a random state.
implementation-dependent.
The current random state, which is used, for example,
by the function random
when a random state is not explicitly supplied.
(random-state-p *random-state*) → true (setq snap-shot (make-random-state)) ;; The series from any given point is random, ;; but if you backtrack to that point, you get the same series. (list (loop for i from 1 to 10 collect (random)) (let ((*random-state* snap-shot)) (loop for i from 1 to 10 collect (random))) (loop for i from 1 to 10 collect (random)) (let ((*random-state* snap-shot)) (loop for i from 1 to 10 collect (random)))) → ((19 16 44 19 96 15 76 96 13 61) (19 16 44 19 96 15 76 96 13 61) (16 67 0 43 70 79 58 5 63 50) (16 67 0 43 70 79 58 5 63 50))
The implementation.
random
.
make-random-state, random, random-state
Binding *random-state*
to a different
random state object correctly saves and
restores the old random state object.