Re: [Groff] Why does tty-char.tmac not represent meaning?

[Ingo Schwarze]

Hi,

Werner LEMBERG wrote on Tue, Jun 20, 2017 at 06:16:27PM +0200:
> Ingo Schwarze wrote:
 
>> What would you think about changing the - admittedly venerable -
>> policy in this respect?  About shifting the top priority onto making
>> the meaning unambiguous in -Tascii output, and only pick a similar
>> graphical shape if that does not endanger properly conveying the
>> meaning?

> I support that.

Thanks for speaking up.

I just added a patch to the bugtracker, hopefully ready for commit:

  https://savannah.gnu.org/bugs/index.php?51302

>  On the other hand, if you use -Tascii instead of
> -Tutf8 today you get what you deserve :-)

You are certainly right that importance of -Tascii has been slowly
decreasing for some time, but it is still occasionally used for
manual page display, i guess, and sometimes even on devices that
don't support UTF-8.  So making -Tascii output intelligible still
seems worthwhile to me, in particular since it is easy to do.

I'm also appending the patch for ease of reference.

Yours,
  Ingo


diff --git a/tmac/tty-char.tmac b/tmac/tty-char.tmac
index 93ca2b7c..5e0ed5af 100644
--- a/tmac/tty-char.tmac
+++ b/tmac/tty-char.tmac
@@ -9,7 +9,8 @@
 .\" - work with all of -Tascii, -Tlatin1, -Tutf8, and -Tcp1047.
 .\" - work on devices that display only the last overstruck character
 .\"   as well as on devices that support overstriking
-.\" - represent the character's graphical shape (not its meaning)
+.\" - help understanding the character's meaning, only aiming to imitate
+.\"   a particular graphical shape when that doesn't hinder understanding
 .\"
 .\" Note that the optical appearance of the definitions contained in this
 .\" file is inferior compared to that of the replacement characters defined
@@ -30,29 +31,29 @@
 .tty-char \[rn] \*[tty-rn]
 .tty-char \[ua] \z|^
 .tty-char \[da] \z|v
-.tty-char \[sc] S
+.tty-char \[sc] <section>
 .tty-char \[ct] \z/c
-.tty-char \[dg] \z|-
-.tty-char \[dd] \z|=
-.tty-char \[ib] (\z=_
-.tty-char \[ip] \z=_)
-.tty-char \[sb] (=
-.tty-char \[sp] =)
-.tty-char \[if] oo
-.tty-char \[pt] oc
+.tty-char \[dg] <*>
+.tty-char \[dd] <**>
+.tty-char \[ib] <subset\~or\~equal>
+.tty-char \[ip] <superset\~or\~equal>
+.tty-char \[sb] <proper\~subset>
+.tty-char \[sp] <proper\~superset>
+.tty-char \[if] <infinity>
+.tty-char \[pt] <proportional\~to>
 .tty-char \[es] {}
-.tty-char \[ca] (^)
-.tty-char \[cu] U
-.tty-char \[de] o
-.tty-char \[di] -:-
-.tty-char \[tdi] -:-
+.tty-char \[ca] <intersection>
+.tty-char \[cu] <union>
+.tty-char \[de] <degree>
+.tty-char \[di] /
+.tty-char \[tdi] /
 .tty-char \[no] ~
 .tty-char \[tno] ~
-.tty-char \[gr] \Z'\*[tty-rn]'V
-.tty-char \[is] \z'\z,I
-.tty-char \[mo] E
-.tty-char \[pd] a
-.tty-char \[sr] \e/
+.tty-char \[gr] <gradient>
+.tty-char \[is] <integral>
+.tty-char \[mo] <element\~of>
+.tty-char \[pd] <del>
+.tty-char \[sr] <sqrt>
 .tty-char \[*C] \z_H
 .tty-char \[*D] \z_/\z_\e
 .tty-char \[*F] \zIO
@@ -103,31 +104,31 @@
 .if c\[md] .tty-char \[pc] \[md]
 .if c\[pc] .tty-char \[md] \[pc]
 .if c\[pc] .tty-char \[a.] \[pc]
-.tty-char \[Im] I
-.tty-char \[Re] R
+.tty-char \[Im] <Im>
+.tty-char \[Re] <Re>
 .tty-char \[/L] \z/L
 .tty-char \[/l] \z/l
-.tty-char \[%0] %o
+.tty-char \[%0] <permille>
 .tty-char \[ao] o
 .tty-char \[a"] """"
 .tty-char \[ab] \z'`
 .tty-char \[ah] v
 .tty-char \[ho] \[ac]
-.tty-char \[/_] \z_/
+.tty-char \[/_] <angle>
 .tty-char \[=~] =~
 .tty-char \[|=] -~
-.tty-char \[Ah] N
-.tty-char \[CR] _|
-.tty-char \[fa] \z-V
-.tty-char \[nm] \z/E
-.tty-char \[pp] \z_|
+.tty-char \[Ah] <Aleph>
+.tty-char \[CR] <cr>
+.tty-char \[fa] <for\~all>
+.tty-char \[nm] <not\~element\~of>
+.tty-char \[pp] <perpendicular>
 .tty-char \[sd] ''
-.tty-char \[st] -)
-.tty-char \[te] 3
+.tty-char \[st] <such\~that>
+.tty-char \[te] <there\~exists>
 .if c\[md] .tty-char \[tf] .\[md].
-.tty-char \[tf] .:.
+.tty-char \[tf] <therefore>
 .if c\[md] .tty-char \[3d] .\[md].
-.tty-char \[3d] .:.
+.tty-char \[3d] <therefore>
 .tty-char \[wp] p
 .tty-char \[~~] ~~
 .tty-char \[Fn] \z,f
@@ -153,13 +154,13 @@
 .tty-char \[Of] \z_a
 .tty-char \[Fo] <<
 .tty-char \[a-] \*[tty-rn]
-.tty-char \[S2] 2
-.tty-char \[S3] 3
-.tty-char \[ps] 9|
+.tty-char \[S2] ^2
+.tty-char \[S3] ^3
+.tty-char \[ps] <paragraph>
 .tty-char \[md] .
 .tty-char \[pc] .
 .tty-char \[ac] ,
-.tty-char \[S1] 1
+.tty-char \[S1] ^1
 .tty-char \[Om] \z_o
 .tty-char \[Fc] >>
 .tty-char \[r?] \z'c
@@ -230,7 +231,7 @@
 .tty-char "\[I .]" I
 .\"tty-char \[:y] \ij
 .tty-char \[arrowvertex] |
-.tty-char \[mc] \z,u
+.tty-char \[mc] <micro>
 .cp \n[_C]
 .
 .ie '\*(.T'cp1047' \