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groff_tmac - macro files in the roff typesetting system
DESCRIPTION
The roff(7) type-setting system provides a set of macro packages suitable for special kinds of documents. Each
macro package stores its macros and definitions in a file called the package's tmac file. The name is deduced
from `TroffMACros'.
The tmac files are normal roff source documents, except that they usually contain only definitions and setup com-
mands, but no text. All tmac files are kept in a single or a small number of directories, the tmac directories.
GROFF MACRO PACKAGES
groff provides all classical macro packages, some more full packages, and some secondary packages for special
purposes.
Man Pages
man This is the classical macro package for UNIX manual pages (man pages); it is quite handy and easy to use;
see groff_man(7).
doc
mdoc An alternative macro package for man pages mainly used in BSD systems; it provides many new features, but
it is not the standard for man pages; see groff_mdoc(7).
Full Packages
The packages in this section provide a complete set of macros for writing documents of any kind, up to whole
books. They are similar in functionality; it is a matter of taste which one to use.
me The classical me macro package; see groff_me(7).
mm The semi-classical mm macro package; see groff_mm(7).
mom The new mom macro package, only available in groff. As this is not based on other packages, it can be
freely designed. So it is expected to become quite a nice, modern macro package. See groff_mom(7).
ms The classical ms macro package; see groff_ms(7).
Special Packages
The macro packages in this section are not intended for stand-alone usage, but can be used to add special func-
tionality to any other macro package or to plain groff.
tty-char
Overrides the definition of standard troff characters and some groff characters for tty devices. The
optical appearance is intentionally inferior compared to that of normal tty formatting to allow processing
with critical equipment.
www Additions of elements known from the html format, as being used in the internet (World Wide Web) pages;
this includes URL links and mail addresses; see groff_www(7).
NAMING
In classical roff systems, there was a funny naming scheme for macro packages, due to a simplistic design in
option parsing. Macro packages were always included by option -m; when this option was directly followed by its
argument without an intervening space, this looked like a long option preceded by a single minus -- a sensation
in the computer stone age. To make this optically working for macro package names, all classical macro packages
choose a name that started with the letter `m', which was omitted in the naming of the macro file.
For example, the macro package for the man pages was called man, while its macro file tmac.an. So it could be
activated by the argument an to option -m, or -man for short.
For similar reasons, macro packages that did not start with an `m' had a leading `m' added in the documentation
and in talking; for example, the package corresponding to tmac.doc was called mdoc in the documentation, although
a more suitable name would be doc. For, when omitting the space between the option and its argument, the command
line option for activating this package reads -mdoc.
To cope with all situations, actual versions of groff(1) are smart about both naming schemes by providing two
macro files for the inflicted macro packages; one with a leading `m', the other one without it. So in groff, the
man macro package may be specified as on of the following four methods:
sh# groff -m man
sh# groff -man
sh# groff -mman
sh# groff -m an
Recent packages that do not start with `m' do not use an additional `m' in the documentation. For example, the
www macro package may be specified only as one of the two methods:
sh# groff -m www
sh# groff -mwww
Obviously, variants like -mmwww would not make much sense.
A second strange feature of classical troff was to name macro files according to tmac.name. In modern operating
systems, the type of a file is specified as postfix, the file name extension. Again, groff copes with this situ-
ation by searching both anything.tmac and tmac.anything if only anything is specified.
The easiest way to find out which macro packages are available on a system is to check the man page groff(1), or
the contents of the tmac directories.
In groff, most macro packages are described in man pages called groff_name(7), with a leading `m' for the classi-
cal packages.
INCLUSION
There are several ways to use a macro package in a document. The classical way is to specify the troff/groff op-
tion -m name at run-time; this makes the contents of the macro package name available. In groff, the file
name.tmac is searched within the tmac path; if not found, tmac.name will be searched for instead.
Alternatively, it is also possible to include a macro file by adding the request .so filename into the document;
the argument must be the full file name of an existing file, possibly with the directory where it is kept. In
groff, this was improved by the similar request .mso package, which added searching in the tmac path, just like
option -m does.
Note that in order to resolve the .so and .mso requests, the roff preprocessor soelim(1) must be called if the
files to be included need preprocessing. This can be done either directly by a pipeline on the command line or
by using the troff/groff option -s. man calls soelim automatically.
For example, suppose a macro file is stored as /usr/share/groff/1.18.1/tmac/macros.tmac and is used in some docu-
ment called docu.roff.
At run-time, the formatter call for this is
sh# groff -m macrofile document.roff
To include the macro file directly in the document either
.mso macrofile.tmac
is used or
.so /usr/share/groff/1.18.1/tmac/macros.tmac
In both cases, the formatter is called with
sh# troff -s docu.roff
If you want to write your own groff macro file, call it whatever.tmac and put it in some directory of the tmac
path, see section FILES. Then documents can include it with the .mso request or the option -m.
WRITING MACROS
A roff(7) document is a text file that is enriched by predefined formatting constructs, such as requests, escape
sequences, strings, numeric registers, and macros from a macro package. These elements are described in roff(7).
To give a document a personal style, it is most useful to extend the existing elements by defining some macros
for repeating tasks; the best place for this is near the beginning of the document or in a separate file.
Macros without arguments are just like strings. But the full power of macros reveals when arguments are passed
with a macro call. Within the macro definition, the arguments are available as the escape sequences $1, ..., $9,
$[...], $*, and $@, the name under which the macro was called is in $0, and the number of arguments is in regis-
ter 0; see groff(7).
