The ruleset associated with a given name
See rulesets for an introduction to rulesets.
Examples of calls of ruleset:
(ruleset 'my-ruleset) ; assumes that WORLD is bound
(ruleset 'my-ruleset (w state)) ; ruleset currently associated with MY-RULESET
Also see get-ruleset. For a more powerful operator that recursively
expands ruleset names within a given ruleset, see expand-ruleset.