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Re: evaluating numbers
From: |
Stefan Monnier |
Subject: |
Re: evaluating numbers |
Date: |
Sat, 09 Nov 2019 23:47:34 -0500 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) |
>>>> Characters are just integers in Emacs.
>>> I know that. You're not really answering the above question. When people
>>> expect a character to be returned, they expect a character and not
>>> a code point.
>> Emacs can't know what the user expects.
> Developers can know.
>>> How useful is:
>>> (decode-char 'emacs 345)
>>> 345 (#o531, #x159)
>> And the code that displays "345 (#o531, #x159)" doesn't know that this
>> 345 is coming out of a function which is expected to return characters.
> Considering the documentation of decode-char ("returns a character"), that's
> either an implementation error or a documentation error...
So you're suggesting that the eval-expression function should look at
the `car` of the expression that it evaluated, then fetch its docstring
and see if it claims to return a character?
I'd encourage you try and write such a hack. Then consider whether (and
how) it should try and handle cases such as
(let ((x 345)) (decode-char 'emacs x))
or
(1+ (decode-char 'emacs 345))
or
(funcall #'decode-char 'emacs 345)
or
(aref s 3)
[ Side note: I'm the guy who wrote the code that displays those ?<char>
thingies, and I'm a great fan of them (and I remove the
eval-expression-print-maximum-character limit). But I'll also note
that if you want to see the char, you can simply wrap your expression
inside a `string` call, as in M-: (string (decode-char 'emacs 345)) RET ]
I think you're just beginning to discover that XEmacs's decision to have
characters as a built-in type, separate from integers, does occasionally
offer some benefits ;-)
Stefan
- Re: evaluating numbers, (continued)
- Re: evaluating numbers, Juri Linkov, 2019/11/16
- Re: evaluating numbers, Eli Zaretskii, 2019/11/17
- Re: evaluating numbers, Juri Linkov, 2019/11/17
- Re: evaluating numbers, Juri Linkov, 2019/11/14
- Re: evaluating numbers, Stefan Monnier, 2019/11/09
- Re: evaluating numbers, Jean-Christophe Helary, 2019/11/09
- Re: evaluating numbers,
Stefan Monnier <=
- Re: evaluating numbers, Jean-Christophe Helary, 2019/11/13
- Re: evaluating numbers, Stefan Monnier, 2019/11/14
- Re: evaluating numbers, Eli Zaretskii, 2019/11/14
- Re: evaluating numbers, Jean-Christophe Helary, 2019/11/14
- Re: evaluating numbers, Noam Postavsky, 2019/11/14
- Re: evaluating numbers, Eli Zaretskii, 2019/11/14
- Re: evaluating numbers, Jean-Christophe Helary, 2019/11/15
- Re: evaluating numbers, Eli Zaretskii, 2019/11/15