Hi all !

I think my blog post describes my view:
https://erlhelinfotech.wordpress.com/2016/08/01/jwithatwist-or-tacit-j/
It is in no way exhaustive in terms of problems  I find in tacit J, but I think it was more than enough for taking the decision.
"The tacit J syntax is a total mess of utter complexity."
"As you can see the choice could not be easier and I have chosen the modified explicit J syntax for JWithATwist."

Cheers,
Erling

On 2017-09-29 01:46, Ric Sherlock wrote:
Hi Erling,
Just want to suggest that statements like "we recognized tacit J is not
useful" seem a little premature unless "we" is the royal "we" i.e. "I".

Even then I suspect a more accurate statement would be "I don't see the
benefits of tacit J".

So far my understanding of your position is that you find that hooks and
forks are hard to parse and so want to make the syntax more linear while
retaining the benefits of not explicitly naming arguments in verbs. Please
feel free to correct me if I've misunderstood.

I had a brief read of your blog, on the matter and so far am not convinced
that this proposal provides more readable code in all or even many cases. I
agree that long tacit expressions can be hard to parse - I think this is
true of any long sentences. I think there are some expressions that are
very much simplified by the use of forks and hooks. I also agree that tacit
expressions can become unwieldy when dealing with more than 2 arguments.
Currently I favour a mix of tacit and explicit forms where they best fit. I
think I'd need to see a lot more examples of how your proposal would
improve current code to change my view.

Cheers,

On Fri, Sep 29, 2017 at 12:20 PM, Erling Hellenäs <[email protected]>
wrote:

Hi all!

See comments below.

Cheers,
Erling

On 2017-09-28 23:45, Louis de Forcrand wrote:

I don't really understand what you wish to add either, Erling.

If you want to use explicit J syntax, you could write an explicit verb.

The main difference between tacit J and explicit J, as I see it, is not
the syntax as such but that tacit J lacks mutable state.
I think that is the reason some people use it professionally.
Anonymous verbs are easier to create. This will change if Henry's request
is implemented.
I have learned some things about how to simplify problem solutions when I
messed with tacit J, but yes, if my request does not pass, I guess I will
stick to explicit J.

You write:

Particularly to create what you most commonly need, a sequence of
monadic verbs, each acting on the result of the verb to the right.
Well, it is not complicated as such, but for some reason people don't
like
the obvious way to do it, which is [: f [: g [: h ]. Then they dive into
a
mess of complications. I mean the cap should not be necessary. That
simple
right to left execution should be the default, possibly modified with
parenthesis. That tacit and explicit J should have the same basic syntax.

f@:g@:h?
In addition, I disagree with your last two sentences. What's the point of
having tacit syntax if it's the same as explicit syntax? If you want
explicit syntax, write an explicit verb; other times tacit syntax is really
practical.
In an explicit verb, simple right to left execution *is* the default.

I don't know in what way the tacit syntax could ever be better than what I
describe. It is a lot more complex but it is not even shorter. I doubt it
is good even for anything it was created to be used for.

In any case I don't really see how the rest of your suggestion differs
from Henry's (.). verbs, which I like very much by the way.

Yes, well, there is a question if we should move on, work on more than one
thread, have non-mutable state, have functions as primary citizens, have
anonymous definitions of adverbs and conjunctions, integrate into
development environments instead of working at a prompt and very much more,
or if we should just keep on doing small changes to a language made for
working at a teletype.
Tacit J seemed like a step in the right direction because it lacks mutable
state. I once thought it was functional programming but as I see it it
isn't. Now we have to go back to explicit J because we recognized tacit J
is not useful. It means we made very little progress since the teletypes?


Cheers,
Louis

On 28 Sep 2017, at 14:53, Raul Miller <[email protected]> wrote:
Jose's work is impressive, but I try to avoid it because of the extra
complexity it creates when I want to (for example) provide a parameter
in clauses for conjunctions like &. -- the extra complexity can be a
nice mental exercise and maybe even a cure for boredom, but I feel
that I have the right to treat it as unnecessary.

Thanks,

--
Raul


On Thu, Sep 28, 2017 at 8:33 AM, Erling Hellenäs
<[email protected]> wrote:

Hi all !

I am very impressed by Jose's work and I think it is an excellent
illustration to why we need the modification to J I propose.
It is extremely  complicated to do these things which should be simple,
as I
see it. Particularly to create what you most commonly need, a sequence
of
monadic verbs, each acting on the result of the verb to the right.
Well, it is not complicated as such, but for some reason people don't
like
the obvious way to do it, which is [: f [: g [: h ]. Then they dive
into a
mess of complications. I mean the cap should not be necessary. That
simple
right to left execution should be the default, possibly modified with
parenthesis. That tacit and explicit J should have the same basic
syntax. I
tried my ideas of a different tacit J in a test implementation and it
was
great.

