Re: Functions with multiple optional arguments

[Emanuel Berg <incal@dataswamp.org>]

Jean Louis wrote:

>> 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)

Yes, and to set 'description' (and not 'title') you'd do

  (my-fun nil "Poor movie IMO")

CL has another way, more practical probably, to assign default
values to optional arguments and that can be used in Elisp as
well with `cl-defun' ...

-- 
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