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diff --git a/doc/rainerscript.html b/doc/rainerscript.html new file mode 100644 index 00000000..ef0e41cb --- /dev/null +++ b/doc/rainerscript.html @@ -0,0 +1,63 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html><head> +<meta http-equiv="Content-Language" content="en"><title>RainerScript</title> + +</head> +<body> +<h1>RainerScript</h1> +<p><b>RainerScript is a scripting language specifically +designed and well-suited +for processing network events and configuring event processors</b> +(with the most prominent sample being syslog). While RainerScript is +theoritically usable with various softwares, it currently is being +used, and developed for, rsyslog. Please note that RainerScript may not +be abreviated as rscript, because that's somebody elses trademark.</p> +<p>RainerScript is currently under development. It has its first +appearance in rsyslog 3.12.0, where it provides complex expression +support. However, this is only a very partial implementatio of the +scripting language. Due to technical restrictions, the final +implementation will have a slightly different syntax. So while you are +invited to use the full power of expresssions, you unfortunatley need +to be prepared to change your configuration files at some later points. +Maintaining backwards-compatibility at this point would cause us to +make too much compromise. Defering the release until everything is +perfect is also not a good option. So use your own judgement.</p> +<p>A formal definition of the language can be found in <a href="rscript_abnf.html">RainerScript ABNF</a>. The +rest of this document describes the language from the user's point of +view. Please note that this doc is also currently under development and +can (and will) probably improve as time progresses. If you have +questions, use the rsyslog forum. Feedback is also always welcome.</p> +<h2>Data Types</h2> +RainerScript is a typeless language. That doesn't imply you don't need +to care about types. Of course, expressions like "A" + "B" will not +return a valid result, as you can't really add two letters (to +concatenate them, use the concatenation operator &). + However, all type conversions are automatically done by the +script interpreter when there is need to do so.<br> +<h2>Expressions</h2> +The language supports arbitrary complex expressions. All usual +operators are supported. The precedence of operations is as follows +(with operations being higher in the list being carried out before +those lower in the list, e.g. multiplications are done before additions.<br> +<ul> +<li>expressions in parenthesis</li><li>not, unary minus</li><li>*, /, % (modulus, as in C)</li><li>+, -, & (string concatenation)</li><li>==, !=, <>, <, >, <=, >=, contains (strings!), startswith (strings!)</li><li>and</li><li>or</li> +</ul>For example, "not a == b" probably returns not what you intended. +The script processor will first evaluate "not a" and then compare the +resulting boolean to the value of b. What you probably intended to do +is "not (a == b)". And if you just want to test for inequality, we +highly suggest to use "!=" or "<>". Both are exactly the same and +are provided so that you can pick whichever you like best. So inquality +of a and b should be tested as "a <> b". The "not" operator +should be reserved to cases where it actually is needed to form a +complex boolean expression. In those cases, parenthesis are highly +recommended. +<p>[<a href="rsyslog_conf.html">rsyslog.conf overview</a>] +[<a href="manual.html">manual index</a>] [<a href="http://www.rsyslog.com/">rsyslog site</a>]</p> +<p><font size="2">This documentation is part of the +<a href="http://www.rsyslog.com/">rsyslog</a> +project.<br> +Copyright © 2008 by <a href="http://www.gerhards.net/rainer">Rainer +Gerhards</a> and +<a href="http://www.adiscon.com/">Adiscon</a>. +Released under the GNU GPL version 3 or higher.</font></p> +</body></html>
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