===================================================================
RCS file: /cvs/mandoc/mandoc.1,v
retrieving revision 1.14
retrieving revision 1.92
diff -u -p -r1.14 -r1.92
--- mandoc/mandoc.1	2009/04/12 19:19:57	1.14
+++ mandoc/mandoc.1	2011/09/18 14:14:15	1.92
@@ -1,136 +1,113 @@
-.\" $Id: mandoc.1,v 1.14 2009/04/12 19:19:57 kristaps Exp $
+.\"	$Id: mandoc.1,v 1.92 2011/09/18 14:14:15 schwarze Exp $
 .\"
-.\" Copyright (c) 2009 Kristaps Dzonsons <kristaps@openbsd.org>
+.\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 .\"
 .\" Permission to use, copy, modify, and distribute this software for any
-.\" purpose with or without fee is hereby granted, provided that the
-.\" above copyright notice and this permission notice appear in all
-.\" copies.
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
 .\"
-.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
-.\" WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
-.\" WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
-.\" AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
-.\" DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
-.\" PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
-.\" TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
-.\" PERFORMANCE OF THIS SOFTWARE.
+.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: April 12 2009 $
+.Dd $Mdocdate: September 18 2011 $
 .Dt MANDOC 1
 .Os
-.\" SECTION
 .Sh NAME
 .Nm mandoc
 .Nd format and display UNIX manuals
-.\" SECTION
 .Sh SYNOPSIS
 .Nm mandoc
 .Op Fl V
-.Op Fl f Ns Ar option...
 .Op Fl m Ns Ar format
-.Op Fl W Ns Ar err...
+.Op Fl O Ns Ar option
 .Op Fl T Ns Ar output
-.Op Ar infile...
-.\" SECTION
+.Op Fl W Ns Ar level
+.Op Ar
 .Sh DESCRIPTION
 The
 .Nm
-utility formats 
+utility formats
 .Ux
-manual pages for display.  The arguments are as follows:
-.Bl -tag -width XXXXXXXXXXXX
-.\" ITEM
-.It Fl f Ns Ar option...
-Override default compiler behaviour.  See 
-.Sx Compiler Options
-for details.
-.\" ITEM
-.It Fl m
-Input format.  See
+manual pages for display.
+The arguments are as follows:
+.Bl -tag -width Ds
+.It Fl m Ns Ar format
+Input format.
+See
 .Sx Input Formats
-for available formats.  Defaults to
-.Fl m Ns Ar andoc .
-.\" ITEM
-.It Fl T
-Output format.  See
+for available formats.
+Defaults to
+.Fl m Ns Cm andoc .
+.It Fl O Ns Ar option
+Comma-separated output options.
+.It Fl T Ns Ar output
+Output format.
+See
 .Sx Output Formats
-for available formats.  Defaults to
-.Fl T Ns Ar ascii .
-.\" ITEM
+for available formats.
+Defaults to
+.Fl T Ns Cm ascii .
 .It Fl V
 Print version and exit.
-.\" ITEM
-.It Fl W Ns Ar err...
-Print warning messages.  May be set to 
-.Fl W Ns Ar all
-for all warnings, 
-.Ar compat
-for groff/troff-compatibility warnings, or
-.Ar syntax
-for syntax warnings.  If
-.Fl W Ns Ar error 
-is specified, warnings are considered errors and cause utility
-termination.  Multiple 
-.Fl W
-arguments may be comma-separated, such as
-.Fl W Ns Ar error,all .
-.\" ITEM
-.It Ar infile...
-Read input from zero or more
-.Ar infile .
-If unspecified, reads from stdin.  If multiple files are specified,
+.It Fl W Ns Ar level
+Specify the minimum message
+.Ar level
+to be reported on the standard error output and to affect the exit status.
+The
+.Ar level
+can be
+.Cm warning ,
+.Cm error ,
+or
+.Cm fatal .
+The default is
+.Fl W Ns Cm fatal ;
+.Fl W Ns Cm all
+is an alias for
+.Fl W Ns Cm warning .
