Return to roff.7 CVS log

Up to [cvsweb.bsd.lv] / mandoc

Fix to make horizontal spanners in the layout be properly printed.
mandoc also now warns (so does tbl(1)) if a horizontal spanner is
specified along with data.

While here, fix up some documentation and uncomment the tbl reference.

.\"	$Id: roff.7,v 1.21 2011/01/04 12:06:21 kristaps Exp $
.\"
.\" Copyright (c) 2010 Kristaps Dzonsons <kristaps@bsd.lv>
.\" Copyright (c) 2010 Ingo Schwarze <schwarze@openbsd.org>
.\"
.\" 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.
.\"
.\" 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: January 4 2011 $
.Dt ROFF 7
.Os
.Sh NAME
.Nm roff
.Nd roff language reference for mandoc
.Sh DESCRIPTION
The
.Nm roff
language is a general purpose text formatting language.
In particular, it serves as the basis for the
.Xr mdoc 7
and
.Xr man 7
manual formatting macro languages.
This manual describes the subset of the
.Nm
language accepted by the
.Xr mandoc 1
utility.
.Pp
Input lines beginning with the control characters
.Sq \&.
or
.Sq \(aq
are parsed for requests and macros.
These define the document structure, change the processing state
and manipulate the formatting.
Some requests and macros also produce formatted output,
while others do not.
.Pp
All other input lines provide free-form text to be printed;
the formatting of free-form text depends on the respective
processing context.
.Sh LANGUAGE SYNTAX
.Nm
documents may contain only graphable 7-bit ASCII characters, the space
character, and, in certain circumstances, the tab character.
To produce other characters in the output, use the escape sequences
documented in the
.Xr mandoc_char 7
manual.
.Pp
All manuals must have
.Ux
line terminators.
.Sh REQUEST SYNTAX
A request or macro line consists of:
.Pp
.Bl -enum -compact
.It
the control character
.Sq \&.
or
.Sq \(aq
at the beginning of the line,
.It
optionally an arbitrary amount of whitespace,
.It
the name of the request or the macro, which is one word of arbitrary
length, terminated by whitespace,
.It
and zero or more arguments delimited by whitespace.
.El
.Pp
Thus, the following request lines are all equivalent:
.Bd -literal -offset indent
\&.ig end
\&.ig    end
\&.   ig end
.Ed
.Sh REQUEST REFERENCE
The
.Xr mandoc 1
.Nm
parser recognizes the following requests.
Note that the
.Nm
language defines many more requests not implemented in
.Xr mandoc 1 .
.Ss \&ad
Set line adjustment mode.
This line-scoped request is intended to have one argument to select
normal, left, right, or center adjustment for subsequent text.
Currently, it is ignored including its arguments,
and the number of arguments is not checked.
.Ss \&am
Append to a macro definition.
The syntax of this request is the same as that of
.Sx \&de .
It is currently ignored by
.Xr mandoc 1 ,
as are its children.
.Ss \&ami
Append to a macro definition, specifying the macro name indirectly.
The syntax of this request is the same as that of
.Sx \&dei .
It is currently ignored by
.Xr mandoc 1 ,
as are its children.
.Ss \&am1
Append to a macro definition, switching roff compatibility mode off
during macro execution.
The syntax of this request is the same as that of
.Sx \&de1 .
It is currently ignored by
.Xr mandoc 1 ,
as are its children.
.Ss \&de
Define a
.Nm
macro.
Its syntax can be either
.Bd -literal -offset indent
.Pf . Cm \&de Ar name
.Ar macro definition
\&..
.Ed
.Pp
or
.Bd -literal -offset indent
.Pf . Cm \&de Ar name Ar end
.Ar macro definition
.Pf . Ar end
.Ed
.Pp
Both forms define or redefine the macro
.Ar name
to represent the
.Ar macro definition ,
which may consist of one or more input lines, including the newline
characters terminating each line, optionally containing calls to
.Nm
requests,
.Nm
macros or high-level macros like
.Xr man 7
or
.Xr mdoc 7
macros, whichever applies to the document in question.
.Pp
Specifying a custom
.Ar end
macro works in the same way as for
.Sx \&ig ;
namely, the call to
.Sq Pf . Ar end
first ends the
.Ar macro definition ,
and after that, it is also evaluated as a
.Nm
request or
.Nm
macro, but not as a high-level macro.
