bug#21103: 24.5; LaTeX input mode: add more blackboard bold characters

bug#21103: 24.5; LaTeX input mode: add more blackboard bold characters

[Ansgar Burchardt]

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1. Enable LaTeX input mode: C-\ "TeX" RETURN
2. Typing \Bbb{R} should now result in ℝ,
   but (for example) \Bbb{C} does not result in ℂ.

I miss at least ℂ (field of complex numbers), 𝔽 (generic field), 𝕂
(generic field, German), ℍ (quaternions), 𝕀 (identity map), ℚ (field of
rational numbers), ℤ (ring of integers). Others might miss a few more
that are in common use, see [1].

The attached patch adds all blackboard bold capital characters and "1"
and "2" using the codepoints from the referenced Wikipedia article.

Ansgar

  [1] <https://en.wikipedia.org/wiki/Blackboard_bold>

In GNU Emacs 24.5.1 (x86_64-pc-linux-gnu, GTK+ Version 3.16.4)
 of 2015-06-28 on trouble, modified by Debian
Windowing system distributor `The X.Org Foundation', version 11.0.11701000
System Description:	Debian GNU/Linux testing (stretch)


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From dbe72dfd8d230bb2d7cb17e5d573dd00b9e2d49d Mon Sep 17 00:00:00 2001
From: Ansgar Burchardt <ansgar@43-1.org>
Date: Tue, 21 Jul 2015 13:05:39 +0200
Subject: [PATCH] Add more blackboard bold characters

This patch adds all capital blackboard bold letters and those for "1"
and "2". Most characters are in common use in mathematics, but it does
not seem useful to exclude the few not widely used.

Reference: https://en.wikipedia.org/wiki/Blackboard_bold
---
 lisp/leim/quail/latin-ltx.el | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/lisp/leim/quail/latin-ltx.el b/lisp/leim/quail/latin-ltx.el
index 82c0aa3..366f21c 100644
--- a/lisp/leim/quail/latin-ltx.el
+++ b/lisp/leim/quail/latin-ltx.el
@@ -645,10 +645,34 @@ system, including many technical ones.  Examples:
  ("\\wp" ?℘)
  ("\\wr" ?≀)
 
- ("\\Bbb{N}" ?ℕ)			; AMS commands for blackboard bold
- ("\\Bbb{P}" ?ℙ)			; Also sometimes \mathbb.
+ ("\\Bbb{A}" ?𝔸)			; AMS commands for blackboard bold
+ ("\\Bbb{B}" ?𝔹)			; Also sometimes \mathbb.
+ ("\\Bbb{C}" ?ℂ)
+ ("\\Bbb{D}" ?𝔻)
+ ("\\Bbb{E}" ?𝔼)
+ ("\\Bbb{F}" ?𝔽)
+ ("\\Bbb{G}" ?𝔾)
+ ("\\Bbb{H}" ?ℍ)
+ ("\\Bbb{I}" ?𝕀)
+ ("\\Bbb{J}" ?𝕁)
+ ("\\Bbb{K}" ?𝕂)
+ ("\\Bbb{L}" ?𝕃)
+ ("\\Bbb{M}" ?𝕄)
+ ("\\Bbb{N}" ?ℕ)
+ ("\\Bbb{O}" ?𝕆)
+ ("\\Bbb{P}" ?ℙ)
+ ("\\Bbb{Q}" ?ℚ)
  ("\\Bbb{R}" ?ℝ)
+ ("\\Bbb{S}" ?𝕊)
+ ("\\Bbb{T}" ?𝕋)
+ ("\\Bbb{U}" ?𝕌)
+ ("\\Bbb{V}" ?𝕍)
+ ("\\Bbb{W}" ?𝕎)
+ ("\\Bbb{X}" ?𝕏)
+ ("\\Bbb{Y}" ?𝕐)
  ("\\Bbb{Z}" ?ℤ)
+ ("\\Bbb{1}" ?𝟙)
+ ("\\Bbb{2}" ?𝟚)
  ("--" ?–)
  ("---" ?—)
  ;; We used to use ~ for NBSP but that's inconvenient and may even look like
-- 
2.1.4

bug#21103: 24.5; LaTeX input mode: add more blackboard bold characters

[Lars Ingebrigtsen]

Ansgar Burchardt <ansgar@43-1.org> writes:

> I miss at least ℂ (field of complex numbers), 𝔽 (generic field), 𝕂
> (generic field, German), ℍ (quaternions), 𝕀 (identity map), ℚ (field of
> rational numbers), ℤ (ring of integers). Others might miss a few more
> that are in common use, see [1].
>
> The attached patch adds all blackboard bold capital characters and "1"
> and "2" using the codepoints from the referenced Wikipedia article.

