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GROFF_TMAC(5)                 File Formats Manual                GROFF_TMAC(5)



NAME
       groff_tmac - macro files in the roff typesetting system

DESCRIPTION
       The  roff(7) type-setting system provides a set of macro packages suit-
       able 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  usu-
       ally  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 stan-
              dard for man pages; see groff_mdoc(7).

   Full Packages
       The packages in this section provide a complete set of macros for writ-
       ing  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 -m; when this option was  directly  fol-
       lowed  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 documenta-
       tion, 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 speci-
       fied 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 ac-
       cording  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  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_name(7), with a leading `m' for the classical packages.

INCLUSION
       There are several ways to use a macro package in a document.  The clas-
       sical way is to specify the troff/groff option  -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  pre-
       processor  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 document
       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  for-
       matting constructs, such as requests, escape sequences, strings, numer-
       ic registers, and macros from a macro package.  These elements are  de-
       scribed 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  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 protect-
       ed  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 infor-
       mation on the arguments that were passed to the macro to the  terminal,
       define 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 position-
       al 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 escape  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 enclosing the macro definition(s)
       into a pair of .eo and .ec requests.  Then the body in the macro  defi-
       nition  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  ad-
       vanced  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
       o 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]
         ..

       o 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.

       o In  long  macro definitions, make ample use of comment lines or empty
         lines for a better structuring.

       o To increase readability, use groff's  indentation  facility  for  re-
         quests and macro calls (arbitrary whitespace after the leading dot).

   Diversions
       Diversions  can  be  used  to  realize  quite advanced programming con-
       structs.  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 di-
       version 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 every-
       thing  between each call of this macro pair is stored within the diver-
       sion and can be manipulated from within the macros.

FILES
       All macro names must be named name.tmac to fully use  the  tmac  mecha-
       nism.   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):

       o the directories specified with troff/groff's -M command line option

       o the directories given in the $GROFF_TMAC_PATH environment variable

       o the  current  directory  (only if in unsafe mode, which is enabled by
         the -U command line switch)

       o the home directory

       o a platform-specific directory, being /usr/lib/groff/site-tmac in this
         installation

       o a     site-specific     (platform-independent)    directory,    being
         /usr/share/groff/site-tmac in this installation

       o 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 previous section for  a  de-
              tailed description.

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

       This document is distributed under the terms of the FDL (GNU Free Docu-
       mentation 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 GNU
       copyleft site <http://www.gnu.org/copyleft/fdl.html>;.

       This document is part of groff, the  GNU  roff  distribution.   It  was
       written  by  Bernd Warken <bwarkenATmayn.de>; it is maintained by Werner
       Lemberg <wlATgnu.org>.

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.

       The Filesystem Hierarchy Standard is available at the FHS web site
       <http://www.pathname.com/fhs/>;.



Groff Version 1.18.1               Nov  2002                     GROFF_TMAC(5)