.Pp
The macro can be invoked later using the syntax
.Pp
.D1 Pf . Ar name Op Ar argument Op Ar argument ...
.Pp
Arguments are separated by blank characters and can be quoted
using double-quotes
.Pq Sq \(dq
to allow inclusion of blank characters into arguments.
To include the double-quote character into a quoted argument,
escape it from ending the argument by doubling it.
.Pp
The line invoking the macro will be replaced
in the input stream by the
.Ar macro definition ,
replacing all occurrences of
.No \e\e$ Ns Ar N ,
where
.Ar N
is a digit, by the
.Ar N Ns th Ar argument .
For example,
.Bd -literal -offset indent
\&.de ZN
\efI\e^\e\e$1\e^\efP\e\e$2
\&..
\&.ZN XtFree .
.Ed
.Pp
produces
.Pp
.D1 \efI\e^XtFree\e^\efP.
.Pp
in the input stream, and thus in the output: \fI\^XtFree\^\fP.
.Pp
Since macros and user-defined strings share a common string table,
defining a macro
.Ar name
clobbers the user-defined string
.Ar name ,
and the
.Ar macro definition
can also be printed using the
.Sq \e*
string interpolation syntax described below
.Sx ds ,
but this is rarely useful because every macro definition contains at least
one explicit newline character.
.Pp
In order to prevent endless recursion, both groff and
.Xr mandoc 1
limit the stack depth for expanding macros and strings
to a large, but finite number.
Do not rely on the exact value of this limit.
.Ss \&dei
Define a
.Nm
macro, specifying the macro name indirectly.
The syntax of this request is the same as that of
.Sx \&de .
It is currently ignored by
.Xr mandoc 1 ,
as are its children.
.Ss \&de1
Define a
.Nm
macro that will be executed with
.Nm
compatibility mode switched off during macro execution.
This is a GNU extension not available in traditional
.Nm
implementations and not even in older versions of groff.
Since
.Xr mandoc 1
does not implement
.Nm
compatibility mode at all, it handles this request as an alias for
.Sx \&de .
.Ss \&ds
Define a user-defined string.
Its syntax is as follows:
.Pp
.D1 Pf . Cm \&ds Ar name Oo \(dq Oc Ns Ar string
.Pp
The
.Ar name
and
.Ar string
arguments are space-separated.
If the
.Ar string
begins with a double-quote character, that character will not be part
of the string.
All remaining characters on the input line form the
.Ar string ,
including whitespace and double-quote characters, even trailing ones.
.Pp
The
.Ar string
can be interpolated into subsequent text by using
.No \e* Ns Bq Ar name
for a
.Ar name
of arbitrary length, or \e*(NN or \e*N if the length of
.Ar name
is two or one characters, respectively.
Interpolation can be prevented by escaping the leading backslash;
that is, an asterisk preceded by an even number of backslashes
does not trigger string interpolation.
.Pp
Since user-defined strings and macros share a common string table,
defining a string
.Ar name
clobbers the macro
.Ar name ,
and the
.Ar name
used for defining a string can also be invoked as a macro,
in which case the following input line will be appended to the
.Ar string ,
forming a new input line passed to the
.Nm
parser.
For example,
.Bd -literal -offset indent
\&.ds badidea .S
\&.badidea
H SYNOPSIS
.Ed
.Pp
invokes the
.Cm SH
macro when used in a
.Xr man 7
document.
Such abuse is of course strongly discouraged.
.Ss \&el
The
.Qq else
half of an if/else conditional.
Pops a result off the stack of conditional evaluations pushed by
.Sx \&ie
and uses it as its conditional.
If no stack entries are present (e.g., due to no prior
.Sx \&ie
calls)
then false is assumed.
The syntax of this request is similar to
.Sx \&if
except that the conditional is missing.
.Ss \&hy
Set automatic hyphenation mode.
This line-scoped request is currently ignored.
.Ss \&ie
The
.Qq if
half of an if/else conditional.
The result of the conditional is pushed into a stack used by subsequent
invocations of
.Sx \&el ,
which may be separated by any intervening input (or not exist at all).