[...]

> This patch adds all capital blackboard bold letters and those for "1"
> and "2". Most characters are in common use in mathematics, but it does
> not seem useful to exclude the few not widely used.

It does seem more consistent to add them all, yes...

> - ("\\Bbb{N}" ?ℕ)			; AMS commands for blackboard bold
> - ("\\Bbb{P}" ?ℙ)			; Also sometimes \mathbb.
> + ("\\Bbb{A}" ?𝔸)			; AMS commands for blackboard bold
> + ("\\Bbb{B}" ?𝔹)			; Also sometimes \mathbb.
> + ("\\Bbb{C}" ?ℂ)
> + ("\\Bbb{D}" ?𝔻)
> + ("\\Bbb{E}" ?𝔼)
> + ("\\Bbb{F}" ?𝔽)
> + ("\\Bbb{G}" ?𝔾)
> + ("\\Bbb{H}" ?ℍ)

(etc)

A question to the other Emacs maintainers -- would a change like this,
which is more than 15 lines, require a copyright assignment?  It's not
very "code-ey"...

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

bug#21103: 24.5; LaTeX input mode: add more blackboard bold characters

[Stefan Kangas]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Ansgar Burchardt <ansgar@43-1.org> writes:
>
>> I miss at least ℂ (field of complex numbers), 𝔽 (generic field), 𝕂
>> (generic field, German), ℍ (quaternions), 𝕀 (identity map), ℚ (field of
>> rational numbers), ℤ (ring of integers). Others might miss a few more
>> that are in common use, see [1].
>>
>> The attached patch adds all blackboard bold capital characters and "1"
>> and "2" using the codepoints from the referenced Wikipedia article.
>
> [...]
>
>> This patch adds all capital blackboard bold letters and those for "1"
>> and "2". Most characters are in common use in mathematics, but it does
>> not seem useful to exclude the few not widely used.
>
> It does seem more consistent to add them all, yes...
>
>> - ("\\Bbb{N}" ?ℕ)			; AMS commands for blackboard bold
>> - ("\\Bbb{P}" ?ℙ)			; Also sometimes \mathbb.
>> + ("\\Bbb{A}" ?𝔸)			; AMS commands for blackboard bold
>> + ("\\Bbb{B}" ?𝔹)			; Also sometimes \mathbb.
>> + ("\\Bbb{C}" ?ℂ)
>> + ("\\Bbb{D}" ?𝔻)
>> + ("\\Bbb{E}" ?𝔼)
>> + ("\\Bbb{F}" ?𝔽)
>> + ("\\Bbb{G}" ?𝔾)
>> + ("\\Bbb{H}" ?ℍ)
>
> (etc)
>
> A question to the other Emacs maintainers -- would a change like this,
> which is more than 15 lines, require a copyright assignment?  It's not
> very "code-ey"...

I searched online, and found the following:
https://www.copyright.gov/circs/circ33.pdf

    Familiar symbols and designs, or a simple combination of a few familiar symbols or designs, are 
    uncopyrightable and cannot be registered with the Office. However, a work of authorship that 
    incorporates one or more familiar symbols or designs into a larger design may be registered if the 
    work as a whole contains a sufficient amount of creative expression.
    
    Examples of familiar symbols and designs include but are not limited to
    • Letters, punctuation, or symbols on a keyboard
    • Abbreviations
    • Musical notation
    • Numbers and mathematical and currency symbols
    • Arrows and other directional or navigational symbols
    • Common symbols and shapes, such as a spade, club, heart, diamond, star, yin yang, or  
       fleur de lys
    • Common patterns, such as standard chevron, polka dot, checkerboard, or houndstooth
    • Well-known and commonly used symbols that contain a minimal amount of expression or  
      are in the public domain, such as the peace symbol, gender symbols, or simple emoticons
    • Industry designs, such as the caduceus, barber pole, food labeling symbols, or hazard 
      warning symbols
    • Familiar religious symbols
    • Common architecture moldings

Given the above, I think this is fine to install with the
Copyright-paperwork-exempt tag.

We could perhaps contact assign@gnu.org if we feel unsure about this,
to hear what they have to say.  Does anyone think we should do that
first, or have any other comments?  Otherwise, I think we should just
install it.

