Assertion: promise's value | /r/HasProperty | needed
Facets:
value: as in call by need
type: OTHER
Source sentences:
text: The computation can start as soon as the future is created (eager evaluation) or only when the value is actually needed (lazy evaluation), and may be suspended part-way through, or executed in one run.
text: A lazy future is a future that deterministically has lazy evaluation semantics: the computation of the future's value starts when the value is first needed, as in call by need.
text: When a value is needed the expression is evaluated in the evaluation frame of the function.
text: A promise is forced when its value is needed.