The main control structure of a generator loop is the foreach loop. In a typical generator the foreach clause selects all elements of the specified type to be operated on. A foreach loop can only be used when the element stack contains a graph, most often as the outermost loop at the top level of a generator. The element type to be looped over cannot be a property or port: only objects, roles and relationships are appropriate. The operations that will be performed on the retrieved elements are written within the curly brackets, {}.

foreach .objType
{ /* Operations for the elements */ }