Best regards,
Stefan Kangas

bug#21103: 24.5; LaTeX input mode: add more blackboard bold characters

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Mon, 20 Jan 2020 21:41:30 +0100
> Cc: 21103@debbugs.gnu.org, Ansgar Burchardt <ansgar@43-1.org>
> 
> >> - ("\\Bbb{N}" ?ℕ)			; AMS commands for blackboard bold
> >> - ("\\Bbb{P}" ?ℙ)			; Also sometimes \mathbb.
> >> + ("\\Bbb{A}" ?𝔸)			; AMS commands for blackboard bold
> >> + ("\\Bbb{B}" ?𝔹)			; Also sometimes \mathbb.
> >> + ("\\Bbb{C}" ?ℂ)
> >> + ("\\Bbb{D}" ?𝔻)
> >> + ("\\Bbb{E}" ?𝔼)
> >> + ("\\Bbb{F}" ?𝔽)
> >> + ("\\Bbb{G}" ?𝔾)
> >> + ("\\Bbb{H}" ?ℍ)
> >
> > (etc)
> >
> > A question to the other Emacs maintainers -- would a change like this,
> > which is more than 15 lines, require a copyright assignment?  It's not
> > very "code-ey"...
> 
> I searched online, and found the following:
> https://www.copyright.gov/circs/circ33.pdf
> 
>     Familiar symbols and designs, or a simple combination of a few familiar symbols or designs, are 
>     uncopyrightable and cannot be registered with the Office. However, a work of authorship that 
>     incorporates one or more familiar symbols or designs into a larger design may be registered if the 
>     work as a whole contains a sufficient amount of creative expression.
>     
>     Examples of familiar symbols and designs include but are not limited to
>     • Letters, punctuation, or symbols on a keyboard
>     • Abbreviations
>     • Musical notation
>     • Numbers and mathematical and currency symbols
>     • Arrows and other directional or navigational symbols
>     • Common symbols and shapes, such as a spade, club, heart, diamond, star, yin yang, or  
>        fleur de lys
>     • Common patterns, such as standard chevron, polka dot, checkerboard, or houndstooth
>     • Well-known and commonly used symbols that contain a minimal amount of expression or  
>       are in the public domain, such as the peace symbol, gender symbols, or simple emoticons
>     • Industry designs, such as the caduceus, barber pole, food labeling symbols, or hazard 
>       warning symbols
>     • Familiar religious symbols
>     • Common architecture moldings
> 
> Given the above, I think this is fine to install with the
> Copyright-paperwork-exempt tag.
> 
> We could perhaps contact assign@gnu.org if we feel unsure about this,
> to hear what they have to say.  Does anyone think we should do that
> first, or have any other comments?  Otherwise, I think we should just
> install it.

Richard, are there any reasons to be more lenient with this kind of
changes, wrt to the maximum number of lines we are allowed to accept
without a copyright assignment?  The original patch is here:

  https://debbugs.gnu.org/cgi/bugreport.cgi?bug=21103#5

You can download the patch itself with this URL:

  https://debbugs.gnu.org/cgi/bugreport.cgi?msg=5;filename=0001-Add-more-blackboard-bold-characters.patch;att=1;bug=21103

bug#21103: 24.5; LaTeX input mode: add more blackboard bold characters

[Eli Zaretskii]

> Date: Tue, 21 Jan 2020 20:18:59 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: 21103@debbugs.gnu.org, larsi@gnus.org, ansgar@43-1.org
> 
> > Given the above, I think this is fine to install with the
> > Copyright-paperwork-exempt tag.
> > 
> > We could perhaps contact assign@gnu.org if we feel unsure about this,
> > to hear what they have to say.  Does anyone think we should do that
> > first, or have any other comments?  Otherwise, I think we should just
> > install it.
> 
> Richard, are there any reasons to be more lenient with this kind of
> changes, wrt to the maximum number of lines we are allowed to accept
> without a copyright assignment?  The original patch is here:
> 
>   https://debbugs.gnu.org/cgi/bugreport.cgi?bug=21103#5
> 
> You can download the patch itself with this URL:
> 
>   https://debbugs.gnu.org/cgi/bugreport.cgi?msg=5;filename=0001-Add-more-blackboard-bold-characters.patch;att=1;bug=21103

Discussion with Richard indicated that such changes don't need any
copyright assignments, since they introduce code that is not
copyrightable.  So I've pushed this to the emacs-27 branch, and I'm
closing the bug.

Thanks.