path: root/doc/grecs_config.5
diff options
Diffstat (limited to 'doc/grecs_config.5')
1 files changed, 343 insertions, 0 deletions
diff --git a/doc/grecs_config.5 b/doc/grecs_config.5
new file mode 100644
index 0000000..579875b
--- /dev/null
+++ b/doc/grecs_config.5
@@ -0,0 +1,343 @@
+.\" This file is part of grecs -*- nroff -*-
+.\" Copyright (C) 2007, 2009-2011 Sergey Poznyakoff
+.\" Grecs is free software; you can redistribute it and/or modify
+.\" it under the terms of the GNU General Public License as published by
+.\" the Free Software Foundation; either version 3, or (at your option)
+.\" any later version.
+.\" Grecs is distributed in the hope that it will be useful,
+.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
+.\" GNU General Public License for more details.
+.\" You should have received a copy of the GNU General Public License
+.\" along with Grecs. If not, see <http://www.gnu.org/licenses/>.
+.\" This file is part of SLB.
+.\" Copyright (C) 2011 Sergey Poznyakoff
+.TH GRECS_CONFIG 3 "May 4, 2011" "GRECS" "Grecs User Reference"
+\fBGrecs\fR configuration file syntax
+A configuration file consists of statements and comments.
+There are three classes of lexical tokens: keywords, values, and
+separators. Blanks, tabs, newlines and comments, collectively called
+\fIwhite space\fR are ignored except as they serve to separate
+tokens. Some white space is required to separate otherwise adjacent
+keywords and values.
+Comments may appear anywhere where white space may appear in the
+configuration file. There are two kinds of comments:
+single-line and multi-line comments. Single-line comments start
+.B #
+.B //
+and continue to the end of the line:
+.RS 4
+# This is a comment
+// This too is a comment
+\fIMulti-line\fB or \fIC-style\fB comments start with the two
+.B /*
+(slash, star) and continue until the first occurrence of
+.B */
+(star, slash).
+Multi-line comments cannot be nested. However, single-line comments
+may well appear within multi-line ones.
+.SS "Pragmatic Comments"
+Pragmatic comments are similar to usual single-line comments,
+except that they cause some changes in the way the configuration is
+parsed. Pragmatic comments begin with a
+.B #
+sign and end with the next physical newline character.
+.BR "#include <" "file" >
+.PD 0
+.BR "#include " "file"
+Include the contents of the file \fIfile\fR. If it is an
+absolute file name, both forms are equivalent. Otherwise, the form
+with angle brackets searches for the file in the \fIinclude
+search path\fR, while the second one looks for it in the current working
+directory first, and, if not found there, in the include search
+The default include search path is:
+where \fIprefix\fR stands for the installation prefix (normally
+\fB/usr\fR or \fB/usr/local\fR), \fIPROGNAME\fR stands for the name of
+the program which uses the configuration file, and \fIVERSION\fR for
+its version number.
+The include search path can be modified using the
+.BI grecs_include_path_setup ()
+.BI grecs_include_path_setup_v ()
+functions. Refer to
+.BR grecs_include_path_setup (3),
+for a detailed discussion.
+.BR "#include_once <" "file" >
+.PD 0
+.BR "#include_once " "file"
+Same as \fB#include\fR, except that, if the \fIfile\fR has already
+been included, it will not be included again.
+.BR "#line " "num"
+.PD 0
+.BR "#line " "num" " \(dq" "file" "\(dq"
+This line causes the parser to believe, for purposes of error
+diagnostics, that the line number of the next source line
+is given by \fInum\fR and the current input file is named by
+\fIfile\fR. If the latter is absent, the remembered file name
+does not change.
+.BR "# " "num" " \(dq" "file" "\(dq"
+This is a special form of the \fB#line\fR statement, understood for
+compatibility with the C preprocessor.
+These statements provide a rudimentary preprocessing
+features. For more sophisticated ways to modify configuration before
+parsing, see \fBPREPROCESSOR\fR.
+.SS "Simple statement"
+A \fIsimple statement\fR consists of a keyword and value
+separated by any amount of whitespace. Simple statement is terminated
+with a semicolon (\fB;\fR).
+The following is a simple statement:
+.RS 4
+standalone yes;
+pidfile /var/run/slb.pid;
+A \fIkeyword\fR begins with a letter and may contain letters,
+decimal digits, underscores (\fB_\fR) and dashes (\fB-\fR).
+Examples of keywords are:
+.RS 4
+A \fIvalue\fR can be one of the following:
+.I number
+A number is a sequence of decimal digits.
+.I boolean
+A boolean value is one of the following: \fByes\fR, \fBtrue\fR,
+\fBt\fR or \fB1\fR, meaning \fItrue\fR, and \fBno\fR,
+\fBfalse\fR, \fBnil\fR, \fB0\fR meaning \fIfalse\fR.
+.I unquoted string
+An unquoted string may contain letters, digits, and any of the
+following characters: \fB_\fR, \fB\-\fR, \fB.\fR, \fB/\fR,
+\fB@\fR, \fB*\fR, \fB:\fR.
