Hi guys,
I hope you are all well. Thank you for continuing to look at this.
Can you please explain through each step how this function is
parsed/processed?
Please run it. Give attention to your behavior through each step.
Step1. Function definition. Input the function
and hit crtl-Enter on the first line.
extd =: 4 : 0
n=. ((1!:1) 1)
((".@,&'x' n)) A. i. x
)
Step 2. Function execution with inputs. Input the value and hit ctrl-Enter.
30 extd 180548043269214561950911457875657
Step 3. The function escapes for an input. Keyboard input. Input the
characters and hit Enter.
180548043269214561950911457875657
Step 4. Result returned.
Thank you.
Ak
On Tue., Aug. 15, 2023, 08:02 Henry Rich, <henryhr...@gmail.com> wrote:
> Yes, maybe that's where the wrongthink is.
>
> In J terminology, the sentence is first converted to /words/ (most
> languages call these 'tokens'), with the words /evaluated/ as far as
> they can be in isolation. Anything that would be called a
> /self-defining term/ is given a type at this stage. For example,
>
> * is evaluated to be a primitive verb
> & is evaluated to be a primitive conjunction
> ( is evaluated to (
> 'abc' is evaluated to a noun
> 123x is evaluated to an extended integer
> 5 12345678901234567890 (a single word) is evaluated to a list of 2
> floating-point integers
>
> non-self-defining words are given a special type:
>
> foo is evaluated to a name
>
> After the words have been given types and maybe values, they are
> processed right to left according to the parsing rules. During the
> parsing, a name is looked up and replaced by its stored type/value
> (except when it is followed by an assignment copula =. or =:).
>
> On 8/15/2023 9:51 AM, Raul Miller wr
> Henry Rich
ote:
> > I think the inconsistency here is that you're thinking of a rather
> > elaborate parsing system used by some other language.
> >
> > Brief overview of J's parser: A sentence is parsed first by tokenizing
> > it (left to right), then the resulting array of tokens is passed to a
> > shift/reduce parser (right to left). Conversion of numbers from
> > "sequence of characters" to "1 or more numbers" happens during
> > tokenization. Verbs execute during the shift/reduce stage.
> >
> > See also https://www.jsoftware.com/help/dictionary/dicte.htm
> >
>
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