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[groff] 03/28: groff_char(7): Revise table annotations.
G. Branden Robinson
[groff] 03/28: groff_char(7): Revise table annotations.
Tue, 1 Sep 2020 07:43:03 -0400 (EDT)
gbranden pushed a commit to branch master
in repository groff.
Author: G. Branden Robinson <firstname.lastname@example.org>
AuthorDate: Fri Aug 28 22:36:50 2020 +1000
groff_char(7): Revise table annotations.
...for the later, easier tables.
* Recast characterization of DVI output device as one which doesn't
unify mathematical operators with bracket-building glyphs.
* Clarify how rules and bars "form corners".
* Use more general term "radical" in favor of "square root", but keep
the latter in the text as an concession to non-mathematical readers.
* Say "Bell Systems logo", not "Bell Labs" logo. As noted in the URL in
comments on this page, Dennis Ritchie's memorial webpage makes it
clear that the logo applied to the overall corporation, not the Labs
(and that's probably why it was spelled "\(bs", bot "\(bl").
* Drop all the stuff in "Greek symbols" about the Unicode 3.0 Greek
curly phi switcheroo; putting both \[*f] and \[+f] alongside the 33
font samples in grops(1) works as expected in every case. This may be
because the symbol font (or slanted symbol font) is being fallen back
to in each case, but in any event the escapes work as their
descriptions suggest, rendering the 20 lines of cautionary text from
* Set groff requests with a leading dot.
* Set *roff escapes in bold.
* Say "AT&T troff", not "classical troff".
* Break lines after commas, colons, and semicolons, and before
* Use double quotes for outermost quotation scope.
man/groff_char.7.man | 125 +++++++++++++++++++++++++++++----------------------
1 file changed, 71 insertions(+), 54 deletions(-)
diff --git a/man/groff_char.7.man b/man/groff_char.7.man
index f8fb778..7db8325 100644
@@ -816,9 +816,9 @@ _
request is used to map most of the accents to non-spacing glyph names;
-the values given in parentheses are the original (spacing) ones.
+the values given in parentheses are their spacing counterparts.
@@ -896,15 +896,22 @@ _
The extensible bracket pieces are font-invariant glyphs.
-In classical troff only one glyph was available to vertically extend
-brackets, braces, and parentheses: \[oq]bv\[cq].
+.IR troff ,
+only one glyph was available to vertically extend
+.RB \[lq] \[rs](bv \[rq].
We map it rather arbitrarily to u23AA.
Note that not all devices contain extensible bracket pieces which can
-be piled up with \[oq]\eb\[cq] due to the restrictions of the
-escape's piling algorithm.
+be piled up with
+.RB \[lq] \[rs]b \[rq]
+due to the restrictions of the escape's piling algorithm.
A general solution to build brackets out of pieces is the following
@@ -944,21 +951,33 @@ macro:
Another complication is the fact that some glyphs which represent
-bracket pieces in original troff can be used for other mathematical
-symbols also, for example \[oq]lf\[cq] and \[oq]rf\[cq] which provide
-the \[oq]floor\[cq] operator.
-Other devices (most notably for DVI output) don't unify such
-For this reason, the four glyphs \[oq]lf\[cq], \[oq]rf\[cq],
-\[oq]lc\[cq], and \[oq]rc\[cq] are not unified with similarly looking
+bracket pieces in AT&T
+can be used for other mathematical symbols as well,
+which provide the \[oq]floor\[cq] operator.
+Some output devices,
+.IR grodvi (@MAN1EXT@) ,
+don't unify such glyphs.
+For this reason,
+the four glyphs
+\[oq]rc\[cq] are not unified with similar-looking bracket pieces.
-.BR groff ,
+.IR groff ,
only glyphs with long names are guaranteed to pile up correctly for all
-devices (provided those glyphs exist).
+devices\[em]provided those glyphs exist.
@@ -1106,21 +1125,33 @@ T}
-.SS Rules and lines
+.SS "Rules and lines"
-The font-invariant glyphs \[oq]br\[cq], \[oq]ul\[cq], and \[oq]rn\[cq]
-form corners; they can be used to build boxes.
+The font-invariant glyphs
+form corners when adjacent;
+they can be used to build boxes.
+Note that both the PostScript and the Unicode-derived names of these
+three glyphs are rough approximations.
-Note that both the PostScript and the Unicode-derived names of
-these three glyphs are just rough approximations.
-\[oq]rn\[cq] also serves in classical troff as the horizontal
-extension of the square root sign.
+\[lq]rn\[rq] also serves in AT&T
+as the horizontal extension of the radical
-\[oq]ru\[cq] is a font-invariant glyph, namely a rule of length 0.5m.
+The baseline rule \[lq]ru\[rq] is a font-invariant glyph,
+namely a rule of length 0.5m.
@@ -1137,9 +1168,14 @@ _
\[rs] \e[rs] backslash u005C reverse solidus
-Use \[oq]\e[radicalex]\[cq], not
-\[oq]\e[overline]\[cq], for continuation of square root.
+(see subsection \[lq]Mathematical symbols\[rq] below),
+for continuation of radical signs
@@ -1181,7 +1217,8 @@ _
-The Bell Labs logo is not supported in groff.
+The Bell Systems logo is not supported in
+.IR groff .
@@ -1351,33 +1388,13 @@ T}
.SS "Greek glyphs"
-These glyphs are intended for technical use, not for real Greek;
-normally, the uppercase letters have upright shape, and the lowercase
-ones are slanted.
+These glyphs are intended for technical use,
+not for real Greek;
+the uppercase letters have upright shape,
+and the lowercase ones are slanted.
-There is a problem with the mapping of letter phi to Unicode.
-Prior to Unicode version\ 3.0, the difference between U+03C6, GREEK
-SMALL LETTER PHI, and U+03D5, GREEK PHI SYMBOL, was not clearly
-described; only the glyph shapes in the Unicode book could be used as a
-Starting with Unicode\ 3.0, the reference glyphs have been exchanged and
-described verbally also: In mathematical context, U+03D5 is the stroked
-variant and U+03C6 the curly glyph.
-Unfortunately, most font vendors didn't update their fonts to
-this (incompatible) change in Unicode.
-At the time of this writing (January 2006), it is not clear yet
-whether the Adobe Glyph Names \[oq]phi\[cq] and \[oq]phi1\[cq] also
-change its meaning if used for mathematics, thus compatibility
-problems are likely to happen \[en] being conservative, groff
-currently assumes that \[oq]phi\[cq] in a PostScript symbol font is
-the stroked version.
-In groff, symbol \[oq]\e[*f]\[cq] always denotes the stroked
-version of phi, and \[oq]\e[+f]\[cq] the curly variant.
l l l l lx.
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