+.I quoted string
+A quoted string is any sequence of characters enclosed in
+double-quotes (\fB\(dq\fR). A backslash appearing within a quoted
+string introduces an \fIescape sequence\fR, which is replaced
+with a single character according to the following rules:
+ Sequence Replaced with
+ \\a Audible bell character (ASCII 7)
+ \\b Backspace character (ASCII 8)
+ \\f Form-feed character (ASCII 12)
+ \\n Newline character (ASCII 10)
+ \\r Carriage return character (ASCII 13)
+ \\t Horizontal tabulation character (ASCII 9)
+ \\v Vertical tabulation character (ASCII 11)
+ \\\\ A single backslash
+ \\\(dq A double-quote.
+In addition, the sequence \fB\\\fInewline\fR is removed from
+the string. This allows to split long strings over several
+physical lines, e.g.:
+ "a long string may be\\
+ split over several lines"
+If the character following a backslash is not one of those specified
+above, the backslash is ignored and a warning is issued.
+Two or more adjacent quoted strings are concatenated, which gives
+another way to split long strings over several lines to improve
+readability. The following fragment produces the same result as the
+example above:
+ "a long string may be"
+ " split over several lines"
+.I Here-document
+A \fIhere-document\fR is a special construct that allows to introduce
+strings of text containing embedded newlines.
+.BI "<<" "word"
+construct instructs the parser to read all the following lines up to
+the line containing only \fIword\fR, with possible trailing blanks.
+Any lines thus read are concatenated together into a single string.
+For example:
+ <<EOT
+ A multiline
+ string
+The body of a here-document is interpreted the same way as a
+double-quoted string, unless \fIword\fR is preceded by a backslash
+(e.g. \fB<<\\EOT\fR) or enclosed in double-quotes, in which case
+the text is read as is, without interpretation of escape sequences.
+If \fIword\fR is prefixed with \fB\-\fR (a dash), then all leading
+tab characters are stripped from input lines and the line containing
+\fIword\fR. Furthermore, \fB\-\fR is followed by a single space,
+all leading whitespace is stripped from them. This allows to indent
+here-documents in a natural fashion. For example:
+ <<- TEXT
+ The leading whitespace will be
+ ignored when reading these lines.
+It is important that the terminating delimiter be the only token on
+its line. The only exception to this rule is allowed if a
+here-document appears as the last element of a statement. In this
+case a semicolon can be placed on the same line with its terminating
+delimiter, as in:
+ help-text <<-EOT
+ A sample help text.
+ EOT;
+.I list
+A comma-separated list of values, enclosed in parentheses. The
+following example shows a statement whose value is a list of strings:
+ alias (test, null);
+In any context where a list is appropriate, a single value is allowed
+without being a member of a list: it is equivalent to a list with a
+single member. This means that, e.g.
+ alias test;
+is equivalent to
+ alias (test);
+provided that the \fBalias\fR statement is defined as taking a list as
+its argument.
+.I block statement
+A block statement introduces a logical group of
+statements. It consists of a keyword, followed by an optional value,
+called a \fBtag\fR, and a sequence of statements enclosed in curly
+braces, as shown in the example below:
+ server srv1 {
+ host;
+ community "foo";
+ }
+The closing curly brace may be followed by a semicolon, although
+this is not required.
+Before being parsed, the configuration file is preprocessed.
+The built-in preprocessor handles only file inclusion
+.B #line
+statements, while the rest of traditional preprocessing facilities,
+such as macro expansion, is supported via
+.BR m4 (1),
+which is used as external preprocessor.
+The external preprocessor is invoked with the \fB-s\fR flag, which
+instructs it to include line synchronization information in its
+output. This information is then used by the parser to display meaningful
+An initial set of macro definitions is supplied in the file named
+\fBpp-setup\fR file, which is located in
+The default \fBpp-setup\fR file renames all m4 built-in
+macro names so they all start with the prefix \fBm4_\fI. This
+is similar to GNU m4 \fB--prefix-builtin\fR option, but has an
+advantage that it works with non-GNU m4 implementations as
+.BR m4 (1),
+.BR grecs_parse (3),
+.BR grecs_include_path_setup (3),
+.BR grecs_tree_process (3).
+Sergey Poznyakoff
+Report bugs to <gray+grecs@gnu.org.ua>.
+The \fBGrecs\fR library is constantly changing, so this manual page
+may be incorrect or out-of-date. For the latest copy of \fBGrecs\fR
+documentation, visit <http://www.gnu.org.ua/software/grecs>.
+Copyright \(co 2011 Sergey Poznyakoff
+License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.
+.\" Local variables:
+.\" eval: (add-hook 'write-file-hooks 'time-stamp)
+.\" time-stamp-start: ".TH [A-Z_][A-Z0-9_]* [0-9] \""
+.\" time-stamp-format: "%:B %:d, %:y"
+.\" time-stamp-end: "\""
+.\" time-stamp-line-limit: 20
+.\" end:

Return to:

Send suggestions and report system problems to the System administrator.