Its syntax is equivalent to
.Sx \&if .
.Ss \&if
Begins a conditional.
Right now, the conditional evaluates to true
if and only if it starts with the letter
.Sy n ,
indicating processing in nroff style as opposed to troff style.
If a conditional is false, its children are not processed, but are
syntactically interpreted to preserve the integrity of the input
document.
Thus,
.Pp
.D1 \&.if t .ig
.Pp
will discard the
.Sq \&.ig ,
which may lead to interesting results, but
.Pp
.D1 \&.if t .if t \e{\e
.Pp
will continue to syntactically interpret to the block close of the final
conditional.
Sub-conditionals, in this case, obviously inherit the truth value of
the parent.
This request has the following syntax:
.Bd -literal -offset indent
\&.if COND \e{\e
BODY...
\&.\e}
.Ed
.Bd -literal -offset indent
\&.if COND \e{ BODY
BODY... \e}
.Ed
.Bd -literal -offset indent
\&.if COND \e{ BODY
BODY...
\&.\e}
.Ed
.Bd -literal -offset indent
\&.if COND \e
BODY
.Ed
.Pp
COND is a conditional statement.
roff allows for complicated conditionals; mandoc is much simpler.
At this time, mandoc supports only
.Sq n ,
evaluating to true;
and
.Sq t ,
.Sq e ,
and
.Sq o ,
evaluating to false.
All other invocations are read up to the next end of line or space and
evaluate as false.
.Pp
If the BODY section is begun by an escaped brace
.Sq \e{ ,
scope continues until a closing-brace escape sequence
.Sq \.\e} .
If the BODY is not enclosed in braces, scope continues until
the end of the line.
If the COND is followed by a BODY on the same line, whether after a
brace or not, then requests and macros
.Em must
begin with a control character.
It is generally more intuitive, in this case, to write
.Bd -literal -offset indent
\&.if COND \e{\e
\&.foo
bar
\&.\e}
.Ed
.Pp
than having the request or macro follow as
.Pp
.D1 \&.if COND \e{ .foo
.Pp
The scope of a conditional is always parsed, but only executed if the
conditional evaluates to true.
.Pp
Note that text following an
.Sq \&.\e}
escape sequence is discarded.
Furthermore, if an explicit closing sequence
.Sq \e}
is specified in a free-form line, the entire line is accepted within the
scope of the prior request, not only the text preceding the close, with the
.Sq \e}
collapsing into a zero-width space.
.Ss \&ig
Ignore input.
Its syntax can be either
.Bd -literal -offset indent
.Pf . Cm \&ig
.Ar ignored text
\&..
.Ed
.Pp
or
.Bd -literal -offset indent
.Pf . Cm \&ig Ar end
.Ar ignored text
.Pf . Ar end
.Ed
.Pp
In the first case, input is ignored until a
.Sq \&..
request is encountered on its own line.
In the second case, input is ignored until the specified
.Sq Pf . Ar end
macro is encountered.
Do not use the escape character
.Sq \e
anywhere in the definition of
.Ar end ;
it would cause very strange behaviour.
.Pp
When the
.Ar end
macro is a roff request or a roff macro, like in
.Pp
.D1 \&.ig if
.Pp
the subsequent invocation of
.Sx \&if
will first terminate the
.Ar ignored text ,
then be invoked as usual.
Otherwise, it only terminates the
.Ar ignored text ,
and arguments following it or the
.Sq \&..
request are discarded.
.Ss \&ne
Declare the need for the specified minimum vertical space
before the next trap or the bottom of the page.
This line-scoped request is currently ignored.
.Ss \&nh
Turn off automatic hyphenation mode.
This line-scoped request is currently ignored.
.Ss \&rm
Remove a request, macro or string.
This request is intended to have one argument,
the name of the request, macro or string to be undefined.
Currently, it is ignored including its arguments,
and the number of arguments is not checked.
.Ss \&nr
Define a register.
A register is an arbitrary string value that defines some sort of state,
which influences parsing and/or formatting.
Its syntax is as follows:
.Pp
.D1 Pf \. Cm \&nr Ar name Ar value
.Pp
The
.Ar value
may, at the moment, only be an integer.