+See
+.Sx EXIT STATUS
+and
+.Sx DIAGNOSTICS
+for details.
+.Pp
+The special option
+.Fl W Ns Cm stop
+tells
 .Nm
+to exit after parsing a file that causes warnings or errors of at least
+the requested level.
+No formatted output will be produced from that file.
+If both a
+.Ar level
+and
+.Cm stop
+are requested, they can be joined with a comma, for example
+.Fl W Ns Cm error , Ns Cm stop .
+.It Ar file
+Read input from zero or more files.
+If unspecified, reads from stdin.
+If multiple files are specified,
+.Nm
 will halt with the first failed parse.
 .El
-.\" PARAGRAPH
 .Pp
-By default, 
-.Nm 
-reads 
+By default,
+.Nm
+reads
 .Xr mdoc 7
 or
 .Xr man 7
 text from stdin, implying
-.Fl m Ns Ar andoc ,
-and prints 78-column backspace-encoded output to stdout as if
-.Fl T Ns Ar ascii
-were provided.
-.\" PARAGRAPH
-.Pp
-.Ex -std mandoc
-.\" SUB-SECTION
-.Ss Punctuation
-If punctuation is set apart from words, such as in the phrase
-.Dq to be \&, or not to be ,
-it's processed by
-.Nm
-according to the following rules.  Opening punctuation
-.Po
-.Sq \&( , 
-.Sq \&[ , 
-and
-.Sq \&{
-.Pc 
-is not followed by a space. Closing punctuation
-.Po
-.Sq \&. , 
-.Sq \&, , 
-.Sq \&; , 
-.Sq \&: , 
-.Sq \&? , 
-.Sq \&! , 
-.Sq \&) , 
-.Sq \&] 
-and
-.Sq \&}
-.Pc 
-is not preceeded by whitespace.
-.Pp
-If the input is
-.Xr mdoc 7 ,
-these rules are also applied to macro arguments when appropriate.
-.\" SUB-SECTION
+.Fl m Ns Cm andoc ,
+and produces
+.Fl T Ns Cm ascii
+output.
 .Ss Input Formats
 The
 .Nm
@@ -139,153 +116,505 @@ utility accepts
 and
 .Xr man 7
 input with
-.Fl m Ns Ar doc
+.Fl m Ns Cm doc
 and
-.Fl m Ns Ar an ,
-respectively.  The
+.Fl m Ns Cm an ,
+respectively.
+The
 .Xr mdoc 7
 format is
 .Em strongly
-recommended; 
+recommended;
 .Xr man 7
 should only be used for legacy manuals.
 .Pp
 A third option,
-.Fl m Ns Ar andoc ,
+.Fl m Ns Cm andoc ,
 which is also the default, determines encoding on-the-fly: if the first
-non-comment macro is 
-.Sq \&.Dd
+non-comment macro is
+.Sq \&Dd
 or
-.Sq \&.Dt ,
-the 
+.Sq \&Dt ,
+the
 .Xr mdoc 7
 parser is used; otherwise, the
 .Xr man 7
 parser is used.
 .Pp
 If multiple
-files are specified with 
-.Fl m Ns Ar andoc , 
-each has its file-type determined this way.  If multiple files are
+files are specified with
+.Fl m Ns Cm andoc ,
+each has its file-type determined this way.
+If multiple files are
 specified and
-.Fl m Ns Ar doc
+.Fl m Ns Cm doc
 or
-.Fl m Ns Ar an
+.Fl m Ns Cm an
 is specified, then this format is used exclusively.
-.\" .Pp
-.\" The following escape sequences are recognised, although the per-format
-.\" compiler may not allow certain sequences.
-.\" .Bl -tag -width Ds -offset XXXX
-.\" .It \efX
-.\" sets the font mode to X (B, I, R or P, where P resets the font)
-.\" .It \eX, \e(XX, \e[XN]
-.\" queries the special-character table for a corresponding symbol
-.\" .It \e*X, \e*(XX, \e*[XN]
-.\" deprecated special-character format
-.\" .El
-.\" SUB-SECTION
 .Ss Output Formats
 The
 .Nm
 utility accepts the following
 .Fl T
-arguments:
-.Bl -tag -width XXXXXXXXXXXX 
-.It Fl T Ns Ar ascii
-Produce 7-bit ASCII output, backspace-encoded for bold and underline
-styles.  This is the default.
