troff.man

早期freebsd实现

.B n
to 1.
.TP
.B .backtrace
Print a backtrace of the input stack on stderr.
.TP
.B .break
Break out of a while loop.
See also the
.B while
and
.B continue
requests.
Be sure not to confuse this with the
.B br
request.
.TP
.BI .cflags\  n\ c1\ c2\|.\|.\|.
Characters
.IR c1 ,
.IR c2 ,\|.\|.\|.
have properties determined by
.IR n ,
which is ORed from the following:
.RS
.TP
1
the character ends sentences
(initially characters
.B .?!
have this property);
.TP
2
lines can be broken before the character
(initially no characters have this property);
.TP
4
lines can be broken after the character
(initially characters
.B \-\e(hy\e(em
have this property);
.TP
8
the character overlaps horizontally
(initially characters
.B \e(ul\e(rn\e(ru
have this property);
.TP
16
the character overlaps vertically
(initially character
.B \e(br
has this property);
.TP
32
an end of sentence character followed by any number of characters
with this property will be treated
as the end of a sentence if followed by a newline or two spaces;
in other words
the character is transparent for the purposes of end of sentence
recognition;
this is the same as having a zero space factor in \*(tx
(initially characters
.B \(ts')]*\e(dg\e(rq
have this property).
.RE
.TP
.BI .char\  c\ string
Define character
.I c
to be
.IR string .
Every time character
.I c
needs to be printed,
.I string
will be processed in a temporary environment and the result
will be wrapped up into a single object.
Compatibility mode will be turned off
and the escape character will be set to
.B \e
while
.I string
is being processed.
Any emboldening, constant spacing or track kerning will be applied
to this object rather than to individual characters in
.IR string .
A character defined by this request can be used just like
a normal character provided by the output device.
In particular other characters can be translated to it
with the
.B tr
request;
it can be made the leader character by the
.B lc
request;
repeated patterns can be drawn with the character using the
.B \el
and
.B \eL
escape sequences;
words containing the character can be hyphenated
correctly, if the
.B hcode
request is used to give the character a hyphenation code.
There is a special anti-recursion feature: 
use of character within the character's definition
will be handled like normal characters not defined with
.BR char .
A character definition can be removed with the
.B rchar
request.
.TP
.BI .chop\  xx
Chop the last character off macro, string, or diversion
.IR xx .
This is useful for removing the newline from the end of diversions
that are to be interpolated as strings.
.TP
.BI .close\  stream
Close the stream named
.IR stream ;
.I stream
will no longer be an acceptable argument to the
.B write
request.
See the
.B open
request.
.TP
.B .continue
Finish the current iteration of a while loop.
See also the
.B while
and
.B break
requests.
.TP
.BI .cp\  n
If
.I n
is non-zero or missing, enable compatibility mode, otherwise
disable it.
In compatibility mode, long names are not recognised, and the
incompatibilities caused by long names do not arise.
.TP
.BI .do\  xxx
Interpret
.I .xxx
with compatibility mode disabled.
For example,
.RS
.IP
.B
\&.do fam T
.LP
would have the same effect as
.IP
.B
\&.fam T
.LP
except that it would work even if compatibility mode had been enabled.
Note that the previous compatibility mode is restored before any files
sourced by
.I xxx
are interpreted.
.RE
.TP
.BI .fam\  xx
Set the current font family to
.IR xx .
The current font family is part of the current environment.
See the description of the
.B sty
request for more information on font families.
.TP
.BI .fspecial\  f\ s1\ s2\|.\|.\|.
When the current font is
.IR f ,
fonts
.IR s1 ,
.IR s2 ,\|.\|.\|.
will be special, that is, they will searched for characters not in
the current font.
Any fonts specified in the
.B special
request will be searched before fonts specified in the
.B fspecial
request.
.TP
.BI .ftr\  f\ g
Translate font
.I f
to
.IR g .
Whenever a font named
.I f
is referred to in
.B \ef
escape sequence,
or in the
.BR ft ,
.BR ul ,
.BR bd ,
.BR cs ,
.BR tkf ,
.BR special ,
.BR fspecial ,
.BR fp ,
or
.BR sty
requests,
font
.I g
will be used.
If
.I g
is missing,
or equal to
.I f
then font
.I f
will not be translated.
.TP
.BI .hcode \ c1\ code1\ c2\ code2\|.\|.\|.
