V0 C1 V2   verb     x (V0 C1 V2) y
> V0 C1 A2   adv      V0 C1 (x A2)
> V0 C1 C2   conj     V0 C1 (x C2 y)
> A0 C1 N2   adv      (x A0) C1 N2
> A0 C1 V2   adv      (x A0) C1 V2
> A0 C1 A2   conj     (x A0) C1 (y A2)
> A0 C1 C2   conj     (x A0) C1 (x C2 y)
> C0 C1 N2   conj     (x C0 y) C1 N2
> C0 C1 V2   conj     (x C0 y) C1 V2
> C0 C1 A2   conj     (x C0 y) C1 (y A2)
> C0 C1 C2   conj     (x C0 y) C1 (x C2 y)
> N0 A1      verb     x (N0 A1) y
> N0 C1      adv      N0 C1 x
> V0 N1      noun     V0 y
> V0 V1      verb     x (or y) V0 V1 y
> V0 A1      verb     x (V0 A1) y
> V0 C1      adv      V0 C1 x
> A0 V1      adv      (x A0) V1
> A0 A1      adv      (x A0) A1
> A0 C1      adv      (x A0) C1 x
> C0 N1      adv      x C0 N1
> C0 V1      adv      x C0 V1
> C0 A1      conj     (x C0 y) A1
>
>
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