-.It Fl T Ns Ar tree
-Produce an indented parse tree.
-.It Fl T Ns Ar lint
+arguments, which correspond to output modes:
+.Bl -tag -width Ds
+.It Fl T Ns Cm utf8
+Encode output in the UTF\-8 multi-byte format.
+See
+.Sx UTF\-8 Output .
+.It Fl T Ns Cm locale
+Encode output using the current locale.
+See
+.Sx Locale Output .
+.It Fl T Ns Cm ascii
+Produce 7-bit ASCII output.
+This is the default.
+See
+.Sx ASCII Output .
+.It Fl T Ns Cm html
+Produce strict CSS1/HTML-4.01 output.
+See
+.Sx HTML Output .
+.It Fl T Ns Cm lint
 Parse only: produce no output.
+Implies
+.Fl W Ns Cm warning .
+.It Fl T Ns Cm man
+Produce output in
+.Xr man 7
+format; only useful when applied to
+.Fl m Ns Cm doc
+input.
+.It Fl T Ns Cm pdf
+Produce PDF output.
+See
+.Sx PDF Output .
+.It Fl T Ns Cm ps
+Produce PostScript output.
+See
+.Sx PostScript Output .
+.It Fl T Ns Cm tree
+Produce an indented parse tree.
+.It Fl T Ns Cm xhtml
+Produce strict CSS1/XHTML-1.0 output.
+See
+.Sx XHTML Output .
 .El
 .Pp
 If multiple input files are specified, these will be processed by the
 corresponding filter in-order.
-.\" SUB-SECTION
-.Ss Compiler Options
-Default compiler behaviour may be overriden with the
-.Fl f
-flag.
-.Bl -tag -width XXXXXXXXXXXXXX 
-.It Fl f Ns Ar ign-scope
-When rewinding the scope of a block macro, forces the compiler to ignore
-scope violations.  This can seriously mangle the resulting tree.
-.Pq mdoc only
-.It Fl f Ns Ar ign-escape
-Ignore invalid escape sequences.
-.It Fl f Ns Ar ign-macro
-Ignore unknown macros at the start of input lines (default for 
-.Xr man 7
-parsing).
-.It Fl f Ns Ar no-ign-macro
-Do not ignore unknown macros at the start of input lines (default for 
-.Xr mdoc 7
-parsing).
+.Ss UTF\-8 Output
+Use
+.Fl T Ns Cm utf8
+to force a UTF\-8 locale.
+See
+.Sx Locale Output
+for details and options.
+.Ss Locale Output
+Locale-depending output encoding is triggered with
+.Fl T Ns Cm locale .
+This option is not available on all systems: systems without locale
+support, or those whose internal representation is not natively UCS-4,
+will fall back to
+.Fl T Ns Cm ascii .
+See
+.Sx ASCII Output
+for font style specification and available command-line arguments.
+.Ss ASCII Output
+Output produced by
+.Fl T Ns Cm ascii ,
+which is the default, is rendered in standard 7-bit ASCII documented in
+.Xr ascii 7 .
+.Pp
+Font styles are applied by using back-spaced encoding such that an
+underlined character
+.Sq c
+is rendered as
+.Sq _ Ns \e[bs] Ns c ,
+where
+.Sq \e[bs]
+is the back-space character number 8.
+Emboldened characters are rendered as
+.Sq c Ns \e[bs] Ns c .
+.Pp
+The special characters documented in
+.Xr mandoc_char 7
+are rendered best-effort in an ASCII equivalent.
+If no equivalent is found,
+.Sq \&?
+is used instead.
+.Pp
+Output width is limited to 78 visible columns unless literal input lines
+exceed this limit.
