Provided by: groff_1.18.1.1-16_i386 bug

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 ‘TroffMACros’.

       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  -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  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
       classical 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
       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 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
       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  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.

              .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 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
       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 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 $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 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
       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 〈bwarken@mayn.de〉; it is maintained  by  Werner
       Lemberg 〈wl@gnu.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/〉.