Re: How to read an integer from the minibuffer

[Jean Louis <bugs@gnu.support>]

* tomas@tuxteam.de <tomas@tuxteam.de> [2021-11-13 11:18]:
> On Sat, Nov 13, 2021 at 09:36:39AM +0300, Jean Louis wrote:
> > * tomas@tuxteam.de <tomas@tuxteam.de> [2021-11-12 23:25]:
> 
> [...]
> 
> > > Why not simply numberp?
> > > 
> > >   (and (numberp s) (string-to-number s))
> > 
> > (numberp "123") ⇒ nil
> > 
> > It checks if object is number. That is why it is not usable to check
> > if string is actual number.
> 
> D'oh, you are right. That'd been too easy ;-)
> 
> It seems you'll have to go with a regexp, then do string-to-number.
> Then, again, you'll have to decide: what subset of Emacs's number
> input syntax do you want to implement? Signed/unsigned? Integers?
> Floats? Exponential notation? Bases other than 10?

That helped me realize I have to call function different:

(defun string-is-positive-integer-p (s)
  "Return number only if string is positive integer, otherwise
NIL."
  (let* ((s (string-trim s)))
    (cond ((seq-empty-p s) nil)
	  ((string-match "[^0123456789\\.]" s) nil)
	  ((numberp (string-to-number s)) (string-to-number s)))))

-- 
Jean

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