Rule

A rule specifies a set of procedural expressions that query model elements to :

• create new model elements,
• update attributes and references of model elements,
• launch text generations using text templates.

A rule can query elements either in source and target models, and can create/update elements in source and target models as well. A rule is an atomic element of model transformation. A rule may call other rules to perform a complex task. Rules are grouped into logical units, called rulesets.

A rule may point to a parent rule, in which case it means :

• The child rule has direct access to the parameters of its parent rule (including recursive parent rules).
• The child rule can only be called:
  • from its parent rule.
  • from its parent rule direct subrules (i.e. sister rules).

Using subrules may help to organize a ruleset into logical rule trees. The main point is to share parameters: subrules don't have to redefine parent rules parameters.

Ruleset structure
Rule statement