Given this code:
(define (foo)
(define num (+ 1 1)) ; result
of a function that is program-local
(define size (file-size "/some/path")) ; result of a
function that touches the disk, but result never used
(define other-size (file-size "/some/other/path")) ; result of function
that touches disk, result is used
(displayln other-size)
(define x 7) ;
binding of constant value, binding is never used
(define (bar) ;
binding of function, function is never used
(displayln "bar"))
#t)
(for ((i 5))
(foo))
Will any of the above items be compiled away? How many times will each
thing be expanded and compiled -- is bar defined and compiled five separate
times, only once, or not at all?
Separate but related question:
Perl has the 'state' declaration, which says "Declare this as a local
variable, but keep it around with its value preserved after you exit the
function." For example:
sub foo { state $x = 0; say $x++; }
# $x is not visible in this scope
foo();
foo();
foo();
Output:
0
1
2
Is there a simple way to achieve the same thing in Racket?
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