Re: Should prefix variable be used in function argument list

[carlmarcos--- via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>]

Jul 8, 2022, 17:41 by incal@dataswamp.org:

> carlmarcos--- via Users list for the GNU Emacs text editor wrote:
>
>> When one wants to use the prefix argument when calling an
>> interactive function, should one include a prefix variable in
>> the function argument list?
>>
>
> Yes, almost always. Keep the function body the same for
> interactive/non-interactive by it referring to the function
> args and not caring which of those ways they got there.
>
>> Furthermore, should the prefix argument be defined as
>> optional?
>>
>
> Yes, when possible, especially when it defaults to something
> that makes sense.
>
> All arguments that have a nil they can take on and that makes
> sense, all those cand be optional if they appear to the right
> of the last argument from that isn't optional. What will
> happen it will just be nil which.
>
>> How would one call the function non-interactively for such
>> function?
>>
>
> By typing it's name between parenthesis and evaluating it.
>
Yes, but what should I put for the prefix value when using the function non-interactively?


>> Is it always necessary to have the prefix argument as the
>> first argument in the function argument list?
>>
>
> No.
>
I thought that because the prefix argument in used first (using C-u N myfunc) then it also has
to be the first argument in the function declaration. 



> -- 
> underground experts united
> https://dataswamp.org/~incal
>