30.5.4 Safety
It is possible to generate safe or unsafe code.
The safety's scope is type, arity, version and
range.
Let's see an example:
| | (define (foo f v indice)
(car (f (vector-ref v indice))))
|
In safe mode, the result of the compilation will be:
| | (define (foo f v indice)
(let ((pair
(if (and (procedure? f)
;; type check
(= (procedure-arity f) 1))
;; arity check
(if (vector? v)
;; type check
(if (and (integer? k)
;; type check
(>= k 0)
;; range check
(< k (vector-length v)))
;; range check
(f (vector-ref v indice))
(error ...))
(error ...))
(error ...))))
(if (pair? pair)
;; type check
(car pair)
(error ...))))
|
It is possible to remove some or all safe checks. For example, here is
the result of the compilation where safe check on types have been removed:
| | (define (foo f v indice)
(let ((pair (if (= (procedure-arity f) 1)
;; arity check
(if (and (>= k 0)
;; range check
(< k (vector-length v)))
;; range check
(f (vector-ref v indice))
(error ...))
(error ...))))
(car pair)))
|
