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Re: Elisp function that performs numeric computations
From: |
Marcin Borkowski |
Subject: |
Re: Elisp function that performs numeric computations |
Date: |
Wed, 19 Jan 2022 12:29:15 +0100 |
User-agent: |
mu4e 1.1.0; emacs 28.0.50 |
On 2022-01-19, at 11:14, tomas@tuxteam.de wrote:
> On Wed, Jan 19, 2022 at 10:03:28AM +0100, fatiparty--- via Users list for the
> GNU Emacs text editor wrote:
>> Jan 19, 2022, 19:20 by help-gnu-emacs@gnu.org:
>>
>> >
>> > I would like to construct an elisp function that performs numeric
>> > computations and outputs the result.
>> >
>> > j = rptdepth
>> > w = maxdepth - j
>> > p = w + 1
>> >
>> > output = j + ( (depth - maxdepth - 1) mod p )
>> >
>> I have done as follows. But one problem is: How do I use the output in
>> another elisp function?
>>
>> (defun test (depth maxdepth rptdepth)
>> "Compute depth to use."
>> (interactive)
>>
>> (let* ( (j rptdepth)
>> (w (- maxdepth j))
>> (p (+ w 1))
>> (r (mod (- depth maxdepth 1) p) )
>> (o (+ j r)) )
>>
>> (message "usedepth: %d" o) ))
>
> Exactly the same way the other functions you are using in there do it
> "minus" (aka "-"), "plus" ("+") "mod" and the others).
>
> I seriously recommend you go through the excellent "Emacs Lisp Intro"
> delivered with your documentation.
>
> When you define a function, its "value" (i.e. the result of evaluating
> an expression where this function is the operator) is the last
> expression evaluated in that function. So, to put a very simple example
> (the following function always evaluates to 42);
>
> (defun forty-two ()
> 42)
>
> That's it.
>
> In your case, see "transformation 1".
>
> (defun test (depth maxdepth rptdepth)
> "Compute depth to use."
> (interactive)
>
> (let* ( (j rptdepth)
> (w (- maxdepth j))
> (p (+ w 1))
> (r (mod (- depth maxdepth 1) p) )
> (o (+ j r)) )
> o))
>
> (Note that I just say "o" instead of "message ...": the former says it
> "to the program", the latter "to the user".
>
> You then can invoke your function in your program, like so:
>
> (message "the test is: %d" (test 20 22 19))
>
> ... the expression (test 20 22 19) evaluating to whatever you programmed
> your function to do.
Also, once you are comfortable with the basic building blocks of Elisp,
you'll be able to write a function which returns a value when called
from Elisp and prints it (with `message') when called interactively.
(See
https://www.gnu.org/software/emacs/manual/html_node/elisp/Distinguish-Interactive.html)
Best,
--
Marcin Borkowski
http://mbork.pl
- Elisp function that performs numeric computations, fatiparty, 2022/01/19
- Message not available
- Elisp function that performs numeric computations, fatiparty, 2022/01/19
- Re: Elisp function that performs numeric computations, tomas, 2022/01/19
- Re: Elisp function that performs numeric computations,
Marcin Borkowski <=
- Elisp function that performs numeric computations, fatiparty, 2022/01/19
- Re: Elisp function that performs numeric computations, Sergey Organov, 2022/01/20
- Elisp function that performs numeric computations, fatiparty, 2022/01/21
- Re: Elisp function that performs numeric computations, Emanuel Berg, 2022/01/21
- Re: Elisp function that performs numeric computations, Sergey Organov, 2022/01/21
- Re: Elisp function that performs numeric computations, Emanuel Berg, 2022/01/21
- Re: Elisp function that performs numeric computations, Sergey Organov, 2022/01/21
- Elisp function that performs numeric computations, fatiparty, 2022/01/21
- Re: Elisp function that performs numeric computations, Emanuel Berg, 2022/01/21
- Elisp function that performs numeric computations, fatiparty, 2022/01/21