Introduce the concept of nodes that are semantically transparent:

they are skipped when looking for previous or following high-level
macros.  Examples include roff(7) .ft, .ll, and .ta, mdoc(7) .Sm
and .Tg, and man(7) .DT and .PD.  Use this concept for a variety
of improved decisions in various validators and formatters.

While here,
* remove a few const qualifiers on struct arguments that caused trouble;
* get rid of some more Yoda notation in the vicinity;
* and apply some other stylistic improvements in the vicinity.

I found this class of issues while considering .Tg patches from kn@.

1 files changed, 42 insertions, 0 deletions

diff --git a/regress/mdoc/Fl/spacing.in b/regress/mdoc/Fl/spacing.in
new file mode 100644
index 00000000..6b59478f
--- /dev/null
+++ b/regress/mdoc/Fl/spacing.in
@@ -0,0 +1,42 @@
+.\" $OpenBSD: spacing.in,v 1.1 2020/02/27 01:25:58 schwarze Exp $
+.Dd $Mdocdate: February 27 2020 $
+.Dt FL-SPACING 1
+.Os
+.Sh NAME
+.Nm Fl-spacing
+.Nd horizontal spacing after flag macros
+.Sh DESCRIPTION
+with argument:
+.Fl a
+.Pp
+no next node:
+.Xo Fl Xc suffix
+.Pp
+transparent next node only:
+.Xo Fl
+.Tg transparent1
+.Xc suffix
+.Pp
+following text:
+.Fl
+text
+.Pp
+text after transparent node on the same line:
+.Fl Es < >
+text
+.Pp
+following macro on the same line:
+.Fl Em word
+.Pp
+following macro on the next line:
+.Fl
+.Em word
+.Pp
+following macro on the next line after transparent node on the same line:
+.Fl Es < >
+.Em word
+.Pp
+following macro after transparent node on the next line:
+.Fl
+.Tg transparent3
+.Em word