Halliday & Matthiessen (1999: 148-9):
We have seen that figures of being, other than the existential, may be elaborative (intensive), extending (possessive) or enhancing (circumstantial). This enables us to recognisedfurther subcategories of doing according to the nature of the figure being brought about: see Table 4(7).
Notice that in some cases the outcome is embodied in the clause by which the figure is realised; for example in middle variants of the doing & happening type (the outcome of John ran is 'John + run'), and in clause with resultative elements (Attribute, Role) such as I'll boil the eggs hard (outcome: 'eggs + be + hard'), Let's appoint Fred timekeeper (outcome: Fred + be + timekeeper').