bug#22919: calc should use square root symbol to denote square root

bug#22919: calc should use square root symbol to denote square root

[Zephyr Pellerin]

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From 52abdb12d360a8b9c53fe09e215e9a1781d1db46 Mon Sep 17 00:00:00 2001
From: zv <zv@nxvr.org>
Date: Sat, 14 Nov 2015 15:37:08 -0800
Subject: sqrt-compose should use the square root symbol

Signed-off-by: zv <zv@nxvr.org>
---
 lisp/calc/calccomp.el | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lisp/calc/calccomp.el b/lisp/calc/calccomp.el
index 81a035d..821d1b8 100644
--- a/lisp/calc/calccomp.el
+++ b/lisp/calc/calccomp.el
@@ -1017,7 +1017,7 @@
 		    (make-string (+ w 2) ?\_))
 	    (list 'horiz
 		  (if (= h 1)
-		      "V"
+		      "√"
 		    (append (list 'vleft (1- a))
 			    (make-list (1- h) " |")
 			    '("\\|")))
-- 
2.5.0

bug#22919: calc should use square root symbol to denote square root

[Alexis]

Whilst i like the aesthetics of using the actual square root 
symbol
rather than 'V', i use character sets and fonts that make this 
character available. Not everyone does, however, and this change 
would result in
those people getting something like the equivalent of the Unicode 
REPLACEMENT CHARACTER, � (0xFFFD), or a blank space. So i would 
like to suggest this patch not be applied without also either 
adding a way to customise which character gets used as the square 
root symbol, or logic to only display a square root glyph when 
it's certain it's available.


Alexis.

bug#22919: calc should use square root symbol to denote square root

[Glenn Morris]

Alexis wrote:

> to suggest this patch not be applied without also either adding a way
> to customise which character gets used as the square root symbol, or
> logic to only display a square root glyph when it's certain it's
> available.

See eg ruler-mode-fill-column-char and how it uses char-displayable-p.

bug#22919: calc should use square root symbol to denote square root

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Date: Mon, 07 Mar 2016 11:46:25 -0500
> Cc: Zephyr Pellerin <zephyr.pellerin@gmail.com>, 22919@debbugs.gnu.org
> 
> Alexis wrote:
> 
> > to suggest this patch not be applied without also either adding a way
> > to customise which character gets used as the square root symbol, or
> > logic to only display a square root glyph when it's certain it's
> > available.
> 
> See eg ruler-mode-fill-column-char and how it uses char-displayable-p.

That might not work well on a TTY, though.

bug#22919: calc should use square root symbol to denote square root

[Glenn Morris]

Eli Zaretskii wrote:

>> See eg ruler-mode-fill-column-char and how it uses char-displayable-p.
>
> That might not work well on a TTY, though.

In the sense that on a tty char-displayable-p may return nil when the
answer is actually t? If so, I don't think that matters.
Or vice versa? Then just throw in an "(and (display-graphic-p) ..."
We're just talking about a default, after all.

BTW, there's probably more symbols that square-root that this applies
to, so maybe a list of (symbol . character) rather than an individual
option for each one?

bug#22919: calc should use square root symbol to denote square root

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Cc: flexibeast@gmail.com,  zephyr.pellerin@gmail.com,  22919@debbugs.gnu.org
> Date: Tue, 08 Mar 2016 02:22:39 -0500
> 
> Eli Zaretskii wrote:
> 
> >> See eg ruler-mode-fill-column-char and how it uses char-displayable-p.
> >
> > That might not work well on a TTY, though.
> 
> In the sense that on a tty char-displayable-p may return nil when the
> answer is actually t? If so, I don't think that matters.
> Or vice versa?

The latter.  On a TTY, that function can only check whether the
terminal encoding supports the character, but it has no way of knowing
whether the terminal emulator will find a glyph in its font for the
particular character.

bug#22919: calc should use square root symbol to denote square root

[Lars Ingebrigtsen]

Glenn Morris <rgm@gnu.org> writes:

> Alexis wrote:
>
>> to suggest this patch not be applied without also either adding a way
>> to customise which character gets used as the square root symbol, or
>> logic to only display a square root glyph when it's certain it's
>> available.
>
> See eg ruler-mode-fill-column-char and how it uses char-displayable-p.

There was then some worry whether that would work on ttys...  but I
think that's perhaps a too-obscure use case to hinder this change, so I
went ahead and applied the patch (with Glenn's suggestions) to Emacs 28.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no