1 Additional description for the shell version of `groffer'
6 The shell version of `groffer' contains two files, `groffer.sh' and
9 `groffer.sh' is a short introductory script without any functions. I
10 can be run with a very poor Bourne shell. It just contains some basic
11 variables, the reading of the configuration files, and the
12 determination of the shell for `groffer2.sh'. This script is
13 transformed by `make' into `groffer' which will be installed into
14 @bindir@, which is usually /usr/local/bin.
16 `groffer2.sh' is a long main script with all functions; it is called
17 by `groffer.sh' (`groffer' after installation). It is installed
18 unchanged into @libdir@/groff/groffer, which is usually
19 /usr/local/lib/groff/groffer. This script can be called with a
20 different shell, using the `groffer' option `--shell'.
25 The `groffer' shell scripts are compatible to both the GNU and the
26 POSIX shell and utilities. Care was taken to restrict the programming
27 technics used here in order to achieve POSIX compatibility as far back
28 as POSIX P1003.2 Draft 11.2 of September 1991. This draft is
29 available at http://www.funet.fi/pub/doc/posix/p1003.2/d11.2 in the
32 The POSIX draft does not include `local' variables for functions. So
33 this concept was replaced by global variables with a prefix that
34 differs for each function. The prefix is chosen from the function
35 name. These quasi-local variables are unset before each return of the
38 The `groffer' scripts were tested under the shells `ash', `bash',
39 `dash', 'ksh', `mksh', `pdksh', 'posh', and `zsh' without problems in
40 Linux Debian. A shell can be tested by the `groffer' option
41 `--shell', but that will run only with groffer2.sh. To start it
42 directly from the beginning under this shell the following command can
45 <shell-name> groffer.sh --shell=<shell-name> <argument>...
48 Some shells are not fully POSIX compatible. For them the following
49 restrictions were done. For more information look at the
50 documentation `Portable shells' in the `info' page of `autoconf'
51 (look-up in Emacs-Help-Manuals_Info).
53 - The command parts `then', `else', and `do' must be written each on a
56 - Replace `for i in "$@"' by `for i' and remove internal `;' (kah).
58 - Replace `set -- ...' by `set x ...; shift'. After the first
59 non-option argument, all arguments including those starting with `-'
60 are accepted as non-option. For variables or `$()' constructs with
61 line-breaks, use `eval set' without quotes. That transforms a
62 line-break within a variable to a space.
64 - The name of the variable in `for' is chosen as a single character
65 (old ash). The content of such variables is not safe because it can
66 also occur in other functions. So it is often stored in an
67 additional quasi-local variable.
69 - `echo' is not portable on options; some `echo' commands have many
70 options, others have none. So `echo -n' cannot be used, such that
71 the output of each function has complete lines. There are two
72 methods to avoid having `-' as the first character of any argument.
73 Either a character such as `x' can be prepended to the argument;
74 this must later on be removed by `sed'. Otherwise, `echo' can be
75 replaced by `cat <<EOF'.
77 - `ls' has problems. Old UNIX systems echoed the error message to
78 standard output. So handle the output with `sed'. If the output
79 contains `not found' map it to an empty string.
81 - As `test -e' is not available in Solaris 2.5 replace it by
84 - As `unset' is not supported by all shells replace it by `eval
85 ${_UNSET}' where this variable is `unset' if it exists and `:'
88 - Some shells have problems with options in `eval'. So quoting must
89 be done right to hide the options from `eval'.
91 - In backquote calls `` avoid the backquote ` in comments.
93 - Replace `true' by `:', `false' isn't used.
95 - Do not redefine builtins as functions (ash).
97 - Avoid `[^...]' in `case' patterns (ash).
99 - `trap' does not allow error code 127.
