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bug#41347: 28.0.50; calculator.el: Cannot input negative exponents
From: |
Eli Barzilay |
Subject: |
bug#41347: 28.0.50; calculator.el: Cannot input negative exponents |
Date: |
Sun, 17 May 2020 16:26:39 -0400 |
On Sun, May 17, 2020 at 7:08 AM Mattias Engdegård <mattiase@acm.org> wrote:
>
> > @@ -863,7 +863,7 @@ calculator-string-to-number
> > (let* ((str (replace-regexp-in-string
> > "\\.\\([^0-9].*\\)?$" ".0\\1" str))
> > (str (replace-regexp-in-string
> > - "[eE][+-]?\\([^0-9].*\\)?$" "e0\\1" str)))
> > + "[eE]\\([+-]?\\)?$" "e\\10" str)))
> > (float (string-to-number str)))))
>
> Thanks for the report and the suggested patch! However, I'm not sure
> what either of these replace-regexp-in-string calls are good for. The
> first one possibly to accept 1.e23 instead of 1e23; the second one is
> less clear. Frankly, I think we can drop both.
>
> Eli, do you remember?
Sidenote: there's not much point in the double "?" in "\\([+-]?\\)?".
But more to the point, I don't remember why I switched to the regexp
mess in the first place. The original code:
(car (read-from-string
(cond ((equal "." str) "0.0")
((string-match "[eE][+-]?$" str) (concat str "0"))
((string-match "\\.[0-9]\\|[eE]" str) str)
((string-match "\\." str)
;; do this because Emacs reads "23." as an integer
(concat str "0"))
((stringp str) (concat str ".0"))
(t "0.0"))))
makes the intention clear -- the idea is to mimic common calculators
where you can type "3." or "3e" and get 3. (Re the fix from a short
while ago, the comment also shows that the original intention was to
always get a float.)
It looks like going back to a simplified (due to the float) version of
this would be better. Also testing that the thing I mentioned in the
log still works ("e+" using "+" as an operator).
--
((x=>x(x))(x=>x(x))) Eli Barzilay:
http://barzilay.org/ Maze is Life!