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Line 1: A ruleset starts with the ruleset keyword, followed by the ruleset identifier or RID, and a curly brace. In this case, the RID is hello_world. The body of a ruleset is contained with in curly brackets.
Lines 2-10: A ruleset usually contains a meta block giving information about the ruleset. This information includes information like the ruleset name and author, as well as pragmas that affect the ruleset's behavior. For example, this ruleset has a shares pragma saying which global functions are shared with the outside world (including other rulesets).
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