[groff] 07/09: eqn(1): Expand.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit 89f12ae286236ccec1739ab67c8ebd236fdbffb1
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Sun May 21 23:57:13 2023 -0500

    eqn(1): Expand.
    
    * Present how the preprocessor rewrites certain input sequences.
    * Drop examples of `type` and `chartype` usage.
    * Comprehensively present the spacing type assignments used by default,
      per request from Doug McIlroy.
---
 src/preproc/eqn/eqn.1.man | 74 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 51 insertions(+), 23 deletions(-)

diff --git a/src/preproc/eqn/eqn.1.man b/src/preproc/eqn/eqn.1.man
index 6447f2437..42a108891 100644
--- a/src/preproc/eqn/eqn.1.man
+++ b/src/preproc/eqn/eqn.1.man
@@ -377,6 +377,27 @@ constants,
 numeric literals,
 and operators.
 .
+.I eqn \" general
+remaps some input character sequences for convenience in equation entry
+and to ensure that glyphs from an unstyled font are used;
+see
+.MR groff_char @MAN7EXT@.
+.
+.
+.P
+.RS
+.TS
+tab(@);
+Lf(CR) Lf(CR).
++@\[rs][pl]
+-@\[rs][mi]
+\&=@\[rs][eq]
+\&\[aq]@\[rs][fm]
+<=@\[rs][<=]
+>=@\[rs][>=]
+.TE
+.RE
+.
 .
 .\" ====================================================================
 .SS "Automatic spacing"
@@ -431,21 +452,7 @@ Apply
 to
 .RI expression\~ e .
 .
-For example,
-.RB \[lq] times \[rq]
-is defined as if by the following.
-.
-.
-.RS
-.IP
-.EX
-define times \[aq] type "binary" \[rs](mu \[aq]
-.EE
-.RE
-.
 .
-.br
-.ne 7v
 .TP
 .BI chartype\~ "t text"
 Each (unquoted) character
@@ -466,21 +473,42 @@ also assigns a typeface to each character in
 .
 See subsection \[lq]Fonts\[rq] below.
 .
-As an example,
-the default spacing for some punctuation characters is set up as if
-by the following
-.I eqn \" generic
-command.
 .
+.P
+.I @g@eqn \" GNU
+sets up default spacings as if by the following commands.
 .
+.P
 .RS
-.IP
-.EX
-chartype "punctuation" .,;:
-.EE
+.TS
+tab(@);
+Lf(CR) Lf(CR).
+chartype letter@abcdefghiklmnopqrstuvwxyz
+chartype letter@ABCDEFGHIKLMNOPQRSTUVWXYZ
+chartype binary@*\[rs][pl]\[rs][mi]
+chartype relation@<>\[rs][eq]\[rs][<=]\[rs][>=]
+chartype opening@{([
+chartype closing@})]
+chartype punctuation@,;:.
+chartype suppress@\[ha]\[ti]
+.TE
 .RE
 .
 .
+.P
+.I @g@eqn
+assigns all other ordinary and special
+.I roff
+characters,
+including numerals 0\[en]9,
+the
+.B ordinary
+type.
+.
+.\" XXX: Talk about lowercase Greek letters once our story is straight.
+.\" See Savannah #64231.
+.
+.
 .\" ====================================================================
 .SS Primitives
 .\" ====================================================================