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RE: [External] : menu-item uses no dot period before item-property-list


From: uzibalqa
Subject: RE: [External] : menu-item uses no dot period before item-property-list in examples
Date: Mon, 17 Jul 2023 16:56:57 +0000

------- Original Message -------
On Tuesday, July 18th, 2023 at 4:36 AM, Drew Adams <drew.adams@oracle.com> 
wrote:


> > > > So why bother users in the manual why that is never actually used.
> > > > (menu-item item-name real-binding item-property-list)
> > > 
> > > I hope you meant this, which is not the same thing:
> > > (menu-item item-name real-binding
> > > . item-property-list)
> > > 
> > > item-property-list is not an element of the
> > > overall list. It's "spliced" into that list,
> > > as its tail.
> > 
> > Actual code implementations using menu-item does not include
> > '.' before 'item-property-list'.
> > (menu-item item-name real-binding . item-property-list)
> 
> 
> Look again. item-property-list must be a list.
> That list is not included as an element in
> the list that starts (menu-item....
> 
> Instead, the elements of item-property-list
> are included as elements of list (menu-item....
> That's apparently what you're not getting.
> 
> Example:
> 
> '(menu-item "Load" diredp-load-this-file
> :help "Load this Elisp file")
> 
> item-name is "Load".
> real-binding is diredp-load-this-file
> item-property-list is
> this 2-element list: (:help
> "Load this Elisp file")
> 
> You do not see this:
> 
> '(menu-item "Load" diredp-load-this-file
> (:help "Load this Emacs Lisp file"))
> ^ ^
> 
> which is equal to this:
> 
> '(menu-item "Load" diredp-load-this-file
> . ((:help "Load this Emacs Lisp file")))
> ^ ^ ^
> 
> What you do see is equal to this:
> 
> '(menu-item "Load" diredp-load-this-file
> . (:help "Load this Emacs Lisp file"))
> 
> Now ask yourself why the syntax spec
> shows a dot before item-property-list.
> 
> If you still don't get it, take a break,
> stand on your head for a few minutes, run
> around the block, then study this again...
> till you do.
> 
> When you finally get it, go look at the
> Emacs documentation that introduces lists
> and their notation. You'll find it very
> clear, I think. All of this is explained.
> 
> And yes, you should read the basics, such
> as notation, before you start trying to
> interpret the use of such notation in the
> doc. E.g., before you try to interpret the
> presentation of the syntax of extended menu
> items, learn about Lisp dot notation.
> 
> And as has also been said, this isn't just
> a doc notational convention. It's in fact
> the actual, effective, real-life Lisp list
> syntax.

Will check things out.
 
> Crawl, then walk, before trying to run.
> That way, you'll find that running isn't
> so difficult, mysterious, confusing, scary,
> or user-unfriendly.
> 
> And that way maybe you'll stop kvetching
> that you're "drowning" and that folks need
> to quickly line up and start saving you.
> 
> Don't presume that those trying to help you
> don't get it. You're not the first person
> to learn Lisp, and you're not the first one
> that people here, and Emacs itself, has
> helped.
> 
> And maybe read this - it might be humbling.
> 
> https://en.wikipedia.org/wiki/Dunning–Kruger_effect

So now I am low-ability and the rest of you are high-ability.  Have you heard 
about "expert blindness" or "the curse of knowledge" ?  Individuals with high 
ability or expertise overlooking or underestimating certain problems, leading 
to negative outcomes or disasters.



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