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From: <tomas@tuxteam.de>
To: pietru@caramail.com
Cc: Help Gnu Emacs <help-gnu-emacs@gnu.org>
Subject: Re: Optional Arguments
Date: Mon, 7 Dec 2020 14:06:30 +0100	[thread overview]
Message-ID: <20201207130630.GA10719@tuxteam.de> (raw)
In-Reply-To: <trinity-c2aa36dd-59c5-4cbf-a06e-9642899c6c12-1607344654425@3c-app-mailcom-bs11>

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On Mon, Dec 07, 2020 at 01:37:34PM +0100, pietru@caramail.com wrote:
> 
> 
> > Sent: Monday, December 07, 2020 at 9:16 AM
> > From: "Alexis Roda" <alexis.roda.villalonga@gmail.com>
> > To: pietru@caramail.com
> > Cc: "Help Gnu Emacs" <help-gnu-emacs@gnu.org>
> > Subject: Re: Optional Arguments
> >
> > Hi,
> > 
> > Not sure what your question is.
> 
> It is bit confusing.
> 
> I want to use typh-word-markers to compute ma and mb so I can use the
> two values in another function.  Had put (interactive) in my effort to
> test it, but created problems as you say.  The function would be called
> when cursor is on a word, so that I get the word "beg" and "end".
> 
> (defun typh-word-markers (ma mb)

[...]

As Alexis already said, the parameters in your function aren't probably
doing what you think they do. Consider:

  (setq ma 15)
  (setq mb 26)
  
  (defun foo (ma mb)
    (setq ma 5)
    (setq mb 6)
    (message "ma: %d mb: %d" ma mb))
  
  (foo ma mb)

=> "ma: 5 mb: 6"

  (message "ma: %d mb: %d" ma mb)

=> "ma: 15 mb: 26"

I suspect you are passing the parameters to get their values
"outside" the function. I can only guess that, because you don't
show any context (take this into account to help others help
you :)

But this won't work, because the (setq ...) whithin the function
doesn't "see" the variables outside, but creates variables inside,
initialized to whatever /values/ you pass to the function at call
time.

In other words: what would you expect your function `typh-word-markers'
do do if you call it like so:

  (typh-word-markers 15 16)

...would you expect it to change the number 15 to whatever the word's
beginning position is? You would mess up maths with that :)

Cheers
 - t

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  reply	other threads:[~2020-12-07 13:06 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-07  3:17 Optional Arguments pietru
2020-12-07  8:16 ` Alexis Roda
2020-12-07 12:37   ` pietru
2020-12-07 13:06     ` tomas [this message]
2020-12-07 13:35       ` Anders Dalskov
2020-12-07 14:24       ` pietru
2020-12-07 15:38         ` tomas
2020-12-07 18:13           ` pietru
2020-12-07 19:01             ` Arthur Miller
2020-12-07 19:42               ` pietru
2020-12-07 19:54                 ` Michael Heerdegen
2020-12-07 20:21                   ` pietru
2020-12-07 20:52                   ` Arthur Miller
2020-12-07 21:21                     ` pietru
2020-12-07 19:51             ` Alexis Roda
2020-12-07 15:06       ` pietru
2020-12-07 15:51         ` tomas
2020-12-07 17:51           ` pietru
2020-12-07 18:33             ` Arthur Miller
2020-12-07 18:49               ` pietru
2020-12-07 20:13             ` Stefan Monnier
2020-12-07 20:25               ` pietru
2020-12-07 20:39                 ` Christopher Dimech

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