Set the hyphenation code of character
.I c1
to
.I code1
and that of
.I c2
to
.IR code2 .
A hyphenation code must be a single input
character (not a special character) other than a digit or a space.
Initially each lower-case letter has a hyphenation code, which
is itself, and each upper-case letter has a hyphenation code
which is the lower case version of itself.
See also the
.B hpf
request.
.TP
.BI .hla\  lang
Set the current hyphenation language to
.IR lang .
Hyphenation exceptions specified with the
.B hw
request and hyphenation patterns specified with the
.B hpf
request are both associated with the current hyphenation language.
The
.B hla
request is usually invoked by the
.B troffrc
file.
.TP
.BI .hlm\  n
Set the maximum number of consecutive hyphenated lines to
.IR n .
If
.I n
is negative, there is no maximum.
The default value is \-1.
This value is associated with the current environment.
Only lines output from an environment count towards the maximum associated
with that environment.
Hyphens resulting from
.B \e%
are counted; explicit hyphens are not.
.TP
.BI .hpf\  file
Read hyphenation patterns from
.IR file ;
this will be searched for in the same way that
.BI tmac. name
is searched for when the
.BI \-m name
option is specified.
It should have the same format as the argument to
the \epatterns primitive in \*(tx;
the letters appearing in this file are interpreted as hyphenation
codes.
A
.B %
character in the patterns file introduces a comment that continues
to the end of the line.
The set of hyphenation patterns is associated with the current language
set by the
.B hla
request.
The
.B hpf
request
is usually invoked by the
.B troffrc
file.
.TP
.BI .hym\  n
Set the
.I hyphenation margin
to
.IR n :
when the current adjustment mode is not
.BR b ,
the line will not be hyphenated if the line is no more than
.I n
short.
The default hyphenation margin is 0.
The default scaling indicator for this request is
.IR m .
The hyphenation margin is associated with the current environment.
The current hyphenation margin is available in the
.B \en[.hym]
register.
.TP
.BI .hys\  n
Set the
.I hyphenation space
to
.IR n :
when the current adjustment mode is
.B b
don't hyphenate the line if the line can be justified by adding no more than
.I n
extra space to each word space.
The default hyphenation space is 0.
The default scaling indicator for this request is
.BR m .
The hyphenation space is associated with the current environment.
The current hyphenation space is available in the
.B \en[.hys]
register.
.TP
.BI .kern\  n
If
.I n
is non-zero or missing, enable pairwise kerning, otherwise disable it.
.TP
.BI .mso\  file
The same as the
.B so
request except that
.I file
is searched for in the same way that
.BI tmac. name
is searched for when the
.BI \-m name
option is specified.
.TP
.B .nroff
Make the
.B n
built-in condition true
and the
.B t
built-in condition false.
This can be reversed using the
.B troff
request.
.TP
.BI .open\  stream\ filename
Open
.I filename
for writing and associate the stream named
.I stream
with it.
See also the
.B close
and
.B write
requests.
.TP 
.BI .opena\  stream\ filename
Like
.BR open ,
but if
.I filename
exists, append to it instead of truncating it.
.TP
.B .pnr
Print the names and contents of all currently defined number registers
on stderr.
.TP
.B .ptr
Print the names and positions of all traps (not including input line
traps and diversion traps) on stderr.  Empty slots in the page trap
list are printed as well, because they can affect the priority of
subsequently planted traps.
.TP
.BI .rchar\  c1\ c2\|.\|.\|.
Remove the definitions of characters
.IR c1 ,
.IR c2 ,\|.\|.\|.
This undoes the effect of a
.B char
request.
.TP
.B .rj
.TQ
.BI .rj\  n
Right justify the next
.I n
input lines.
Without an argument right justify the next input line.
The number of lines to be right justifed is available in the
.B \en[.rj]
register.
This implicitly does
.BR .ce\ 0 .
The
.B ce
request implicitly does
.BR .rj\ 0 .
.TP
.BI .rnn \ xx\ yy
Rename number register
.I xx
to
.IR yy .
.TP
.BI .shc\  c
Set the soft hyphen character to
.IR c .
If
.I c
is omitted,
the soft hyphen character will be set to the default
.BR \e(hy .
The soft hyphen character is the character which will be inserted
when a word is hyphenated at a line break.
If the soft hyphen character does not exist in the font of the character
immediately preceding a potential break point,
then the line will not be broken at that point.
Neither definitions (specified with the
.B char
request)
nor translations (specified with the
.B tr
request)
are considered when finding the soft hyphen character.
