A prospective is a grammaticalization of the relationship of a present state to a future situation. It indicates that one is in a present state of being about to do something.
(English)
Bill is going to throw himself off the cliff.
The item going to is a statement of Bill’s present state and is true irrespective of whether he is stopped or not.
Dahl, Osten. 1985.Tense and aspect systems. New York: Basil Blackwell.
Comrie, Bernard. 1985b.Tense. Cambridge, England: Cambridge University.