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Re: Optional Arguments
From: |
pietru |
Subject: |
Re: Optional Arguments |
Date: |
Mon, 7 Dec 2020 15:24:36 +0100 |
> Sent: Monday, December 07, 2020 at 2:06 PM
> From: tomas@tuxteam.de
> To: pietru@caramail.com
> Cc: "Alexis Roda" <alexis.roda.villalonga@gmail.com>, "Help Gnu Emacs"
> <help-gnu-emacs@gnu.org>
> Subject: Re: Optional Arguments
>
> 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"
Hmmm. Variables local to function.
> 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 :)
Correct
> 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 :)
Yes, it would mess up.
> Cheers
> - t
>
- Optional Arguments, pietru, 2020/12/06
- Re: Optional Arguments, Alexis Roda, 2020/12/07
- Re: Optional Arguments, pietru, 2020/12/07
- Re: Optional Arguments, tomas, 2020/12/07
- Re: Optional Arguments, Anders Dalskov, 2020/12/07
- Re: Optional Arguments,
pietru <=
- Re: Optional Arguments, tomas, 2020/12/07
- Re: Optional Arguments, pietru, 2020/12/07
- Re: Optional Arguments, Arthur Miller, 2020/12/07
- Re: Optional Arguments, pietru, 2020/12/07
- Re: Optional Arguments, Michael Heerdegen, 2020/12/07
- Re: Optional Arguments, pietru, 2020/12/07
- Re: Optional Arguments, Arthur Miller, 2020/12/07
- Re: Optional Arguments, pietru, 2020/12/07
- Re: Optional Arguments, Alexis Roda, 2020/12/07
- Re: Optional Arguments, pietru, 2020/12/07