pcase on multiple conditions

pcase on multiple conditions

[Heime]

Is this the way to test for two values to perform the same operation?

 (pcase complt

    ((or 3 4)

       (myfunc)))

Re: pcase on multiple conditions

[Jean Louis]

* Heime <heimeborgia@protonmail.com> [2022-10-28 09:49]:
> Is this the way to test for two values to perform the same operation?
> 
>  (pcase complt
> 
>     ((or 3 4)
> 
>        (myfunc)))

With `or' it will become true if any of values is true. If you need to
test for all values to be true, use `and'.

I don't know how it is called in English, I believe "logics". And I
still remember learning it in primary school. It was not related to
programming, just mathematics. In many countries they teach it in
secondary schools. My remark is not related to your request.

-- 
Jean

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Re: pcase on multiple conditions

[Michael Heerdegen]

Jean Louis <bugs@gnu.support> writes:

> * Heime <heimeborgia@protonmail.com> [2022-10-28 09:49]:
> > Is this the way to test for two values to perform the same operation?
> > 
> >  (pcase complt
> > 
> >     ((or 3 4)
> > 
> >        (myfunc)))
>
> With `or' it will become true if any of values is true.

`pcase' patterns are not values.  Your interpretation of the semantics
of this `or` pattern is wrong.

Michael.

Re: pcase on multiple conditions

[Heime]

------- Original Message -------
On Friday, October 28th, 2022 at 7:44 AM, Michael Heerdegen <michael_heerdegen@web.de> wrote:


> Jean Louis bugs@gnu.support writes:
> 
> > * Heime heimeborgia@protonmail.com [2022-10-28 09:49]:
> > 
> > > Is this the way to test for two values to perform the same operation?
> > > 
> > > (pcase complt
> > > 
> > > ((or 3 4)
> > > 
> > > (myfunc)))
> > 
> > With `or' it will become true if any of values is true.
> 
> 
> `pcase' patterns are not values. Your interpretation of the semantics of this` or` pattern is wrong.
> 
> Michael.

I want to call "myfunc" when "complt" has value 3 or 4.

Re: pcase on multiple conditions

[Michael Heerdegen]

Heime <heimeborgia@protonmail.com> writes:

> I want to call "myfunc" when "complt" has value 3 or 4.

Looks ok.

Maybe consider to use `cl-case' which has simpler semantics (or `cond').
Learning `pcase' takes some time itself.

Michael.

Re: pcase on multiple conditions

[Jean Louis]

* Michael Heerdegen <michael_heerdegen@web.de> [2022-10-28 10:46]:
> Jean Louis <bugs@gnu.support> writes:
> 
> > * Heime <heimeborgia@protonmail.com> [2022-10-28 09:49]:
> > > Is this the way to test for two values to perform the same operation?
> > > 
> > >  (pcase complt
> > > 
> > >     ((or 3 4)
> > > 
> > >        (myfunc)))
> >
> > With `or' it will become true if any of values is true.
> 
> `pcase' patterns are not values.  Your interpretation of the semantics
> of this `or` pattern is wrong.

I actually skipped to think of pcase, but mentioned only `or' in
general.

(let ((my-number (read-number "Number: ")))
  (pcase my-number
    ((or 3 4) (message "Yes, it is 3 or 4"))
    (t (message "Not 3 or 4")))) ⇒ "Not 3 or 4" for entry of 5

So why this does not work?

-- 
Jean

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Re: pcase on multiple conditions

[Michael Heerdegen]

Jean Louis <bugs@gnu.support> writes:

> (let ((my-number (read-number "Number: ")))
>   (pcase my-number
>     ((or 3 4) (message "Yes, it is 3 or 4"))
>     (t (message "Not 3 or 4")))) ⇒ "Not 3 or 4" for entry of 5
>
> So why this does not work?

It doesn't?

Michael.

Re: pcase on multiple conditions

[Stefan Monnier via Users list for the GNU Emacs text editor]

> (let ((my-number (read-number "Number: ")))
>   (pcase my-number
>     ((or 3 4) (message "Yes, it is 3 or 4"))
>     (t (message "Not 3 or 4")))) ⇒ "Not 3 or 4" for entry of 5
>
> So why this does not work?

It works for me (and it helpfully gives me a warning along the way that
"Pattern t is deprecated.  Use `_' instead").


        Stefan

Re: pcase on multiple conditions

[Emanuel Berg]

Jean Louis wrote:

> I don't know how it is called in English, I believe
> "logics". And I still remember learning it in primary
> school. It was not related to programming, just mathematics.
> In many countries they teach it in secondary schools.
> My remark is not related to your request.

I did it at the university, "Logic & Proof Techniques",
2009-10-02. So I guess we're that much behind, ey?

To be honest that course was a bit of a joke and I agree with
you a kid could and should understand that and/or stuff.

Well, I did anyway and I can assure you that didn't make me
pound my chest thinking I was a genious LOL

-- 
underground experts united
https://dataswamp.org/~incal

Re: pcase on multiple conditions

[Emanuel Berg]

Michael Heerdegen wrote:

>>> Is this the way to test for two values to perform the
>>> same operation?
>>> 
>>>  (pcase complt
>>>     ((or 3 4)
>>>        (myfunc)))
>>
>> With `or' it will become true if any of values is true.
>
> `pcase' patterns are not values. Your interpretation of the
> semantics of this `or` pattern is wrong.

The syntax and semantics are not easy to understand but here
is an example of `pcase' use that should be simple enough, at
least what it does and how to use it.

(defun insert-mail (&optional delim)
  (interactive "P")
  (pcase-let ((`(,delim-beg ,delim-end) (if delim '("<" ">") '("" ""))))
    (insert (format "%s%s%s" delim-beg user-mail-address delim-end)) ))

;; (insert-mail)   ;  incal@dataswamp.org
;; (insert-mail t) ; <incal@dataswamp.org>

-- 
underground experts united
https://dataswamp.org/~incal

Re: pcase on multiple conditions

[Emanuel Berg]

Stefan Monnier via Users list for the GNU Emacs text editor wrote:

>> (let ((my-number (read-number "Number: ")))
>>   (pcase my-number
>>     ((or 3 4) (message "Yes, it is 3 or 4"))
>>     (t (message "Not 3 or 4")))) ⇒ "Not 3 or 4" for entry of 5
>>
>> So why this does not work?
>
> It works for me (and it helpfully gives me a warning along
> the way that "Pattern t is deprecated. Use `_' instead").

`pcase'! I thought we were talking `pcase-let'.

-- 
underground experts united
https://dataswamp.org/~incal

Re: pcase on multiple conditions

[Jean Louis]

* Emanuel Berg <incal@dataswamp.org> [2022-10-30 18:50]:
> Stefan Monnier via Users list for the GNU Emacs text editor wrote:
> 
> >> (let ((my-number (read-number "Number: ")))
> >>   (pcase my-number
> >>     ((or 3 4) (message "Yes, it is 3 or 4"))
> >>     (t (message "Not 3 or 4")))) ⇒ "Not 3 or 4" for entry of 5
> >>
> >> So why this does not work?
> >
> > It works for me (and it helpfully gives me a warning along
> > the way that "Pattern t is deprecated. Use `_' instead").
> 
> `pcase'! I thought we were talking `pcase-let'.

Time for Kottbular 🍖

-- 
Jean

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