So far, only the following register
.Ar name
is recognised:
.Bl -tag -width Ds
.It Cm nS
If set to a positive integer value, certain
.Xr mdoc 7
macros will behave in the same way as in the
.Em SYNOPSIS
section.
If set to 0, these macros will behave in the same way as outside the
.Em SYNOPSIS
section, even when called within the
.Em SYNOPSIS
section itself.
Note that starting a new
.Xr mdoc 7
section with the
.Cm \&Sh
macro will reset this register.
.El
.Ss \&so
Include a source file.
Its syntax is as follows:
.Pp
.D1 Pf \. Cm \&so Ar file
.Pp
The
.Ar file
will be read and its contents processed as input in place of the
.Sq \&.so
request line.
To avoid inadvertant inclusion of unrelated files,
.Xr mandoc 1
only accepts relative paths not containing the strings
.Qq ../
and
.Qq /.. .
.Ss \&tr
Output character translation.
This request is intended to have one argument,
consisting of an even number of characters.
Currently, it is ignored including its arguments,
and the number of arguments is not checked.
.Ss \&T&
Re-start a table layout, retaining the options of the prior table
invocation.
See
.Sx \&TS .
.Ss \&TE
End a table context.
See
.Sx \&TS .
.Ss \&TS
Begin a table, which formats input in aligned rows and columns.
A table consists of an optional single line of table options terminated
by a semicolon, followed by one or more lines of layout specification
terminated by a period, then table data.
A table block may also include
.Nm ,
.Xr mdoc 7 ,
or
.Xr man 7
macros.
Example:
.Bd -literal -offset indent
\&.TS
box tab(:);   \e" Table-wide options.
c | c         \e" Layout for first line.
| c | c.      \e" Layout for all subsequent lines.
1:2           \e" Data...
3:4
\&.TE
.Ed
.Pp
Table data is
.Em pre-processed ,
that is, data rows are parsed then inserted into the underlying stream
of input data.
This allows data rows to be interspersed by arbitrary macros, such as
.Bd -literal -offset indent
\&.TS
tab(:);
c c c.
1:2:3
\&.Ao
3:2:1
\&.Ac
\&.TE
.Ed
.Pp
in the case of
.Xr mdoc 7
or
.Bd -literal -offset indent
\&.TS
tab(:);
c c c.
\&.ds ab 2
1:\e*(ab:3
\&.I
3:2:1
\&.TE
.Ed
.Pp
in the case of
.Xr man 7 .
.Pp
The first line of a table consists of its options, which consists of
space-separated keys and modifiers terminated by a semicolon.
If the first line does not have a terminating semicolon, it is assumed
that no options are specified and instead a layout is processed.
Some options accept arguments enclosed by paranthesis.
The following case-insensitive options are available:
.Bl -tag -width Ds
.It Cm center
This option is not supported by
.Xr mandoc 1 .
This may also be invoked with
.Cm centre .
.It Cm delim
Accepts a two-character argument.
This option is not supported by
.Xr mandoc 1 .
.It Cm expand
This option is not supported by
.Xr mandoc 1 .
.It Cm box
Draw a single-line box around the table.
This may also be invoked with
.Cm frame .
.It Cm doublebox
Draw a double-line box around the table.
This may also be invoked with
.Cm doubleframe .
.It Cm allbox
This option is not supported by
.Xr mandoc 1 .
.It Cm tab
Accepts a single-character argument.
This character is used a delimiter between data cells, which otherwise
defaults to the tab character.
.It Cm linesize
Accepts a natural number (all digits).
This option is not supported by
.Xr mandoc 1 .
.It Cm nokeep
This option is not supported by
.Xr mandoc 1 .
.It Cm decimalpoint
Accepts a single-character argument.
This character will be used as the decimal point with the
.Cm n
layout key.
This option is not supported by
.Xr mandoc 1 .
.It Cm nospaces
This option is not supported by
.Xr mandoc 1 .
.El
.Pp
The table layout follows table options, except in the case of
.Sx \&T& ,
where it immediately procedes invocation.
Layout specifies how data rows are displayed on output.
Each layout line corresponds to a line of data; the last layout line
applies to all remaining data lines.
Layout lines may also be separated by a comma.
Each layout cell consists of one of the following case-insensitive keys:
.Bl -tag -width Ds
.It Cm c
Centre a literal string within its column.
