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Re: Passing optional arguments for use with internal functions


From: uzibalqa
Subject: Re: Passing optional arguments for use with internal functions
Date: Wed, 02 Aug 2023 19:24:00 +0000





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------- Original Message -------
On Thursday, August 3rd, 2023 at 6:20 AM, Emanuel Berg <incal@dataswamp.org> 
wrote:


> uzibalqa wrote:
> 
> > To be absolutely sure I understand. If I want to default
> > a function optional argument if it is not used, the command
> > to that that is
> > 
> > (defun dothis x ()
> > (or x (setq x 8)) ; [...]
> > (do-something x)
> > )
> > 
> > And this would always work. In will work if I use the
> > lexical-binding directive at the top of a file. And it would
> > work if I use dynamic-binding directive at the top of
> > a file.
> 
> 
> Correct, as that wouldn't affect them because function formal
> parameters (the argument placeholders) are always under
> lexical/static scope.
> 
> > Calling the command (dothis) will always use x with value 8,
> > and executing (do-something 8) .
> 
> 
> Yes, you forgot about the &optional keyword in your example
> but other than that it is correct.

Right, it should have been  (defun dothis (&optional x)


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



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