Many thanks for your kind words Dan. As in mathematics the person that
puts the last piece in place and starts the engine gets most of the
credit. Yet, other people contributed, particularly you, including (at
least indirectly)... Raul! Do not get me wrong though; I am very proud of
the "holy grail." :) I am re posting the fixed version here using another
pro-adverb (hg) because I use the Adv name often for another purpose:
o=. @:
e=. &.>
ar=. 5!:1@:<
(a0=. `'') (a1=. (@:[) ((<'&')`) (`:6)) (a2=. (`(<(":0);_)) (`:6))
av=. ((ar'a0')`) (`(ar'a1')) (`(ar'a2') ) (`:6)
NB. Adverbing a monadic verb (adv)
assert 1 4 9 -: 1 2 3 *: av
aw=. < o ((0;1;0)&{::) NB. Fetching the atomic representation
a3=. (@: (aw f.)) ('av'f.)
a4=. "_
a5=. `:6
a6=. ((( ar'a4') ; ] ; ( ar'a3')"_) ('av'f.)) (`:6)
hg=. `((ar'a6')`(ar'a5')) (`:6)
assert 1 4 9 -: 1 2 3 ((<'*:') ; ] ) hg
assert 6 -: * (< , ((<'/')"_)) hg 1 2 3
assert 0 1 3 -: (*:`(+/\)) (0&{ , (<'-') , 1&{)@:(('';1)&{::) hg 1 2 3
erase'a0 a1 a2 a3 a4 a5 a6 ar av aw'
Feel free to rename, modify, explain, etc. as you please. You might also
like to make the script suitable for loading with the verb load. (I am
allergic to run scripts within an unfaithful explicit environment because
one can get confused sometimes.) I wrote the "holy grail" in a hurry and I
would not be surprised if some bugs arise but so far, so good.
You might like to know that recently I found, half buried in the archives,
my original Turing machine post [0]. There is also a recent version in the
Rosetta code site.
[0] Jforum: A Tacit Implementation of a Turing Machine
http://www.jsoftware.com/pipermail/general/1999-December/002736.html
On Thu, Mar 17, 2016 at 11:22 PM, Dan Bron <[email protected]> wrote:
> Pepe wrote:
> > Let us add another twist, courtesy of David Lambert, to the Exercise 1:
>
>
> All these puzzles are interesting, but ever since you posted the “holy
> grail”, the “write a tacit adverb to do X” challenges have been reduced (in
> principle) to “write a tacit verb to do X”, and given you sent me, in
> something like 2002, a complete implementation of a Turing Machine as a
> tacit verb, the exercises seem … superfluous.
>
> In other words, it can all be done, because you have done all of it. In a
> very literal sense.
>
> The upside, however, is I have never read one of your posts and not
> learned something not only new, but intriguing. If I were given to envy, I
> might have experienced that, as well. Good thing the only sentiment I feel
> for my fellow man is admiration ;)
>
> That said, if Thomas comes through with an interpreter which re-introduces
> (some of) the F Trains table, new challenges (in terms of brevity and
> algebraic reduction) will open up to us. If I were given to
> competitiveness, I might perceive that as a kind of perverse motivation.
>
> I’m already dusting off my running shoes.
>
> -Dan
>
> * In general, I have been, historically, lax about backups.
>
> In general, I am not bothered, because death is inevitable and possessions
> are but albatrosses about our necks, but a few losses have made me regret
> this specific foible.
>
> All the lost treasures which I was given by the luminaries of J, early in
> my career, before I was in a position to truly appreciate them, including
> your Turing Machine, personal correspondence from Ken, private guidance by
> Henry Rich, a utilities file presented to me by Kirk Iverson, etc, number
> among these regrets.
>
> Ah well, youth is not known for its gratitude, is it?
>
>
>
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>
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