Dan,
I am curious... Can you show us some examples of how the label-less label
works as punctuation (separator)?
PS. I enjoyed your ABRACADABRA sneaky solution [0]
[0] [Jprogramming] ABRACADABRA
http://www.jsoftware.com/pipermail/programming/2016-April/044950.html
On Tue, Apr 12, 2016 at 10:49 AM, Dan Bron <[email protected]> wrote:
> Pepe wrote:
> > [0] [Jprogramming] Tacit adverb definitions?
> > http://www.jsoftware.com/pipermail/programming/2006-July/002627.html
> <http://www.jsoftware.com/pipermail/programming/2006-July/002627.html>
> Ha, I’d forgotten about that. I remember having fun with it at the time.
>
> Not having to parenthesize the LHA to a conjunction under certain
> conditions (the pertinent condition being insight under consideration in
> this thread) came as a lovely little revelation when I was just hacking
> around in the session manager.
>
> I can’t remember what I was playing with at the time, but I do remember
> that little observation being an enjoyable outcome. It might have been when
> I was exploring someone’s assertion (Randy’s, maybe, because of his deep
> experience with APL?) that J evaluates strictly left-to-right.
>
> Anyway, it was in the era when I started to look at J’s grammar directly
> (i.e. trying to actually understand $II.E) after spending years developing
> a subconscious intuition for it.
>
> I’m still not nearly as conversant with J’s grammar, or parsers [in the
> compiler sense] in general as Raul is, nor do I think I expect I ever will
> be. I “get” it (as in, J’s evaluation of sentences I type rarely takes me
> by surprise), but I’d have to put in some effort and thought in order to
> explain it to a third party. And I would probably be forced to explain it
> in more human / intuitive terms than what is spelled out in the parse table.
>
> In the same vein, though I don’t think it was at the same time, I also
> remember a sense of satisfaction when I learned that 3 : ‘label_.’ (a
> label-less label*) could be used as a minimal and semantically-transparent
> J equivalent to APL’s diamond or C-like languages’ semicolons within
> explicit definitions.
>
> That is, label_. acts as a logical line separator that forces the
> expression on the left to be evaluated to completion before the expression
> on its right is executed.
>
> This is distinct from normal labels, because if you wanted to use those,
> you’d have to vary the label names if you wanted more than one line
> separator in a single definition, which works, but feels like a hack.
>
> It’s also different from Ken’s original suggestion to use ]. (or, in
> today’s terms, 2 : ‘v’), because while that works for (the majority of)
> nouns and verbs, it does “the wrong thing” when one side or the other is an
> operator (i.e. an adverb or conjunction). That is, its scope is limited. As
> punctuation, label_. works for any wordclass.
>
> -Dan
>
> * https://en.wikipedia.org/wiki/The_Gateless_Gate <
> https://en.wikipedia.org/wiki/The_Gateless_Gate>
>
>
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