Copy-in Mode
The phase when groff reads a macro is called copy-in mode in roff-talk. This is comparable to the C preprocess-
ing phase during the development of a program written in the C language.
In this phase, groff interprets all backslashes; that means that all escape sequences in the macro body are in-
terpreted and replaced by their value. For constant expression, this is wanted, but strings and registers that
might change between calls of the macro must be protected from being evaluated. This is most easily done by dou-
bling the backslash that introduces the escape sequence. This doubling is most important for the positional pa-
rameters. For example, to print information on the arguments that were passed to the macro to the terminal, de-
fine a macro named `.print_args', say.
.ds midpart was called with
.de print_args
. tm \f[I]\\$0\f[] \\*[midpart] \\n[.$] arguments:
. tm \\$*
..
When calling this macro by
.print_args arg1 arg2
the following text is printed to the terminal:
print_args was called with the following 2 arguments:
arg1 arg2
Let's analyze each backslash in the macro definition. As the positional parameters and the number of arguments
will change with each call of the macro their leading backslash must be doubled, which results in \\$* and
\\[.$]. The same applies to the macro name because it could be called with an alias name, so \\$0.
On the other hand, midpart is a constant string, it will not change, so no doubling for \*[midpart]. The \f es-
cape sequences are predefined groff elements for setting the font within the text. Of course, this behavior will
not change, so no doubling with \f[I] and \f[].
Draft Mode
Writing groff macros is easy when the escaping mechanism is temporarily disabled. In groff, this is done by en-
closing the macro definition(s) into a pair of .eo and .ec requests. Then the body in the macro definition is
just like a normal part of the document -- text enhanced by calls of requests, macros, strings, registers, etc.
For example, the code above can be written in a simpler way by
.eo
.ds midpart was called with
.de print_args
. tm \f[I]\$0\f[] \*[midpart] \n[.$] arguments:
. tm \$*
..
.ec
Unfortunately, draft mode cannot be used universally. Although it is good enough for defining normal macros,
draft mode will fail with advanced applications, such as indirectly defined strings, registers, etc. An optimal
way is to define and test all macros in draft mode and then do the backslash doubling as a final step; do not
forget to remove the .eo request.
Tips for Macro Definitions
� Start every line with a dot, for example, by using the groff request .nop for text lines, or write your own
macro that handles also text lines with a leading dot.
.de Text
. if (\\n[.$] == 0) \
. return
. nop \)\\$*[rs]
..
� Write a comment macro that works both for copy-in and draft mode; for as escaping is off in draft mode, trouble
might occur when normal comments are used. For example, the following macro just ignores its arguments, so it
acts like a comment line:
.de c
..
.c This is like a comment line.
� In long macro definitions, make ample use of comment lines or empty lines for a better structuring.
� To increase readability, use groff's indentation facility for requests and macro calls (arbitrary whitespace
after the leading dot).
Diversions
Diversions can be used to realize quite advanced programming constructs. They are comparable to pointers to
large data structures in the C programming language, but their usage is quite different.
In their simplest form, diversions are multi-line strings, but they get their power when diversions are used dy-
namically within macros. The information stored in a diversion can be retrieved by calling the diversion just
like a macro.
Most of the problems arising with diversions can be avoided if you are conscious about the fact that diversions
always deal with complete lines. If diversions are used when the line buffer has not been flashed, strange re-
sults are produced; not knowing this, many people get desperate about diversions. To ensure that a diversion
works, line breaks should be added at the right places. To be on the secure side, enclose everything that has to
do with diversions into a pair of line breaks; for example, by amply using .br requests. This rule should be ap-
plied to diversion definition, both inside and outside, and to all calls of diversions. This is a bit of
overkill, but it works nicely.
[If you really need diversions which should ignore the current partial line, use environments to save the current
partial line and/or use the .box request.]
The most powerful feature using diversions is to start a diversion within a macro definition and end it within
another macro. Then everything between each call of this macro pair is stored within the diversion and can be
manipulated from within the macros.
FILES
All macro names must be named name.tmac to fully use the tmac mechanism. tmac.name as with classical packages
is possible as well, but deprecated.
The macro files are kept in the tmac directories; a colon separated list of these constitutes the tmac path.
The search sequence for macro files is (in that order):
� the directories specified with troff/groff's -M command line option
� the directories given in the $GROFF_TMAC_PATH environment variable
� the current directory (only if in unsafe mode, which is enabled by the -U command line switch)
� the home directory
� a platform-specific directory, being /usr/lib/groff/site-tmac in this installation
� a site-specific (platform-independent) directory, being /usr/share/groff/site-tmac in this installation
� the main tmac directory, being /usr/share/groff/1.18.1/tmac in this installation
ENVIRONMENT
$GROFF_TMAC_PATH
A colon separated list of additional tmac directories in which to search for macro files. See the previ-
ous section for a detailed description.
RELATED
A complete reference for all parts of the groff system is found in the groff info(1) file.
groff(1)
an overview of the groff system.
groff_man(7),
groff_mdoc(7),
groff_me(7),
groff_mm(7),
groff_mom(7),
groff_ms(7),
groff_www(7).
the groff tmac macro packages.
groff(7)
the groff language.
The Filesystem Hierarchy Standard is available at the FHS web site <http://www.pathname.com/fhs/>.
CATEGORY