Re: Utf8 symbols in completing-read completion item

[Heime <heimeborgia@protonmail.com>]

------- Original Message -------
On Thursday, October 20th, 2022 at 9:02 PM, Jean Louis <bugs@gnu.support> wrote:


> * Heime via Users list for the GNU Emacs text editor help-gnu-emacs@gnu.org [2022-10-20 15:26]:
> 
> > Am using "completing-read" to input greek letters. To introduce the corresponding utf8
> > symbol I just copy it in the completion item, then match with a pcase that includes the
> > utf8 symbol. Is this the correct way of doing so?
> 
> 
> Your Lisp formatting is not readable:
> 
> (defun nuket-greek (actm)
> "TODO"
> 
> (interactive
> (list
> (let ( (cseq '("alpha α" "beta β" "gamma" "delta" "epsilon" "zeta" "eta")) )
> (completing-read "Nuke: " cseq nil t "eta"))))
> 
> (pcase actm
> 
> ("alpha α" (insert "\\alpha"))
> 
> ("beta β" (insert "\\beta"))
> 
> ("eta" (insert "\\eta"))) )
> 
> 
> I can read better when I format it this way:
> 
> (defun nuket-greek (actm)
> "TODO."
> (interactive
> (list
> (let ((cseq '("alpha α" "beta β" "gamma" "delta" "epsilon" "zeta" "eta")))
> (completing-read "Nuke: " cseq nil t "eta"))))
> (pcase actm
> ("alpha α" (insert "\\alpha"))
> ("beta β" (insert "\\beta"))
> ("eta" (insert "\\eta"))))
> 
> Myself I do not know what is \\alpha, but maybe you use that for
> LaTeX or something. Personally I don't like complicated
> `interactive' statements, it looks ugly. I would use the features that beautiful function` completing-read' offers:
> 
> (completing-read PROMPT COLLECTION &optional PREDICATE REQUIRE-MATCH
> INITIAL-INPUT HIST DEF INHERIT-INPUT-METHOD)
> 
> Read a string in the minibuffer, with completion.
> PROMPT is a string to prompt with; normally it ends in a colon and a space.
> COLLECTION can be a list of strings, an alist, an obarray or a hash table.
> 
> What I see is that you wish to choose something like "alpha α"
> and then to get different result like "\\alpha".
> 
> Following may give you the result automatically, by using hash:
 
So you use hash table because it is fast to process.

Nevertheless, my question is more focused on the best way to insert
utf8 characters in COLLECTION.  Is it acceptable to include utf8 characters
in COLLECTION?  From where does one copy the utf8 characters compatible with
emacs?