Cheers,
Erling Hellenäs


On 2017-09-28 05:29, Jose Mario Quintana wrote:
Hi Erling,

You are right, the adverb (At) produces tacit sentences but it is
really
an
implementation of Dan's pipeline proposal using strand notation via a
Curried adverb (aka, recurrent adverb and multiple adverb).

However, I have written (tacitly) a tacit Curried adverb (xi) which,
using
a lambda-style syntax, produces a tacit verb which in turn, given its
arguments, produces tacit entities.  You might find xi interesting; the
general form is,

t=. [: v0 v1 ... vn '...' xi

The names v0 v1 ... vn should be syntactically verbs (recall, xi is a
Curried adverb) but they can represent nouns, verbs, adverbs, or
conjunctions.  I use undefined names since those are regarded by
default
as
verbs (even if xi does not affect in any way the named verbs).  The
literal
'...' represents a quoted J (or more generally a Jx) sentence.

This is how your example can be written using xi,

     erase 'b v'

     [: v '([: b ''<:b++/\b-~-.b'' xi <''\''=v){."0 v' xi <'\\\//\\\//'
\
   \
    \
    /
   /
   \
    \
     \
     /
    /

There is the nuisance of quotes within quotes and the argument must be
boxed; however, this allows, in general, the verb (t) to produce a
noun, a
verb, an adverb, or a conjunction and to take multiple boxed nouns,
verbs,
adverbs, or conjunctions as its argument.  The following verb (t) acts
directly on a couple of (boxed) verbs and produces a verb,

     t=. [: u v 'u/@:v' xi

     t[:+*:]: NB. Sum of squares
+/@:*:
     t[:+*:]: 1 2 3 4 5
55

     t[:-%:]: NB. Difference of square roots
-/@:%:
     t[:-%:]: 1 2 3 4 5
1.55390522

Note that the Curried higher-order verb (t) is, in effect, acting on
two
arguments: [:-%:]: and 1 2 3 4 5; furthermore, t [:-%:]: performs a
partial
application of the verb (t) acting on [:-%:]: .

The following are variations of the verb produced in [0], the verb (t)
acts on a (boxed) conjunction and produces an adverb,

     t=. [: u '(ver adv u)&:train/adv' xi

     ]`{.`{:`{: (t [:(<adv@:)]:)  NB. Use [:(<'@:')sb in J
]@:({.@:({:@:{:))

     ]`{.`{:`{: (t [:(<adv@ )]:)  NB. Use [:(<'@ ')sb in J
]@({.@({:@{:))

     ]`{.`{:`{: (t [:(<adv&:)]:)  NB. Use [:(<'&:')sb in J
]&:({.&:({:&:{:))

These non-compliant features are not provided by the Jx interpreter;
they
are, in fact, inherited from the J interpreter, the Jx facilities just
make
them a lot more accessible.  Actually, I have written a version
(admittedly
cumbersome) of xi in J; see [1] for a link to a zip archive and the
path
to
a script where xi is defined.

PS.
     erase'u0 u1 u2'
1 1 1
     [: u0 u1 u2 'u0 + u1 + u2' xi 1 ; 2 ; 3
6

     erase'α β γ'
1 1 1
     [: u0 u1 u2 'u0 + u1 + u2' xi [:α β γ]:
α + β + γ

References

[0] [Jprogramming] Gerund composed application
      http://www.jsoftware.com/pipermail/programming/2017-
September/048797.html

[1] J Wicked Toolkit
      http://www.2bestsystems.com/foundation/j/Jx.zip
      \Jx\J\J Wicked Toolkit.ijs

















On Wed, Sep 27, 2017 at 5:10 AM, Erling Hellenäs
<[email protected]>
wrote:

Hi all !
Pascal, I will come back to your post later.

Here is a little compiler written in Jx and compiling, as I understand
it,
tacit code with explicit J syntax into tacit J. I did not test it, I
just
read the post.
http://www.jsoftware.com/pipermail/programming/2017-August/
048143.html
The code snippet Farey is an example of the source code of the little
compiler.
I just think we should not have to use a tacit J compiler from
explicit J
to be able to use explicit J syntax and get a tacit result, a single
verb.
It would obviously be better to use explicit J  syntax in the first
place,
as i see it.

Cheers,

Erling


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