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Re: Functions with multiple optional arguments


From: Heime
Subject: Re: Functions with multiple optional arguments
Date: Mon, 17 Oct 2022 05:42:53 +0000

------- Original Message -------
On Monday, October 17th, 2022 at 4:05 AM, Jean Louis <bugs@gnu.support> wrote:


> * Heime via Users list for the GNU Emacs text editor help-gnu-emacs@gnu.org 
> [2022-10-17 00:06]:
> 
> > Have been writing a function that has two optional arguments. It is
> > turning out to be a difficult task in situations when one in missing
> > an argument. Anybody has experience about this, as I have not seen
> > much code with multiple optional arguments.
> 
> 
> If argument is optional but required by your function, I use this method:
> 
> (defun my-fun (&optional title description)
> (let ((title (or title "Best Movie"))
> (description (or description "Description")))
> (message "%s: %s" title description)))
> 
> (my-fun)

I see that the trick is to assign defaults that way.  I like it, very clever.



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