101 The scripts call the following commands with all options used:
132 test -c -d -f -r -s -w -x
140 The `groffer' script provides its own option parser. It is compatible
141 to the usual GNU style command line This includes long option names
142 with two signs such as `--option', clusters of short options, the
143 mixing of options and non-option file names, the option `--' to close
144 the option handling, and it is possible to abbreviate the long option
147 The flexible mixing of options and file names in GNU style is always
148 possible, even if the environment variable `$POSIXLY_CORRECT' is set
149 to a non-empty value. This disables the rather wicked POSIX behavior
150 to terminate option parsing when the first non-option command line
156 Error handling and exit behavior is complicated by the fact that
157 `exit' can only escape from the current shell; trouble occurs in
158 subshells. This was solved by sending kill signals, see $_PROCESS_ID
162 Function Definitions in `groffer2.sh'
164 Each funtion in groffer2.sh has a description that starts with the
165 function name and symbols for its arguments in paranthesis `()'. Each
166 `<>' construction gives an argument name that just gives a hint on
167 what the argument is meant to be; these argument names are otherwise
168 irrelevant. The `>' sign can be followed by another character that
169 shows how many of these arguments are possible.
171 <arg> exactly 1 of this argument
172 <arg>? 0 or 1 of these arguments
173 <arg>* arbitrarily many such arguments, incl. none
174 <arg>+ one or more such arguments
175 <arg>... one or more such arguments
176 [...] optional arguments
178 A function that starts with an underscore `_' is an internal function
179 for some other function. The internal functions are defined just
180 after their corresponding function.
183 External Environment Variables
185 The groffer.sh script uses the following external system variables.
186 It is supposed that these variables are already exported outside of
187 groffer.sh; otherwise they do not have a value within the script.
189 external system environment variables that are explicitly used
190 $DISPLAY: Presets the X display.
191 $LANG: For language specific man pages.
192 $LC_ALL: For language specific man pages.
193 $LC_MESSAGES: For language specific man pages.
194 $PAGER: Paging program for tty mode.
195 $PATH: Path for the programs called (`:' separated list).
197 groffer native environment variables
198 $GROFFER_OPT preset options for groffer.
200 all groff environment variables are used, see groff(1)
201 $GROFF_BIN_PATH: Path for all groff programs.
202 $GROFF_COMMAND_PREFIX: '' (normally) or 'g' (several troffs).
203 $GROFF_FONT_PATH: Path to non-default groff fonts.
204 $GROFF_TMAC_PATH: Path to non-default groff macro files.
205 $GROFF_TMPDIR: Directory for groff temporary files.
206 $GROFF_TYPESETTER: Preset default device.
208 all GNU man environment variables are used, see man(1).
209 $MANOPT: Preset options for man pages.
210 $MANPATH: Search path for man pages (: list).
211 $MANROFFSEQ: Ignored because of grog guessing.
212 $MANSECT: Search man pages only in sections (:).
213 $SYSTEM: Man pages for different OS's (, list).
216 Object-oriented Functions
218 The groffer script provides an object-oriented construction (OOP). In
219 object-oriented terminology, a type of object is called a `class'; a
220 function that handles objects from a class is named `method'.
222 In the groffer script, the object is a variable name whose content is
223 the object's data. Methods are functions that have an object as first
226 The basic functions for object handling are obj_*().
228 The class `list' represents an array structure, see list_*().
233 Last update: 2 August 2005
235 Copyright (C) 2003,2004,2005 Free Software Foundation, Inc.
236 Written by Bernd Warken
238 This file is part of `groffer', which is part of `groff'.
240 `groff' is free software; you can redistribute it and/or modify it
241 under the terms of the GNU General Public License as published by
242 the Free Software Foundation; either version 2, or (at your option)
245 `groff' is distributed in the hope that it will be useful, but WITHOUT
246 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
247 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
248 License for more details.
250 You should have received a copy of the GNU General Public License
251 along with `groff'; see the files COPYING and LICENSE in the top
252 directory of the `groff' source. If not, write to the Free Software
253 Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA.
256 ####### Emacs settings