+.Pp
+The following
+.Fl O
+arguments are accepted:
+.Bl -tag -width Ds
+.It Cm width Ns = Ns Ar width
+The output width is set to
+.Ar width ,
+which will normalise to \(>=60.
 .El
-.\" PARAGRAPH
+.Ss HTML Output
+Output produced by
+.Fl T Ns Cm html
+conforms to HTML-4.01 strict.
 .Pp
-As with the
+The
+.Pa example.style.css
+file documents style-sheet classes available for customising output.
+If a style-sheet is not specified with
+.Fl O Ns Ar style ,
+.Fl T Ns Cm html
+defaults to simple output readable in any graphical or text-based web
+browser.
+.Pp
+Special characters are rendered in decimal-encoded UTF\-8.
+.Pp
+The following
+.Fl O
+arguments are accepted:
+.Bl -tag -width Ds
+.It Cm includes Ns = Ns Ar fmt
+The string
+.Ar fmt ,
+for example,
+.Ar ../src/%I.html ,
+is used as a template for linked header files (usually via the
+.Sq \&In
+macro).
+Instances of
+.Sq \&%I
+are replaced with the include filename.
+The default is not to present a
+hyperlink.
+.It Cm man Ns = Ns Ar fmt
+The string
+.Ar fmt ,
+for example,
+.Ar ../html%S/%N.%S.html ,
+is used as a template for linked manuals (usually via the
+.Sq \&Xr
+macro).
+Instances of
+.Sq \&%N
+and
+.Sq %S
+are replaced with the linked manual's name and section, respectively.
+If no section is included, section 1 is assumed.
+The default is not to
+present a hyperlink.
+.It Cm style Ns = Ns Ar style.css
+The file
+.Ar style.css
+is used for an external style-sheet.
+This must be a valid absolute or
+relative URI.
+.El
+.Ss PostScript Output
+PostScript
+.Qq Adobe-3.0
+Level-2 pages may be generated by
+.Fl T Ns Cm ps .
+Output pages default to letter sized and are rendered in the Times font
+family, 11-point.
+Margins are calculated as 1/9 the page length and width.
+Line-height is 1.4m.
+.Pp
+Special characters are rendered as in
+.Sx ASCII Output .
+.Pp
+The following
+.Fl O
+arguments are accepted:
+.Bl -tag -width Ds
+.It Cm paper Ns = Ns Ar name
+The paper size
+.Ar name
+may be one of
+.Ar a3 ,
+.Ar a4 ,
+.Ar a5 ,
+.Ar legal ,
+or
+.Ar letter .
+You may also manually specify dimensions as
+.Ar NNxNN ,
+width by height in millimetres.
+If an unknown value is encountered,
+.Ar letter
+is used.
+.El
+.Ss PDF Output
+PDF-1.1 output may be generated by
+.Fl T Ns Cm pdf .
+See
+.Sx PostScript Output
+for
+.Fl O
+arguments and defaults.
+.Ss XHTML Output
+Output produced by
+.Fl T Ns Cm xhtml
+conforms to XHTML-1.0 strict.
+.Pp
+See
+.Sx HTML Output
+for details; beyond generating XHTML tags instead of HTML tags, these
+output modes are identical.
+.Sh EXIT STATUS
+The
+.Nm
+utility exits with one of the following values, controlled by the message
+.Ar level
+associated with the
 .Fl W
-flag, multiple
-.Fl f
-options may be grouped and delimited with a comma.  Using
-.Fl f Ns Ar ign-scope,ign-escape ,
-for example, will try to ignore scope and character-escape errors.
-.\" SECTION
+option:
+.Pp
+.Bl -tag -width Ds -compact
+.It 0
+No warnings or errors occurred, or those that did were ignored because
+they were lower than the requested
+.Ar level .
+.It 2
+At least one warning occurred, but no error, and
+.Fl W Ns Cm warning
+was specified.
+.It 3
+At least one parsing error occurred, but no fatal error, and
+.Fl W Ns Cm error
+or
+.Fl W Ns Cm warning
+was specified.
