[groff] 12/46: tmac/an-ext.tmac: Define nroff-mode value for mC.

[G. Branden Robinson]

gbranden pushed a commit to branch master
in repository groff.

commit b475f148e5eb689fc3f58e9507039173cc9e27a3
Author: G. Branden Robinson <g.branden.robinson@gmail.com>
AuthorDate: Fri Dec 2 03:17:21 2022 -0600

    tmac/an-ext.tmac: Define nroff-mode value for mC.
    
    * tmac/an-ext.tmac: Define `mC` string (constant-width typeface used by
      `EX`/`EE` macros) as `R` in nroff mode.  Thanks to Russ Allbery for
      prompting me to think more about the limitations of Solaris troff.
      Implementations do varying things with the "previous" font restored by
      `\fP` or an unargumented `.ft` if a requested font is not found.
    
    >     \fBsomething\fP \f(CW-\fP something else
    >
    > [Y]ou will discover that "something else" is in bold because
    > the second \fP reverts to the "previous" font, which nroff
    > thinks is \fB becuase \f(CW was ignored.  (Just tested now on
    > a Solaris 10 host.)  Pod::Man has fairly elaborate workarounds
    > for this bug.
---
 ChangeLog        | 9 +++++++++
 tmac/an-ext.tmac | 1 +
 2 files changed, 10 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 85a6faf0d..647084aaf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2022-12-02  G. Branden Robinson <g.branden.robinson@gmail.com>
+
+       * tmac/an-ext.tmac: Define `mC` string (constant-width typeface
+       used by `EX`/`EE` macros) as `R` in nroff mode.  Thanks to
+       Russ Allbery for prompting me to think more about the
+       limitations of Solaris troff.  Implementations do varying
+       things with the "previous" font restored by `\fP` or an
+       unargumented `.ft` if a requested font is not found.
+
 2022-11-30  G. Branden Robinson <g.branden.robinson@gmail.com>
 
        [tbl]: Fix Savannah #63449.
diff --git a/tmac/an-ext.tmac b/tmac/an-ext.tmac
index a4b48b9da..723504b5c 100644
--- a/tmac/an-ext.tmac
+++ b/tmac/an-ext.tmac
@@ -29,6 +29,7 @@
 .
 .\" Define this to your implementation's constant-width typeface.
 .ds mC CW
+.if n .ds mC R
 .
 .\" In AT&T troff, there was no register exposing the hyphenation mode,
 .\" and no way to save and restore it.  Set this to a reasonable value