.It Cm r
Right-justify a literal string within its column.
.It Cm l
Left-justify a literal string within its column.
.It Cm n
Justify a number around its decimal point.
If the decimal point is not found on the number, it's assumed to trail
the number.
.It Cm s
This option is not supported by
.Xr mandoc 1 .
.It Cm a
This option is not supported by
.Xr mandoc 1 .
.It Cm ^
This option is not supported by
.Xr mandoc 1 .
.It Cm \-
Replace the data cell (its contents will be lost) with a single
horizontal line.
This may also be invoked with
.Cm _ .
.It Cm =
Replace the data cell (its contents will be lost) with a double
horizontal line.
.It Cm \(ba
Emit a vertical bar instead of data.
.It Cm \(ba\(ba
Emit a double-vertical bar instead of data.
.El
.Pp
For example, following layout specifies a centre-justified column of
minimum width 10, followed by vertical bar, followed by a left-justified
column of minimum width 10, another vertical bar, then a column
justified about the decimal point in numbers:
.Pp
.Dl c10 | l10 | n
.Pp
Keys may be followed by a set of modifiers.
A modifier is either a modifier key or a natural number for specifying
spacing.
The following case-insensitive modifier keys are available:
.Cm z ,
.Cm u ,
.Cm e ,
.Cm t ,
.Cm d ,
.Cm f ,
.Cm b ,
.Cm i ,
.Cm b ,
and
.Cm i .
All of these are ignored by
.Xr mandoc 1 .
.Pp
The data section follows the last layout row.
By default, cells in a data section are delimited by a tab.
This behaviour may be changed with the
.Cm tab
option.
If
.Cm _
or
.Cm =
is specified, a single or double line, respectively, is drawn across the
data field.
If
.Cm \e-
or
.Cm \e=
is specified, a line is drawn within the data field (i.e., terminating
within the cell and not draw to the border).
.Sh COMPATIBILITY
This section documents compatibility between mandoc and other other
.Nm
implementations, at this time limited to GNU troff
.Pq Qq groff .
The term
.Qq historic groff
refers to groff version 1.15.
.Pp
.Bl -dash -compact
.It
The
.Cm nS
register is only compatible with OpenBSD's groff-1.15.
.It
Historic groff did not accept white-space before a custom
.Ar end
macro for the
.Sx \&ig
request.
.It
The
.Sx \&if
and family would print funny white-spaces with historic groff when
using the next-line syntax.
.El
.Sh SEE ALSO
.Xr mandoc 1 ,
.Xr man 7 ,
.Xr mandoc_char 7 ,
.Xr mdoc 7
.Rs
.%A M. E. Lesk
.%T Tbl\(emA Program to Format Tables
.%D June 11, 1976
.%U http://www.kohala.com/start/troff/v7/man/tbl/tbl.ps
.Re
.Rs
.%A Joseph F. Ossanna
.%A Brian W. Kernighan
.%I AT&T Bell Laboratories
.%T Troff User's Manual
.%R Computing Science Technical Report
.%N 54
.%C Murray Hill, New Jersey
.%D 1976 and 1992
.%U http://www.kohala.com/start/troff/cstr54.ps
.Re
.Rs
.%A Joseph F. Ossanna
.%A Brian W. Kernighan
.%A Gunnar Ritter
.%T Heirloom Documentation Tools Nroff/Troff User's Manual
.%D September 17, 2007
.%U http://heirloom.sourceforge.net/doctools/troff.pdf
.Re
.Sh HISTORY
The RUNOFF typesetting system was written in PL/1 for the CTSS
operating system by Jerome ("Jerry") E. Saltzer in 1961.
It was first used as the main documentation tool by Multics since 1963.
Robert ("Bob") H. Morris ported it to the GE-635 and called it
.Nm ,
Doug McIlroy rewrote it in BCPL in 1969,
Joseph F. Ossanna rewrote it in PDP-11 assembly in 1973,
and Brian W. Kernighan rewrote it in C in 1975.
.Sh AUTHORS
.An -nosplit
This partial
.Nm
reference was written by
.An Kristaps Dzonsons Aq kristaps@bsd.lv
and
.An Ingo Schwarze Aq schwarze@openbsd.org .