+.It 4
+A fatal parsing error occurred.
+.It 5
+Invalid command line arguments were specified.
+No input files have been read.
+.It 6
+An operating system error occurred, for example memory exhaustion or an
+error accessing input files.
+Such errors cause
+.Nm
+to exit at once, possibly in the middle of parsing or formatting a file.
+.El
+.Pp
+Note that selecting
+.Fl T Ns Cm lint
+output mode implies
+.Fl W Ns Cm warning .
 .Sh EXAMPLES
 To page manuals to the terminal:
-.\" PARAGRAPH
 .Pp
-.D1 % mandoc \-Wall,error mandoc.1 2>&1 | less
+.Dl $ mandoc \-Wall,stop mandoc.1 2\*(Gt&1 | less
+.Dl $ mandoc mandoc.1 mdoc.3 mdoc.7 | less
 .Pp
-.D1 % mandoc mandoc.1 mdoc.3 mdoc.7 | less
-.\" SECTION
-.Sh SEE ALSO
-.Xr mandoc_char 7 ,
-.Xr mdoc 7 ,
+To produce HTML manuals with
+.Ar style.css
+as the style-sheet:
+.Pp
+.Dl $ mandoc \-Thtml -Ostyle=style.css mdoc.7 \*(Gt mdoc.7.html
+.Pp
+To check over a large set of manuals:
+.Pp
+.Dl $ mandoc \-Tlint `find /usr/src -name \e*\e.[1-9]`
+.Pp
+To produce a series of PostScript manuals for A4 paper:
+.Pp
+.Dl $ mandoc \-Tps \-Opaper=a4 mdoc.7 man.7 \*(Gt manuals.ps
+.Pp
+Convert a modern
+.Xr mdoc 7
+manual to the older
 .Xr man 7
-.\" 
-.Sh AUTHORS
-The
-.Nm
-utility was written by 
-.An Kristaps Dzonsons Aq kristaps@openbsd.org .
-.\" SECTION
-.Sh CAVEATS
-The 
-.Nm
-utility in
-.Fl T Ns Ar ascii
-mode doesn't yet know how to display the following:
+format, for use on systems lacking an
+.Xr mdoc 7
+parser:
 .Pp
-.Bl -bullet -compact
-.It
-The \-hang 
-.Sq \&.Bl
-list is not yet supported.
+.Dl $ mandoc \-Tman foo.mdoc \*(Gt foo.man
+.Sh DIAGNOSTICS
+Standard error messages reporting parsing errors are prefixed by
+.Pp
+.Sm off
+.D1 Ar file : line : column : \ level :
+.Sm on
+.Pp
+where the fields have the following meanings:
+.Bl -tag -width "column"
+.It Ar file
+The name of the input file causing the message.
+.It Ar line
+The line number in that input file.
+Line numbering starts at 1.
+.It Ar column
+The column number in that input file.
+Column numbering starts at 1.
+If the issue is caused by a word, the column number usually
+points to the first character of the word.
+.It Ar level
+The message level, printed in capital letters.
 .El
 .Pp
-Other macros still aren't supported by virtue of nobody complaining
-about their absence.  Please report any omissions: this is a work in
-progress.
+Message levels have the following meanings:
+.Bl -tag -width "warning"
+.It Cm fatal
+The parser is unable to parse a given input file at all.
+No formatted output is produced from that input file.
+.It Cm error
+An input file contains syntax that cannot be safely interpreted,
+either because it is invalid or because
+.Nm
+does not implement it yet.
+By discarding part of the input or inserting missing tokens,
+the parser is able to continue, and the error does not prevent
+generation of formatted output, but typically, preparing that
+output involves information loss, broken document structure
+or unintended formatting.
+.It Cm warning
+An input file uses obsolete, discouraged or non-portable syntax.
+All the same, the meaning of the input is unambiguous and a correct
+rendering can be produced.
+Documents causing warnings may render poorly when using other
+formatting tools instead of
+.Nm .
