[Jprogramming] @ and @: (atop and at)

[Linda A Alvord]

At ;east now I expect f@:g and [:f g to agree.

That is not the case with @ (and it even makes sense, finally)

Linda

-----Original Message-----
From: Programming [mailto:programming-bounces at forums.jsoftware.com] On Behalf Of Raul Miller
Sent: Sunday, January 24, 2016 1:43 PM
To: Programming forum
Subject: Re: [Jprogramming] @ and @: (atop and at)

Note, however, that the "top-to-bottom" aspect is coincidental, and that k and g are not equivalent.

   G=: 13 :'%%:-+*:y'
   5!:4<'G'
  ┌─ [:
  ├─ %
──┤    ┌─ [:
  │    ├─ %:
  └────┤    ┌─ [:
       │    ├─ -
       └────┤    ┌─ [:
            └────┼─ +
                 └─ *:
   k 9
5.19987e16
   g 9
0j_0.111111
   G 9
0j_0.111111

(And, as usual, I expect that list readers will have to ensure that they're using an appropriate (fixed width) font to see the tree displays.  I think the line of responsibility for that issue looks approximately like printing press tradition -> Knuth -> education system -> Microsoft -> education system -> Google.)

FYI,

--
Raul


On Sun, Jan 24, 2016 at 10:02 AM, Brian Schott <schott.brian at gmail.com>
wrote:

> Linda,
>
> Thank you for your f, g, and h examples.
> Together with Henry's long explanations, they helped me better able to
> understand the tree form. I think **now** I can see that the order of
> parsing is from left to right before execution which is from bottom to top.
> I used the fork example tree below to see this as well.
>
>    k =: % %: - + *:
>    5!:4 <'k'
>   ┌─ %
>   ├─ %:
> ──┤    ┌─ -
>   └────┼─ +
>        └─ *:
>
>    g=: 13 :'%@%:@- at +@*:y'
>    5!:4 <'g'
>                         ┌─ %
>                   ┌─ @ ─┴─ %:
>             ┌─ @ ─┴─ -
>       ┌─ @ ─┴─ +
> ── @ ─┴─ *:
>
> Now compare the trees of g and k above. (For purposes of comparison, the
> defined k was constructed with the same order of verbs as the defined g.)
>
> Both the definitions of g and k are unadorned with parentheses and both are
> executed from bottom to top in their respective trees. But whereas g's tree
> is upward sloping, k's is downward sloping and the right to left parsing
> order in the trees describe the opposition of the two.
>
> These relative asymmetries **show** me a little better why you have for a
> long time wanted to concentrate on developing verbs in only one of the two
> ways (using forks and not conjunctions, in your case) to limit complexity.
>
>
> On Sat, Jan 23, 2016 at 11:08 PM, Linda A Alvord <lindaalvord at verizon.net>
> wrote:
>
> > Guess how this tree will look before you look.
> >
> > h=: 13 :'((((%@%:)@-)@+)@*:)y'
> > 5!:4 <'h'
> >
> > Linda
> >
> > -----Original Message-----
> > From: Programming [mailto:programming-bounces at forums.jsoftware.com] On
> > Behalf Of Linda A Alvord
> > Sent: Saturday, January 23, 2016 2:01 AM
> > To: programming at jsoftware.com
> > Subject: Re: [Jprogramming] @ and @: (atop and at)
> >
> > Henry, Your explanation of how the conjunctions are parsed helped make
> the
> > tree diagrams make more sense. I gave up my idea.
> >
> >
> >
> >    f=: 13 :'(%@(%:@(-@(+@*:))))y'
> >
> >    5!:4 <'f'
> >
> >       ┌─ %
> >
> > ── @ ─┤     ┌─ %:
> >
> >       └─ @ ─┤     ┌─ -
> >
> >             └─ @ ─┤     ┌─ +
> >
> >                   └─ @ ─┴─ *:
> >
> >    g=: 13 :'%@%:@- at +@*:y'
> >
> >    5!:4 <'g'
> >
> >                         ┌─ %
> >
> >                   ┌─ @ ─┴─ %:
> >
> >             ┌─ @ ─┴─ -
> >
> >       ┌─ @ ─┴─ +
> >
> > ── @ ─┴─ *:
> >
> >
> > --
> (B=)
> ----------------------------------------------------------------------
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>
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