NAME

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
‘T roffMAC ros’.     

    

The tmac files are normal roff source documents, except that they
usually contain only definitions and setup commands, 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 functionality 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
when this option was directly followed by its argument without an
intervening space, this looked like a long option preceded by a single
minus [em] 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
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
or
for short.
    

    

For similar reasons, macro packages that did not start with an
had a leading
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
    

    

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
the other one without it.
So in
groff, the
man macro package may be specified as on of the following four methods:



























Recent packages that do not start with
do not use an additional
in the documentation.
For example, the
www macro package may be specified only as one of the two methods:


















Obviously, variants like
-mmwww would not make much sense.
    

    

A second strange feature of classical troff was to name macro files
according to
\$@ 
In modern operating systems, the type of a file is specified as
postfix, the file name extension.
Again, groff copes with this situation 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_
I]name
](7),
with a leading
for the classical packages.


    

    
INCLUSION

    

    

There are several ways to use a macro package in a document.
The classical way is to specify the troff/groff option
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
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
package, which added searching in the tmac path, just like option
does.
    

    

Note that in order to resolve the
and
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
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 document called
docu.roff.     

    

At run-time, the formatter call for this is


















To include the macro file directly in the document either














is used or














In both cases, the formatter is called with















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
request or the option

































































    

    
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, Ellipsis],
$9, $[Ellipsis]], $*, and
$@, the name under which the macro was called is in
$0, and the number of arguments is in register
0.$]; 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~preprocessing 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 interpreted 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 doubling the backslash that introduces the
escape sequence.
This doubling is most important for the positional parameters.
For example, to print information on the arguments that were passed to
the macro to the terminal, define a macro named ‘.print_args’,
say.
    

    


    




    

    

When calling this macro by
    

    


    




    

    

the following text is printed to the terminal:

    


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

[rs][rs]$* and
[rs][rs][.$]. The same applies to the macro name because it could be called with an
alias name, so
[rs][rs]$0.     

    

On the other hand,
midpart is a constant string, it will not change, so no doubling for
[rs]*[midpart]. The
[rs]f escape sequences are predefined groff elements for setting the font
within the text.
Of course, this behavior will not change, so no doubling with
[rs]f[I] and
[rs]f[].     


Draft Mode

    

Writing groff macros is easy when the escaping mechanism is temporarily
disabled.
In groff, this is done by enclosing 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 [em] text enhanced by calls of requests, macros,
strings, registers, etc.
For example, the code above can be written in a simpler way by
    

    


    




    

    

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.
















 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:
















 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 dynamically 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 results 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 applied 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
 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

    

    





 A colon separated list of additional tmac directories in which to search



 for macro files.
See the previous section for a detailed description.





    

    
AUTHOR

    

    

Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
    

    

This document is distributed under the terms of the FDL (GNU Free
Documentation License) version 1.1 or later.
You should have received a copy of the FDL on your system, it is also
available on-line at the
    

    

This document is part of
groff, the GNU roff distribution.
It was written by
it is maintained by
    

    
SEE ALSO

    

    

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.






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