+.El
 .Pp
-The following list documents differences between traditional
-.Xr nroff 1
-output and
-.Nm :
+Messages of the
+.Cm warning
+and
+.Cm error
+levels are hidden unless their level, or a lower level, is requested using a
+.Fl W
+option or
+.Fl T Ns Cm lint
+output mode.
 .Pp
+The
+.Nm
+utility may also print messages related to invalid command line arguments
+or operating system errors, for example when memory is exhausted or
+input files cannot be read.
+Such messages do not carry the prefix described above.
+.Sh COMPATIBILITY
+This section summarises
+.Nm
+compatibility with GNU troff.
+Each input and output format is separately noted.
+.Ss ASCII Compatibility
 .Bl -bullet -compact
-.It 
-A list of display following
-.Sq \&.Ss
+.It
+Unrenderable unicode codepoints specified with
+.Sq \e[uNNNN]
+escapes are printed as
+.Sq \&?
+in mandoc.
+In GNU troff, these raise an error.
+.It
+The
+.Sq \&Bd \-literal
+and
+.Sq \&Bd \-unfilled
+macros of
+.Xr mdoc 7
+in
+.Fl T Ns Cm ascii
+are synonyms, as are \-filled and \-ragged.
+.It
+In historic GNU troff, the
+.Sq \&Pa
+.Xr mdoc 7
+macro does not underline when scoped under an
+.Sq \&It
+in the FILES section.
+This behaves correctly in
+.Nm .
+.It
+A list or display following the
+.Sq \&Ss
+.Xr mdoc 7
+macro in
+.Fl T Ns Cm ascii
 does not assert a prior vertical break, just as it doesn't with
-.Sq \&.Sh .
+.Sq \&Sh .
 .It
-Special characters don't follow the current font style.
-.\" LIST-ITEM
+The
+.Sq \&na
+.Xr man 7
+macro in
+.Fl T Ns Cm ascii
+has no effect.
 .It
-The \-literal and \-unfilled 
-.Sq \&.Bd
-displays types are synonyms, as are \-filled and \-ragged.
+Words aren't hyphenated.
 .El
+.Ss HTML/XHTML Compatibility
+.Bl -bullet -compact
+.It
+The
+.Sq \efP
+escape will revert the font to the previous
+.Sq \ef
+escape, not to the last rendered decoration, which is now dictated by
+CSS instead of hard-coded.
+It also will not span past the current scope,
+for the same reason.
+Note that in
+.Sx ASCII Output
+mode, this will work fine.
+.It
+The
+.Xr mdoc 7
+.Sq \&Bl \-hang
+and
+.Sq \&Bl \-tag
+list types render similarly (no break following overreached left-hand
+side) due to the expressive constraints of HTML.
+.It
+The
+.Xr man 7
+.Sq IP
+and
+.Sq TP
+lists render similarly.
+.El
+.Sh SEE ALSO
+.Xr eqn 7 ,
+.Xr man 7 ,
+.Xr mandoc_char 7 ,
+.Xr mdoc 7 ,
+.Xr roff 7 ,
+.Xr tbl 7
+.Sh AUTHORS
+The
+.Nm
+utility was written by
+.An Kristaps Dzonsons ,
+.Mt kristaps@bsd.lv .
+.Sh CAVEATS
+In
+.Fl T Ns Cm html
+and
+.Fl T Ns Cm xhtml ,
+the maximum size of an element attribute is determined by
+.Dv BUFSIZ ,
+which is usually 1024 bytes.
+Be aware of this when setting long link
+formats such as
+.Fl O Ns Cm style Ns = Ns Ar really/long/link .
+.Pp
+Nesting elements within next-line element scopes of
+.Fl m Ns Cm an ,
+such as
+.Sq br
+within an empty
+.Sq B ,
+will confuse
+.Fl T Ns Cm html
+and
+.Fl T Ns Cm xhtml
+and cause them to forget the formatting of the prior next-line scope.
+.Pp
+The
+.Sq \(aq
+control character is an alias for the standard macro control character
+and does not emit a line-break as stipulated in GNU troff.