.TP
.BI .shift\  n
In a macro, shift the arguments by
.I n
positions:
argument
.I i
becomes argument
.IR i \- n ;
arguments 1 to
.I n
will no longer be available.
If
.I n
is missing,
arguments will be shifted by 1.
Shifting by negative amounts is currently undefined.
.TP
.BI .special\  s1\ s2\|.\|.\|.
Fonts
.IR s1 ,
.IR s2 ,
are special and will be searched for characters not in the
current font.
.TP
.BI .sty\  n\ f
Associate style
.I f
with font position
.IR n .
A font position can be associated either with a font or
with a style.
The current font is the index of a font position and so is also
either a font or a style.
When it is a style, the font that is actually used is the font the
name of which is the concatenation of the name of the current family
and the name of the current style.
For example, if the current font is 1 and font position 1 is
associated with style
.B R
and the current
font family is
.BR T ,
then font
.BR TR
will be used.
If the current font is not a style, then the current family is ignored.
When the requests
.BR cs ,
.BR bd ,
.BR tkf ,
.BR uf ,
or
.B fspecial
are applied to a style,
then they will instead be applied to the member of the
current family corresponding to that style.
The default family can be set with the
.B \-f
option.
The styles command in the
.SM DESC
file controls which font positions
(if any) are initially associated with styles rather than fonts.
.TP
.BI .tkf\  f\ s1\ n1\ s2\ n2
Enable track kerning for font
.IR f .
When the current font is
.I f
the width of every character will be increased by an amount
between
.I n1
and
.IR n2 ;
when the current point size is less than or equal to
.I s1
the width will be increased by
.IR n1 ;
when it is greater than or equal to
.I s2
the width will be increased by
.IR n2 ;
when the point size is greater than or equal to
.I s1
and less than or equal to
.I s2
the increase in width is a linear function of the point size.
.TP
.BI .trf\  filename
Transparently output the contents of file
.IR filename .
Each line is output as it would be were it preceded by
.BR \e! ;
however, the lines are not subject to copy-mode interpretation.
If the file does not end with a newline, then a newline will
be added.
For example, you can define a macro
.I x
containing the contents of file
.IR f ,
using
.RS
.IP
.BI .di\  x
.br
.BI .trf\  f
.br
.B .di
.LP
Unlike with the
.B cf
request,
the file cannot contain characters such as
.SM NUL
that are not legal troff input characters.
.RE
.TP
.B .trnt abcd
This is the same as the
.B tr
request except that the translations do not apply to text that is
transparently throughput into a diversion with
.BR \e! .
For example,
.RS
.LP
.nf
.ft B
\&.tr ab
\&.di x
\e!.tm a
\&.di
\&.x
.fi
.ft
.LP
will print
.BR b ;
if
.B trnt
is used instead of
.B tr
it will print
.BR a .
.RE
.TP
.B .troff
Make the
.B n
built-in condition false,
and the
.B t
built-in condition true.
This undoes the effect of the
.B nroff
request.
.TP
.BI .vpt\  n
Enable vertical position traps if
.I n
is non-zero, disable them otherwise.
Vertical position traps are traps set by the
.B wh
or
.B dt
requests.
Traps set by the
.B it
request are not vertical position traps.
The parameter that controls whether vertical position traps are enabled
is global.
Initially vertical position traps are enabled.
.TP
.BI .warn\  n
Control warnings.
.I n
is the sum of the numbers associated with each warning that is to be enabled;
all other warnings will be disabled.
The number associated with each warning is listed in the `Warnings' section.
For example,
.B .warn 0
will disable all warnings, and
.B .warn 1
will disable all warnings except that about missing characters.
If
.I n
is not given,
all warnings will be enabled.
.TP
.BI .while \ c\ anything
While condition
.I c
is true, accept
.I anything
as input;
.I c
can be any condition acceptable to an
.B if
request;
.I anything
can comprise multiple lines if the first line starts with
.B \e{
and the last line ends with
.BR \e} .
See also the
.B break
and
.B continue
requests.
.TP
.BI .write\  stream\ anything
Write
.I anything
to the stream named
.IR stream .
.I stream
must previously have been the subject of an
.B open
request.
.I anything
is read in copy mode;
a leading
.B \(ts
will be stripped.
.SS Extended requests
.TP
.BI .cf\  filename
When used in a diversion, this will embed in the diversion an object which,