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Re: Setting variables, argumunts in defun


From: Philip Kaludercic
Subject: Re: Setting variables, argumunts in defun
Date: Sat, 13 Feb 2021 18:08:06 +0100
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux)

wael-zwaiter@gmx.com writes:

> Is the following valid?
>
> (setq-local devi 0.18
>             scal 1.0)

No, because setq-local only accepts one two arguments (variable and
value). Try C-h o setq-local, and you'll see it's documentation.

>> Sent: Sunday, February 14, 2021 at 4:42 AM
>> From: "Philip Kaludercic" <philipk@posteo.net>
>> To: "Christopher Dimech" <dimech@gmx.com>
>> Cc: wael-zwaiter@gmx.com, "Help Gnu Emacs" <help-gnu-emacs@gnu.org>
>> Subject: Re: Setting variables, argumunts in defun
>>
>> Christopher Dimech <dimech@gmx.com> writes:
>>
>> > I am trying to use pcase on a string, but do need some direction
>> > on how to use it.
>>
>> Pcase is usually used like this
>>
>>         (pcase objv
>>           ("enable"
>>            (setq devi 0.18)
>>            (setq scal 0.2))
>>           ("disable"
>>            (setq devi 0.18)
>>            (setq scal 1.0)))
>>
>> the first element it the expression that the execution depends on, and
>> every possible branch starts with a case. What you are doing looks more
>> like a cond-expression:
>>
>>         (cond ((string-equal objv "enable")
>>                (setq devi 0.18)
>>                (setq scal 0.2))
>>               ((string-equal objv "disable")
>>                (setq devi 0.18)
>>                (setq scal 1.0)))
>>
>> That being said, it's probably better to use a symbol ('enable and
>> 'disable) or a boolean value write this. Exploiting the fact that setq
>> can assign multiple variables at one, you could also write
>>
>>         (if (eq objv 'enable)
>>             (setq devi 0.18
>>                   scal 0.2)
>>           (setq devi 0.18
>>                 scal 1.0))
>>
>> though depending on what you are doing, it might be better to avoid
>> setting global variables in the first place.
>>
>> > (pcase (string-match "enable" objv)
>> >       (
>> >        (setq devi 0.18)
>> >        (setq scal 0.2) )
>> >
>> >     ( (string-match "disable" objv)
>> >      (setq devi 0.0)
>> >      (setq scal 1.0) )
>> >
>> >     )
>> >
>> >
>> >> Sent: Sunday, February 14, 2021 at 4:14 AM
>> >> From: wael-zwaiter@gmx.com
>> >> To: "Help Gnu Emacs" <help-gnu-emacs@gnu.org>
>> >> Subject: Setting variables, argumunts in defun
>> >>
>> >> I would like to set up devi and scal by selecting either one or
>> >> the other.  Wow can I do this in elisp.  Should I pass parameters
>> >> to the function.  Can one pass a string, then check its contents?
>> >>
>> >> (defun deviscal ()
>> >>
>> >>   (setq devi 0.18)
>> >>   (setq scal 0.2)
>> >>
>> >>   (setq devi 0.0)
>> >>   (setq scal 1.0) )
>> >>
>> >>
>> >>
>> >>
>> >>
>> >
>> >
>>
>> --
>>      Philip K.
>>

-- 
        Philip K.

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