(define (boolean?   x) (equal? 'boolean   (arcana/typeof x)))
(define (char?      x) (equal? 'char      (arcana/typeof x)))
(define (null?      x) (equal? 'null      (arcana/typeof x)))
(define (number?    x) (equal? 'number    (arcana/typeof x)))
(define (pair?      x) (equal? 'pair      (arcana/typeof x)))
(define (procedure? x) (equal? 'procedure (arcana/typeof x)))
(define (string?    x) (equal? 'string    (arcana/typeof x)))
(define (symbol?    x) (equal? 'symbol    (arcana/typeof x)))