Re: Passing optional arguments for use with internal functions

[uzibalqa]

------- Original Message -------
On Saturday, July 29th, 2023 at 5:11 AM, Emanuel Berg <incal@dataswamp.org> 
wrote:


> Heime wrote:
> 
> > > Optional arguments defaults to nil, if that is an
> > > acceptable value you can use it as you do, if not you can
> > > check if it is nil first thing in the function and if it
> > > is, set it to something that works, e.g.
> > > 
> > > (or arg (setq arg 0))
> > 
> > Does the condition you specified work whether the binding is
> > lexical or dynamic ?
> 
> 
> If there is an optional argument with that name yes, since
> formal parameters (function arguments) are always lexical.

Yes, I am discussing (or arg (setq arg 0)) in the context of
an optional argument by that name, for the purpose of setting
a default if it was not specified. 
 
> ;;; -- lexical-binding: nil --
> 
> (defvar arg)
> (setq arg 2)
> 
> (defun echo-arg (&optional arg)
> (or arg (setq arg 1))
> (message "%s" arg) )
> 
> ;; (echo-arg)
> 
> This will still echo 1.

Now that there has been a change from dynamic to lexical binding,
this becomes a problem.  What command should one use to set a default
value to an optional argument for the current lexical binding files ? 
 
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