Yet another round of improvements to manual font selection.

Unify handling of \f and .ft.
Support \f4 (bold+italic).
Support ".ft BI" and ".ft CW" for terminal output.
Support the .ft request in HTML output.
Reject the bogus fonts \f(C1, \f(C2, \f(C3, and \f(CP.
In regress.pl, only strip leading whitespace in math mode.

1 files changed, 79 insertions, 43 deletions

diff --git a/roff.7 b/roff.7
index 7541c549..3ccf1093 100644
--- a/roff.7
+++ b/roff.7
@@ -1,4 +1,4 @@
-.\"	$Id: roff.7,v 1.108 2018/12/15 19:30:26 schwarze Exp $
+.\"	$Id: roff.7,v 1.109 2018/12/16 00:17:02 schwarze Exp $
 .\"
 .\" Copyright (c) 2010, 2011, 2012 Kristaps Dzonsons <kristaps@bsd.lv>
 .\" Copyright (c) 2010-2018 Ingo Schwarze <schwarze@openbsd.org>
@@ -15,7 +15,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: December 15 2018 $
+.Dd $Mdocdate: December 16 2018 $
 .Dt ROFF 7
 .Os
 .Sh NAME
@@ -132,20 +132,73 @@ One-letter backslash escape.
 See
 .Xr mandoc_char 7
 for a complete list.
-.Ss Text Decoration
-Terms may be text-decorated using the
-.Sq \ef
-escape followed by an indicator: B (bold), I (italic), R (regular), or P
-(revert to previous mode).
-A numerical representation 3, 2, or 1 (bold, italic, and regular,
-respectively) may be used instead.
-The indicator or numerical representative may be preceded by C
-(constant-width), which is ignored.
-.Pp
-The two-character indicator
-.Sq BI
-requests a font that is both bold and italic.
-It may not be portable to old roff implementations.
+.Ss Font Selection
+In
+.Xr mdoc 7
+and
+.Xr man 7
+documents, fonts are usually selected with macros.
+The
+.Ic \ef
+escape sequence and the
+.Ic \&ft
+request can be used to manually change the font,
+but this is not recommended in
+.Xr mdoc 7
+documents.
+Such manual font changes are overridden by many subsequent macros.
+.Pp
+The following fonts are supported:
+.Pp
+.Bl -tag -width CW -offset indent -compact
+.It Cm B
+Bold font.
+.It Cm BI
+A font that is both bold and italic.
+.It Cm CB
+Bold constant width font.
+Same as
+.Cm B
+in terminal output.
+.It Cm CI
+Italic constant width font.
+Same as
+.Cm I
+in terminal output.
+.It Cm CR
+Regular constant width font.
+Same as
+.Cm R
+in terminal output.
+.It Cm CW
+An alias for
+.Cm CR .
+.It Cm I
+Italic font.
+.It Cm P
+Return to the previous font.
+If a macro caused a font change since the last
+.Ic \ef
+eascape sequence or
+.Ic \&ft
+request, this returns to the font before the last font change in
+the macro rather than to the font before the last manual font change.
+.It Cm R
+Roman font.
+This is the default font.
+.It Cm 1
+An alias for
+.Cm R .
+.It Cm 2
+An alias for
+.Cm I .
+.It Cm 3
+An alias for
+.Cm B .
+.It Cm 4
+An alias for
+.Cm BI .
+.El
 .Pp
 Examples:
 .Bl -tag -width Ds -offset indent -compact
@@ -156,12 +209,6 @@ Write in \fIitalic\fP, then return to previous font mode.
 .It Li \ef(BIbold italic\efP
 Write in \f(BIbold italic\fP, then return to previous font mode.
 .El
-.Pp
-Text decoration is
-.Em not
-recommended for
-.Xr mdoc 7 ,
-which encourages semantic annotation.
 .Ss Whitespace
 Whitespace consists of the space character.
 In text lines, whitespace is preserved within a line.
@@ -890,27 +937,12 @@ This is a Heirloom extension and currently ignored.
 Conditionally define a special font.
 This is a groff extension and currently ignored.
 .It Ic \&ft Op Ar font
-Change the font.
-The following
+Change the font; see
+.Sx Font Selection .
+The
 .Ar font
-arguments are supported:
-.Bl -tag -width 4n -offset indent
-.It Cm B , BI , CB , 3 , 4
-switches to
-.Sy bold
-font
-.It Cm I , CI , 2
-switches to
-.Em underlined
-font
-.It Cm R , CR , CW , 1
-switches to normal font
-.It Cm P No "or no argument"
-switches back to the previous font
-.El
-.Pp
-This request takes effect only locally and may be overridden
-by macros and escape sequences.
+argument defaults to
+.Cm P .
 .It Ic \&ftr Ar newname Op Ar oldname
 Translate font name.
 This is a groff extension and currently ignored.
@@ -2006,11 +2038,15 @@ and
 Switch to the font
 .Ar name ,
 see
-.Sx Text Decoration .
+.Sx Font Selection .
 For short names, there are variants
 .Ic \ef Ns Ar c
 and
 .Ic \ef( Ns Ar cc .
+An empty name
+.Ic \ef[]
+defaults to
+.Ic \efP .
 .It Ic \eg[ Ns Ar name Ns Ic \&]
 Interpolate the format of a number register; ignored by
 .Xr mandoc 1 .