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random-state-p

random-state-p Function

Syntax:

random-state-p object → generalized-boolean

Arguments and Values:

object—an object.

generalized-boolean—a generalized boolean.

Description:

Returns true if object is of type random-state; otherwise, returns false.

Examples:

(random-state-p \*random-state\*) → true 
(random-state-p (make-random-state)) → true 
(random-state-p ’test-function) → false

See Also:

make-random-state, *random-state*

Notes:

(random-state-p object) ≡ (typep object ’random-state)

Expanded Reference: random-state-p​

Testing random state objects​

random-state-p returns true if its argument is of type random-state.

(random-state-p *random-state*)
=> T
(random-state-p (make-random-state))
=> T
(random-state-p (make-random-state t))
=> T

Non-random-state objects​

All other objects return false.

(random-state-p nil)
=> NIL
(random-state-p 42)
=> NIL
(random-state-p "random")
=> NIL
(random-state-p 'test-function)
=> NIL
(random-state-p t)
=> NIL

Equivalence to typep​

random-state-p is equivalent to (typep object 'random-state).

(eql (random-state-p *random-state*)
     (typep *random-state* 'random-state))
=> T

(eql (random-state-p 42)
     (typep 42 'random-state))
=> T

Practical use: validating a random state argument​

(defun generate-numbers (n &optional (state *random-state*))
  (unless (random-state-p state)
    (error "Expected a random-state, got ~S" state))
  (loop repeat n collect (random 100 state)))

(generate-numbers 3)
;; => impl-dependent
(generate-numbers 3 (make-random-state))
;; => impl-dependent