Evaluation Order and Infinite Lists
- slide 18 : 27
Conditionals and sequential boolean operators
There are functional language constructs - special forms - for which applicative order reduction would not make sense
(if b x y)
Depending on the value of
b
, either
x
or
y
are evaluated
It would often be harmful to evaluate both
x
and
y
before the selection
(define (fak n) (if (= n 0) 1 (* n (fak (- n 1)))))
(and x y)
and
evaluates its parameters from left to right
In case
x
is false, there is no need to evaluate
y
Often, it would be harmful to evaluate
y
(and (not (= y 0)) (even? (quotient x y)))
